US20150302141A1 - Multicellular metabolic models and methods - Google Patents

Multicellular metabolic models and methods Download PDF

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US20150302141A1
US20150302141A1 US14/572,615 US201414572615A US2015302141A1 US 20150302141 A1 US20150302141 A1 US 20150302141A1 US 201414572615 A US201414572615 A US 201414572615A US 2015302141 A1 US2015302141 A1 US 2015302141A1
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reaction
reactions
cell
cells
data structure
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Imandokht Famili
Christophe H. Schilling
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Genomatica Inc
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    • GPHYSICS
    • G16INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS
    • G16BBIOINFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR GENETIC OR PROTEIN-RELATED DATA PROCESSING IN COMPUTATIONAL MOLECULAR BIOLOGY
    • G16B5/00ICT specially adapted for modelling or simulations in systems biology, e.g. gene-regulatory networks, protein interaction networks or metabolic networks
    • G06F19/12
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/48Biological material, e.g. blood, urine; Haemocytometers
    • G01N33/50Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
    • G01N33/5005Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving human or animal cells
    • G01N33/5008Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving human or animal cells for testing or evaluating the effect of chemical or biological compounds, e.g. drugs, cosmetics
    • G06F19/28
    • G06F19/704
    • GPHYSICS
    • G16INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS
    • G16BBIOINFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR GENETIC OR PROTEIN-RELATED DATA PROCESSING IN COMPUTATIONAL MOLECULAR BIOLOGY
    • G16B20/00ICT specially adapted for functional genomics or proteomics, e.g. genotype-phenotype associations
    • G16B20/20Allele or variant detection, e.g. single nucleotide polymorphism [SNP] detection
    • GPHYSICS
    • G16INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS
    • G16BBIOINFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR GENETIC OR PROTEIN-RELATED DATA PROCESSING IN COMPUTATIONAL MOLECULAR BIOLOGY
    • G16B50/00ICT programming tools or database systems specially adapted for bioinformatics
    • GPHYSICS
    • G16INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS
    • G16BBIOINFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR GENETIC OR PROTEIN-RELATED DATA PROCESSING IN COMPUTATIONAL MOLECULAR BIOLOGY
    • G16B50/00ICT programming tools or database systems specially adapted for bioinformatics
    • G16B50/10Ontologies; Annotations
    • GPHYSICS
    • G16INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS
    • G16CCOMPUTATIONAL CHEMISTRY; CHEMOINFORMATICS; COMPUTATIONAL MATERIALS SCIENCE
    • G16C20/00Chemoinformatics, i.e. ICT specially adapted for the handling of physicochemical or structural data of chemical particles, elements, compounds or mixtures
    • G16C20/30Prediction of properties of chemical compounds, compositions or mixtures
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2500/00Screening for compounds of potential therapeutic value
    • G01N2500/10Screening for compounds of potential therapeutic value involving cells
    • GPHYSICS
    • G16INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS
    • G16BBIOINFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR GENETIC OR PROTEIN-RELATED DATA PROCESSING IN COMPUTATIONAL MOLECULAR BIOLOGY
    • G16B20/00ICT specially adapted for functional genomics or proteomics, e.g. genotype-phenotype associations

Definitions

  • This invention relates generally to analysis of the activity of chemical reaction networks and, more specifically, to computational methods for simulating and predicting the activity of multiple interacting reaction networks.
  • Therapeutic agents including drugs and gene-based agents, are being rapidly developed by the pharmaceutical industry with the goal of preventing or treating human disease. Dietary supplements, including herbal products, vitamins and amino acids, are also being developed and marketed by the nutraceutical industry. Because of the complexity of the biochemical reaction networks in and between human cells, even relatively minor perturbations caused by a therapeutic agent or a dietary component in the abundance or activity of a particular target, such as a metabolite, gene or protein, can affect hundreds of biochemical reactions. These perturbations can lead to desirable therapeutic effects, such as cell stasis or cell death in the case of cancer cells or other pathologically hyperproliferative cells. However, these perturbations can also lead to undesirable side effects, such as production of toxic byproducts, if the systemic effects of the perturbations are not taken into account.
  • Cellular metabolism which is an example of a process involving a highly integrated network of biochemical reactions, is fundamental to all normal cellular or physiological processes, including homeostatis, proliferation, differentiation, programmed cell death (apoptosis) and motility. Alterations in cellular metabolism characterize a vast number of human diseases. For example, tissue injury is often characterized by increased catabolism of glucose, fatty acids and amino acids, which, if persistent, can lead to organ dysfunction. Conditions of low oxygen supply (hypoxia) and nutrient supply, such as occur in solid tumors, result in a myriad of adaptive metabolic changes including activation of glycolysis and neovascularization. Metabolic dysfunctions also contribute to neurodegenerative diseases, cardiovascular disease, neuromuscular diseases, obesity and diabetes. Currently, despite the importance of cellular metabolism to normal and pathological processes, a detailed systemic understanding of cellular metabolism in human cells is currently lacking.
  • the invention provides a computer readable medium or media, having: (a) a first data structure relating a plurality of reactants to a plurality of reactions from a first cell, each of said reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (b) a second data structure relating a plurality of reactants to a plurality of reactions from a second cell, each of said reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (c) a third data structure relating a plurality of intra-system reactants to a plurality of intra-system reactions between said first and second cells, each of said intra-system reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichio
  • the first, second and third data structures also can include a plurality of data structures. Additionally provided is a method for predicting a physiological function of a multicellular organism. The method includes: (a) providing a first data structure relating a plurality of reactants to a plurality of reactions from a first cell, each of said reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (b) providing a second data structure relating a plurality of reactants to a plurality of reactions from a second cell, each of said reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (c) providing a third data structure relating a plurality of intra-system reactants to a plurality of intra-system reactions between said first and second cells, each of said intra-system reactions comprising a
  • FIG. 1 shows a schematic representation of a hypothetical metabolic network.
  • FIG. 2 shows mass balance constraints and flux constraints (reversibility constraints) that can be placed on the hypothetical metabolic network shown in FIG. 1 .
  • FIG. 3 shows the stoichiometric matrix (S) for the hypothetical metabolic network shown in FIG. 1 .
  • FIG. 4 shows, in Panel A, an exemplary biochemical reaction network and in Panel B, an exemplary regulatory control structure for the reaction network in panel A.
  • FIGS. 5-1 through 5 - 9 show a metabolic network of central human metabolism.
  • FIG. 6 shows an example of a gene-protein-reaction association for trios-phosphate isomerase.
  • FIGS. 7-1 through 7 - 35 show a metabolic network of adipocyte metabolism.
  • FIG. 8 shows muscle contraction in a myocyte metabolic model.
  • FIGS. 9-1 through 9 - 35 show a metabolic network of myocyte metabolism.
  • FIGS. 10-1 through 10 - 70 show a metabolic network of coupled adipocyte-myocyte metabolism.
  • FIG. 11 shows triacylglycerol degradation in an adipocyte model.
  • FIG. 12 shows the impairment of muscle contraction as a result of lactate accumulation during anaerobic exercise. Time is in arbitrary unit. Concentration and yield of lactate (Y Lac ) production are in mol/mol glucose.
  • FIG. 13 shows glycogen utilization versus (highlighted on the left) glucose utilization (highlighted on the right) in myocyte.
  • the present invention provides in silico models that describe the interconnections between genes in the Homo sapiens genome and their associated reactions and reactants.
  • the invention also provides in silico models that describe interconnections between different biochemical networks within a cell as well as between cells.
  • the interconnections among different biochemical networks between cells can describe interactions between, for example, groups of cells including cells within different locations, tissues, organs or between cells carrying out different functions of a multicellular organism. Therefore, the models can be used to simulate different aspects of the cellular behavior of a cell derived from a multicellular organism, including a human cell, as well as be used to simulate different aspects of cellular behavioral interactions of groups of cells.
  • Such groups of cells include, for example, eukaryotic cells, such as those of the same tissue type or colonies of prokaryotic cells, or different types of eukaryotic cells derived from the same or different tissue types from a multicellular organism.
  • the different aspects of cellular behavior, including cellular behavioral interactions, can be simulated under different normal, pathological and therapeutic conditions, thereby providing valuable information for therapeutic, diagnostic and research applications.
  • One advantage of the models of the invention is that they provide a holistic approach to simulating and predicting the activity of multicellular organisms, cellular interactions and individual cells, including the activity of Homo sapiens cells. Therefore, the models and methods can be used to simulate the activity of multiple interacting cells, including organs, physiological systems and whole body metabolism for practical diagnostic and therapeutic purposes.
  • the invention is exemplified by reference to a metabolic model of a Homo sapien cell.
  • This in silico model of an eukaryotic cell describes the cellular behavior resulting from two or more interacting networks because it can contain metabolic, regulatory and other network interactions, as described below.
  • the models and methods of the invention applicable to the production and use of a cellular model containing two or more interacting networks also are applicable to the production and use of a multi-network model where the two or more networks are separated between compartments such as cells or tissues of a multicellular organism.
  • a Homo sapien or other eukaryotic cell model of the invention exemplifies application of the models and methods of the invention to models that describe the interaction of multiple biochemical networks between and among cells of a tissue, organ, physiological system or whole organism.
  • the Homo sapiens metabolic models of the invention can be used to determine the effects of changes from aerobic to anaerobic conditions, such as occurs in skeletal muscles during exercise or in tumors, or to determine the effect of various dietary changes.
  • the Homo sapiens metabolic models can also be used to determine the consequences of genetic defects, such as deficiencies in metabolic enzymes such as phosphofructokinase, phosphoglycerate kinase, phosphoglycerate mutase, lactate dehydrogenase and adenosine deaminase.
  • the invention provides a model of multicellular interactions that includes the network reconstruction, characteristics and simulation performance of an integrated two cell model of human adipocyte and myocyte cells.
  • This multicellular model also included an intra-system biochemical network for extracellular physiological systems.
  • the model was generated by reconstructing each of the component biochemical networks within the cells and combining them together with the addition of the intra-system biochemical network and achieved accurate predictive performance of the two cell types under different physiological conditions.
  • Such multicellular metabolic models can be employed for the same determinations as described above for the Homo sapiens metabolic models. The determinations can be performed at the cellular, tissue, physiological system or organism level.
  • the multicellular and Homo sapiens metabolic models also can be used to choose appropriate targets for drug design.
  • targets include genes, proteins or reactants, which when modulated positively or negatively in a simulation produce a desired therapeutic result.
  • the models and methods of the invention can also be used to predict the effects of a therapeutic agent or dietary supplement on a cellular function of interest.
  • the models and methods can be used to predict both desirable and undesirable side effects of the therapeutic agent on an interrelated cellular function in the target cell, as well as the desirable and undesirable effects that may occur in other cell types.
  • the models and methods of the invention can make the drug development process more rapid and cost effective than is currently possible.
  • the multicellular and Homo sapiens metabolic models also can be used to predict or validate the assignment of particular biochemical reactions to the enzyme-encoding genes found in the genome, and to identify the presence of reactions or pathways not indicated by current genomic data.
  • the models can be used to guide the research and discovery process, potentially leading to the identification of new enzymes, medicines or metabolites of clinical importance.
  • the models of the invention are based on a data structure relating a plurality of reactants to a plurality of reactions, wherein each of the reactions includes a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating the substrate and the product.
  • the reactions included in the data structure can be those that are common to all or most cells or to a particular type or species of cell, including Homo sapiens cells, such as core metabolic reactions, or reactions specific for one or more given cell type.
  • reaction is intended to mean a conversion that consumes a substrate or forms a product that occurs in or by a cell.
  • the term can include a conversion that occurs due to the activity of one or more enzymes that are genetically encoded by a genome of the cell.
  • the term can also include a conversion that occurs spontaneously in a cell.
  • Homo sapiens reaction the term is intended to mean a conversion that consumes a substrate or forms a product that occurs in or by a Homo sapiens cell.
  • Conversions included in the term include, for example, changes in chemical composition such as those due to nucleophilic or electrophilic addition, nucleophilic or electrophilic substitution, elimination, isomerization, deamination, phosphorylation, methylation, reduction, oxidation or changes in location such as those that occur due to a transport reaction that moves a reactant from one cellular compartment to another.
  • the substrate and product of the reaction can be chemically the same and the substrate and product can be differentiated according to location in a particular cellular compartment.
  • a reaction that transports a chemically unchanged reactant from a first compartment to a second compartment has as its substrate the reactant in the first compartment and as its product the reactant in the second compartment. It will be understood that when used in reference to an in silico model or data structure, a reaction is intended to be a representation of a chemical conversion that consumes a substrate or produces a product.
  • reactant is intended to mean a chemical that is a substrate or a product of a reaction that occurs in or by a cell.
  • the term can include substrates or products of reactions performed by one or more enzymes encoded by a genome, reactions occurring in cells or organisms that are performed by one or more non-genetically encoded macromolecule, protein or enzyme, or reactions that occur spontaneously in a cell.
  • a Homo sapiens reactant the term is intended to mean a chemical that is a substrate or product of a reaction that occurs in or by a Homo sapiens cell. Metabolites are understood to be reactants within the meaning of the term. It will be understood that when used in reference to an in silico model or data structure, a reactant is intended to be a representation of a chemical that is a substrate or a product of a reaction that occurs in or by a cell.
  • the term “substrate” is intended to mean a reactant that can be converted to one or more products by a reaction.
  • the term can include, for example, a reactant that is to be chemically changed due to nucleophilic or electrophilic addition, nucleophilic or electrophilic substitution, elimination, isomerization, deamination, phosphorylation, methylation, reduction, oxidation or that is to change location such as by being transported across a membrane or to a different compartment.
  • the term “product” is intended to mean a reactant that results from a reaction with one or more substrates.
  • the term can include, for example, a reactant that has been chemically changed due to nucleophilic or electrophilic addition, nucleophilic or electrophilic substitution, elimination, isomerization, deamination, phosphorylation, methylation, reduction or oxidation or that has changed location such as by being transported across a membrane or to a different compartment.
  • the term “stoichiometric coefficient” is intended to mean a numerical constant correlating the number of one or more reactants and the number of one or more products in a chemical reaction.
  • the numbers are integers as they denote the number of molecules of each reactant in an elementally balanced chemical equation that describes the corresponding conversion.
  • the numbers can take on non-integer values, for example, when used in a lumped reaction or to reflect empirical data.
  • the term “plurality,” when used in reference to reactions or reactants including Homo sapiens reactions or reactants, is intended to mean at least 2 reactions or reactants.
  • the term can include any number of reactions or reactants in the range from 2 to the number of naturally occurring reactants or reactions for a particular of cell or cells.
  • the term can include, for example, at least 10, 20, 30, 50, 100, 150, 200, 300, 400, 500, 600 or more reactions or reactants.
  • the number of reactions or reactants can be expressed as a portion of the total number of naturally occurring reactions for a particular cell or cells including a Homo sapiens cell or cells, such as at least 20%, 30%, 50%, 60%, 75%, 90%, 95% or 98% of the total number of naturally occurring reactions that occur in a particular Homo sapiens cell.
  • the term “plurality,” when used in reference to data structures, is intended to mean at least 2 data structures.
  • the term can include any number of data structures in the range from 2 to the number of naturally occurring biochemical networks for a particular subsystem, system, intracellular system, cellular compartment, organelle, extra-cellular space, cytosol, mitochondrion, nucleus, endoplasmic reticulum, group of cells, tissue, organ or organism. Therefore, the term can include, for example, at least about 3, 4, 5, 6, 7, 8, 9, 10, 25, 20, 25, 50, 100 or more biochemical networks.
  • the term also can be expressed as a portion of the total number of naturally occurring networks for any of the particular categories above occurring in prokaryotic or eukaryotic cells including Homo sapiens.
  • data structure is intended to mean a physical or logical relationship among data elements, designed to support specific data manipulation functions.
  • the term can include, for example, a list of data elements that can be added combined or otherwise manipulated such as a list of representations for reactions from which reactants can be related in a matrix or network.
  • the term can also include a matrix that correlates data elements from two or more lists of information such as a matrix that correlates reactants to reactions.
  • Information included in the term can represent, for example, a substrate or product of a chemical reaction, a chemical reaction relating one or more substrates to one or more products, a constraint placed on a reaction, or a stoichiometric coefficient.
  • boundary is intended to mean an upper or lower boundary for a reaction.
  • a boundary can specify a minimum or maximum flow of mass, electrons or energy through a reaction.
  • a boundary can further specify directionality of a reaction.
  • a boundary can be a constant value such as zero, infinity, or a numerical value such as an integer.
  • a boundary can be a variable boundary value as set forth below.
  • variable when used in reference to a constraint is intended to mean capable of assuming any of a set of values in response to being acted upon by a constraint function.
  • function when used in the context of a constraint, is intended to be consistent with the meaning of the term as it is understood in the computer and mathematical arts.
  • a function can be binary such that changes correspond to a reaction being off or on.
  • continuous functions can be used such that changes in boundary values correspond to increases or decreases in activity. Such increases or decreases can also be binned or effectively digitized by a function capable of converting sets of values to discreet integer values.
  • a function included in the term can correlate a boundary value with the presence, absence or amount of a biochemical reaction network participant such as a reactant, reaction, enzyme or gene.
  • a function included in the term can correlate a boundary value with an outcome of at least one reaction in a reaction network that includes the reaction that is constrained by the boundary limit.
  • a function included in the term can also correlate a boundary value with an environmental condition such as time, pH, temperature or redox potential.
  • the term “activity,” when used in reference to a reaction, is intended to mean the amount of product produced by the reaction, the amount of substrate consumed by the reaction or the rate at which a product is produced or a substrate is consumed.
  • the amount of product produced by the reaction, the amount of substrate consumed by the reaction or the rate at which a product is produced or a substrate is consumed can also be referred to as the flux for the reaction.
  • the term “activity,” when used in reference to a Homo sapiens cell or a multicellular interaction, is intended to mean the magnitude or rate of a change from an initial state to a final state.
  • the term can include, for example, the amount of a chemical consumed or produced by a cell, the rate at which a chemical is consumed or produced by a cell, the amount or rate of growth of a cell or the amount of or rate at which energy, mass or electrons flow through a particular subset of reactions.
  • the invention provides a computer readable medium, having a data structure relating a plurality of Homo sapiens reactants to a plurality of Homo sapiens reactions, wherein each of the Homo sapiens reactions includes a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating the substrate and the product.
  • a computer readable medium or media having: (a) a first data structure relating a plurality of reactants to a plurality of reactions from a first cell, each of said reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (b) a second data structure relating a plurality of reactants to a plurality of reactions from a second cell, each of said reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (c) a third data structure relating a plurality of intra-system reactants to a plurality of intra-system reactions between said first and second cells, each of said intra-system reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric
  • the plurality of reactions for any of a multicellular, multi-network or single cell model or method of the invention can include reactions selected from core metabolic reactions or peripheral metabolic reactions.
  • core when used in reference to a metabolic pathway, is intended to mean a metabolic pathway selected from glycolysis/gluconeogenesis, the pentose phosphate pathway (PPP), the tricarboxylic acid (TCA) cycle, glycogen storage, electron transfer system (ETS), the malate/aspartate shuttle, the glycerol phosphate shuttle, and plasma and mitochondrial membrane transporters.
  • the term “peripheral,” when used in reference to a metabolic pathway is intended to mean a metabolic pathway that includes one or more reactions that are not a part of a core metabolic pathway.
  • a plurality of reactants can be related to a plurality of reactions in any data structure that represents, for each reactant, the reactions by which it is consumed or produced.
  • the data structure which is referred to herein as a “reaction network data structure,” serves as a representation of a biological reaction network or system.
  • An example of a reaction network that can be represented in a reaction network data structure of the invention is the collection of reactions that constitute the core metabolic reactions of Homo sapiens , or the metabolic reactions of a skeletal muscle cell, as shown in the Examples.
  • reaction networks that can be represented in a reaction network data structure of the invention are the collection of reactions that constitute the core metabolic reactions and the triacylglycerol (TAG) biosynthetic pathways of an adipocyte cell; the core metabolic reactions and the energy and contractile reactions of a myocyte cell, and the intra-system reactions that supply buffering functions of the kidney.
  • TAG triacylglycerol
  • reaction network data structure The choice of reactions to include in a particular reaction network data structure, from among all the possible reactions that can occur in multicellular organisms or among multicellular interactions, including human cells, depends on the cell type or types and the physiological, pathological or therapeutic condition being modeled, and can be determined experimentally or from the literature, as described further below.
  • the reactions to be included in a particular network data structure of a multicellular interaction can be determined experimentally using, for example, gene or protein expression profiles, where the molecular characteristics of the cell can be correlated to the expression levels.
  • the expression or lack of expression of genes or proteins in a cell type can be used in determining whether a reaction is included in the model by association to the expressed gene(s) and or protein(s).
  • experimental technologies to determine which genes and/or proteins are expressed in a specific cell type, and to further use this information to determine which reactions are present in the cell type of interest. In this way a subset of reactions from all of those reactions that can occur in human cells are selected to comprise the set of reactions that represent a specific cell type.
  • cDNA expression profiles have been demonstrated to be useful, for example, for classification of breast cancer cells (Sorlie et al., Proc. Natl. Acad. Sci. U.S.A. 98(19):10869-10874 (2001)).
  • the methods and models of the invention can be applied to any multicellular interaction as well as to any Homo sapiens cell type at any stage of differentiation, including, for example, embryonic stem cells, hematopoietic stem cells, differentiated hematopoietic cells, skeletal muscle cells, cardiac muscle cells, smooth muscle cells, skin cells, nerve cells, kidney cells, pulmonary cells, liver cells, adipocytes and endocrine cells (e.g. beta islet cells of the pancreas, mammary gland cells, adrenal cells, and other specialized hormone secreting cells).
  • the methods and models of the invention can be applied to any interaction between any of these cell types, including two or more of the same cell type or two or more different cell types. Described below in Example IV is an example of the interactions that occur between myocyte cells and adipocyte cells during different physiological conditions.
  • the methods and models of the invention can be applied to normal cells, pathological cells as well as to combinations of interactions between normal cells, interactions between pathological cells or interactions between normal and pathological cells.
  • Normal cells that exhibit a variety of physiological activities of interest, including homeostasis, proliferation, differentiation, apoptosis, contraction and motility, can be modeled.
  • Pathological cells can also be modeled, including cells that reflect genetic or developmental abnormalities, nutritional deficiencies, environmental assaults, infection (such as by bacteria, viral, protozoan or fungal agents), neoplasia, aging, altered immune or endocrine function, tissue damage, or any combination of these factors.
  • the pathological cells can be representative of any type of pathology, such as a human pathology, including, for example, various metabolic disorders of carbohydrate, lipid or protein metabolism, obesity, diabetes, cardiovascular disease, fibrosis, various cancers, kidney failure, immune pathologies, neurodegenerative diseases, and various monogenetic metabolic diseases described in the Online Mendelian Inheritance in Man database (Center for Medical Genetics, Johns Hopkins University (Baltimore, Md.) and National Center for Biotechnology Information, National Library of Medicine (Bethesda, Md.)).
  • a human pathology including, for example, various metabolic disorders of carbohydrate, lipid or protein metabolism, obesity, diabetes, cardiovascular disease, fibrosis, various cancers, kidney failure, immune pathologies, neurodegenerative diseases, and various monogenetic metabolic diseases described in the Online Mendelian Inheritance in Man database (Center for Medical Genetics, Johns Hopkins University (Baltimore, Md.) and National Center for Biotechnology Information, National Library of Medicine (Bethesda, Md
  • the methods and models of the invention can also be applied to cells or organisms undergoing therapeutic perturbations, such as cells treated with drugs that target participants in a reaction network or cause an effect on an interactive reaction network, cells or tissues treated with gene-based therapeutics that increase or decrease expression of an encoded protein, and cells or tissues treated with radiation.
  • drug refers to a compound of any molecular nature with a known or proposed therapeutic function, including, for example, small molecule compounds, peptides and other macromolecules, peptidomimetics and antibodies, any of which can optionally be tagged with cytostatic, targeting or detectable moieties.
  • gene-based therapeutic refers to nucleic acid therapeutics, including, for example, expressible genes with normal or altered protein activity, antisense compounds, ribozymes, DNAzymes, RNA interference compounds (RNAi) and the like.
  • the therapeutics can target any reaction network participant, in any cellular location, including participants in extracellular, cell surface, cytoplasmic, mitochondrial and nuclear locations.
  • Experimental data that are gathered on the response of cells, tissues, or interactions thereof, to therapeutic treatment, such as alterations in gene or protein expression profiles, can be used to tailor a network or a combination of networks for a pathological state of a particular cell type.
  • the methods and models of the invention can be applied to cells, tissues and physiological systems, including Homo sapiens cells, tissues and physiological systems, as they exist in any form, such as in primary cell isolates or in established cell lines, or in the whole body, in intact organs or in tissue explants. Accordingly, the methods and models can take into account intercellular communications and/or inter-organ communications, the effect of adhesion to a substrate or neighboring cells (such as a stem cell interacting with mesenchymal cells or a cancer cell interacting with its tissue microenvironment, or beta-islet cells without normal stroma), and other interactions relevant to multicellular systems.
  • a substrate or neighboring cells such as a stem cell interacting with mesenchymal cells or a cancer cell interacting with its tissue microenvironment, or beta-islet cells without normal stroma
  • the reactants to be used in a reaction network data structure of the invention can be obtained from or stored in a compound database.
  • compound database is intended to mean a computer readable medium or media containing a plurality of molecules that includes substrates and products of biological reactions.
  • the plurality of molecules can include molecules found in multiple organisms, thereby constituting a universal compound database.
  • the plurality of molecules can be limited to those that occur in a particular organism, thereby constituting an organism-specific compound database.
  • Each reactant in a compound database can be identified according to the chemical species and the cellular compartment in which it is present. Thus, for example, a distinction can be made between glucose in the extracellular compartment versus glucose in the cytosol.
  • each of the reactants can be specified as a metabolite of a primary or secondary metabolic pathway.
  • identification of a reactant as a metabolite of a primary or secondary metabolic pathway does not indicate any chemical distinction between the reactants in a reaction, such a designation can assist in visual representations of large networks of reactions.
  • a subdivided region included in the term can be correlated with a subdivided region of a cell.
  • a subdivided region included in the term can be, for example, the intracellular space of a cell; the extracellular space around a cell; the periplasmic space, the interior space of an organelle such as a mitochondrium, endoplasmic reticulum, Golgi apparatus, vacuole or nucleus; or any subcellular space that is separated from another by a membrane or other physical barrier.
  • a mitochondrial compartment is a subdivided region of the intracellular space of a cell, which in turn, is a subdivided region of a cell or tissue.
  • a subdivided region also can include, for example, different regions or systems of a tissue, organ or physiological system of an organism.
  • Subdivided regions can also be made in order to create virtual boundaries in a reaction network that are not correlated with physical barriers. Virtual boundaries can be made for the purpose of segmenting the reactions in a network into different compartments or substructures.
  • the term “substructure” is intended to mean a portion of the information in a data structure that is separated from other information in the data structure such that the portion of information can be separately manipulated or analyzed.
  • the term can include portions subdivided according to a biological function including, for example, information relevant to a particular metabolic pathway such as an internal flux pathway, exchange flux pathway, central metabolic pathway, peripheral metabolic pathway, or secondary metabolic pathway.
  • the term can include portions subdivided according to computational or mathematical principles that allow for a particular type of analysis or manipulation of the data structure.
  • the reactions included in a reaction network data structure can be obtained from a metabolic reaction database that includes the substrates, products, and stoichiometry of a plurality of metabolic reactions of Homo sapiens , other multicellular organisms or single cell organisms that exhibit biochemical or physiological interactions.
  • the reactants in a reaction network data structure can be designated as either substrates or products of a particular reaction, each with a stoichiometric coefficient assigned to it to describe the chemical conversion taking place in the reaction.
  • Each reaction is also described as occurring in either a reversible or irreversible direction.
  • Reversible reactions can either be represented as one reaction that operates in both the forward and reverse direction or be decomposed into two irreversible reactions, one corresponding to the forward reaction and the other corresponding to the backward reaction.
  • Reactions included in a reaction network data structure can include intra-system or exchange reactions.
  • Intra-system reactions are the chemically and electrically balanced interconversions of chemical species and transport processes, which serve to replenish or drain the relative amounts of certain metabolites. These intra-system reactions can be classified as either being transformations or translocations.
  • a transformation is a reaction that contains distinct sets of compounds as substrates and products, while a translocation contains reactants located in different compartments.
  • a reaction that simply transports a metabolite from the extracellular environment to the cytosol, without changing its chemical composition is solely classified as a translocation, while a reaction that takes an extracellular substrate and converts it into a cytosolic product is both a translocation and a transformation.
  • intra-system reactions can include reactions representing one or more biochemical or physiological functions of an independent cell, tissue, organ or physiological system.
  • the buffering function of the kidneys for the hematopoietic system and intra-cellular environments can be represented as intra-system reactions and be included in a multicellular interaction model either as an independent reaction network or merged with one or more reaction networks of the constituent cells.
  • Exchange reactions are those which constitute sources and sinks, allowing the passage of metabolites into and out of a compartment or across a hypothetical system boundary. These reactions are included in a model for simulation purposes and represent the metabolic demands placed on Homo sapiens . While they may be chemically balanced in certain cases, they are typically not balanced and can often have only a single substrate or product. As a matter of convention the exchange reactions are further classified into demand exchange and input/output exchange reactions.
  • the metabolic demands placed on a multicellular or Homo sapiens metabolic reaction network can be readily determined from the dry weight composition of the cell, cells, tissue, organ or organism which is available in the published literature or which can be determined experimentally.
  • the uptake rates and maintenance requirements for Homo sapiens cells can also be obtained from the published literature or determined experimentally.
  • Input/output exchange reactions are used to allow extracellular reactants to enter or exit the reaction network represented by a model of the invention. For each of the extracellular metabolites a corresponding input/output exchange reaction can be created. These reactions are always reversible with the metabolite indicated as a substrate with a stoichiometric coefficient of one and no products produced by the reaction. This particular convention is adopted to allow the reaction to take on a positive flux value (activity level) when the metabolite is being produced or removed from the reaction network and a negative flux value when the metabolite is being consumed or introduced into the reaction network. These reactions will be further constrained during the course of a simulation to specify exactly which metabolites are available to the cell and which can be excreted by the cell.
  • a demand exchange reaction is always specified as an irreversible reaction containing at least one substrate. These reactions are typically formulated to represent the production of an intracellular metabolite by the metabolic network or the aggregate production of many reactants in balanced ratios such as in the representation of a reaction that leads to biomass formation, also referred to as growth.
  • a demand exchange reactions can be introduced for any metabolite in a model of the invention. Most commonly these reactions are introduced for metabolites that are required to be produced by the cell for the purposes of creating a new cell such as amino acids, nucleotides, phospholipids, and other biomass constituents, or metabolites that are to be produced for alternative purposes. Once these metabolites are identified, a demand exchange reaction that is irreversible and specifies the metabolite as a substrate with a stoichiometric coefficient of unity can be created. With these specifications, if the reaction is active it leads to the net production of the metabolite by the system meeting potential production demands.
  • Examples of processes that can be represented as a demand exchange reaction in a reaction network data structure and analyzed by the methods of the invention include, for example, production or secretion of an individual protein; production or secretion of an individual metabolite such as an amino acid, vitamin, nucleoside, antibiotic or surfactant; production of ATP for extraneous energy requiring processes such as locomotion or muscle contraction; or formation of biomass constituents.
  • an aggregate demand exchange reaction is a reaction used to simulate the concurrent growth demands or production requirements associated with cell growth that are placed on a cell, for example, by simulating the formation of multiple biomass constituents simultaneously at a particular cellular or organismic growth rate.
  • FIG. 1 A specific reaction network is provided in FIG. 1 to exemplify the above-described reactions and their interactions.
  • the reactions can be represented in the exemplary data structure shown in FIG. 3 as set forth below.
  • the reaction network, shown in FIG. 1 includes intra-system reactions that occur entirely within the compartment indicated by the shaded oval such as reversible reaction R 2 which acts on reactants B and G and reaction R 3 which converts one equivalent of B to 2 equivalents of F.
  • the reaction network shown in FIG. 1 also contains exchange reactions such as input/output exchange reactions A xt and E xt , and the demand exchange reaction, V growth , which represents growth in response to the one equivalent of D and one equivalent of F.
  • Other intra-system reactions include R 1 which is a translocation and transformation reaction that translocates reactant A into the compartment and transforms it to reactant G and reaction R 6 which is a transport reaction that translocates reactant E out of the compartment.
  • a reaction network can be represented as a set of linear algebraic equations which can be presented as a stoichiometric matrix S, with S being an m ⁇ n matrix where m corresponds to the number of reactants or metabolites and n corresponds to the number of reactions taking place in the network.
  • S is an m ⁇ n matrix
  • m corresponds to the number of reactants or metabolites
  • n corresponds to the number of reactions taking place in the network.
  • FIG. 3 An example of a stoichiometric matrix representing the reaction network of FIG. 1 is shown in FIG. 3 .
  • each column in the matrix corresponds to a particular reaction n
  • each row corresponds to a particular reactant m
  • each S mn element corresponds to the stoichiometric coefficient of the reactant m in the reaction denoted n.
  • the stoichiometric matrix includes intra-system reactions such as R 2 and R 3 which are related to reactants that participate in the respective reactions according to a stoichiometric coefficient having a sign indicative of whether the reactant is a substrate or product of the reaction and a value correlated with the number of equivalents of the reactant consumed or produced by the reaction.
  • Exchange reactions such as ⁇ E xt and ⁇ A xt are similarly correlated with a stoichiometric coefficient.
  • reactant E the same compound can be treated separately as an internal reactant (E) and an external reactant (E external ) such that an exchange reaction (R 6 ) exporting the compound is correlated by stoichiometric coefficients of ⁇ 1 and 1, respectively.
  • a reaction such as R 5 , which produces the internal reactant (E) but does not act on the external reactant (E external ) is correlated by stoichiometric coefficients of 1 and 0, respectively.
  • Demand reactions such as V growth can also be included in the stoichiometric matrix being correlated with substrates by an appropriate stoichiometric coefficient.
  • a stoichiometric matrix provides a convenient format for representing and analyzing a reaction network because it can be readily manipulated and used to compute network properties, for example, by using linear programming or general convex analysis.
  • a reaction network data structure can take on a variety of formats so long as it is capable of relating reactants and reactions in the manner exemplified above for a stoichiometric matrix and in a manner that can be manipulated to determine an activity of one or more reactions using methods such as those exemplified below.
  • Other examples of reaction network data structures that are useful in the invention include a connected graph, list of chemical reactions or a table of reaction equations.
  • a reaction network data structure can be constructed to include all reactions that are involved in metabolism occurring during the interaction of two or more cells, Homo sapiens cell metabolism or any portion thereof.
  • a portion of an organisms metabolic reactions that can be included in a reaction network data structure of the invention includes, for example, a central metabolic pathway such as glycolysis, the TCA cycle, the PPP or ETS; or a peripheral metabolic pathway such as amino acid biosynthesis, amino acid degradation, purine biosynthesis, pyrimidine biosynthesis, lipid biosynthesis, fatty acid metabolism, vitamin or cofactor biosynthesis, transport processes and alternative carbon source catabolism. Examples of individual pathways within the peripheral pathways are set forth in Table 1.
  • reaction network data structure of the invention examples include, for example, TAG biosynthesis, muscle contraction requirements, bicarbonate buffer system and/or ammonia buffer system. Specific examples of these and other reactions are described further below and in the Examples.
  • a reaction network data structure can include a plurality of Homo sapiens reactions including any or all of the reactions listed in Table 1.
  • a reaction network data structure also can include the reactions set forth in Examples I-IV and include, for example, single reaction networks, multiple reaction networks that interact within a cell as well as multiple reaction networks that interact between cells or physiological systems.
  • reaction network data structure that includes a minimal number of reactions to achieve a particular Homo sapiens activity or activity of a multicellular interaction under a particular set of environmental conditions.
  • a reaction network data structure having a minimal number of reactions can be identified by performing the simulation methods described below in an iterative fashion where different reactions or sets of reactions are systematically removed and the effects observed.
  • the invention provides a computer readable medium, containing a data structure relating a plurality of Homo sapiens reactants to a plurality of Homo sapiens reactions, wherein the plurality of Homo sapiens reactions contains at least 65 reactions.
  • the core metabolic reaction database shown in Tables 2 and 3 contains 65 reactions, and is sufficient to simulate aerobic and anaerobic metabolism on a number of carbon sources, including glucose.
  • the invention provides a computer readable medium containing a data structure relating a plurality of reactants of multicellular interactions to a plurality of reactions from multicellular interactions, wherein the reactions contain at least 430 for a two cell interaction. Such reactions between multicellular interactions are exemplified in Table 11, for example.
  • a reaction network data structure can contain smaller numbers of reactions such as at least 200, 150, 100 or 50 reactions.
  • a reaction network data structure having relatively few reactions can provide the advantage of reducing computation time and resources required to perform a simulation.
  • a reaction network data structure having a particular subset of reactions can be made or used in which reactions that are not relevant to the particular simulation are omitted.
  • larger numbers of reactions can be included in order to increase the accuracy or molecular detail of the methods of the invention or to suit a particular application.
  • a reaction network data structure can contain at least 300, 350, 400, 450, 500, 550, 600 or more reactions up to the number of reactions that occur in or by multicellular interactions, including Homo sapiens , or that are desired to simulate the activity of the full set of reactions occurring in multicellular interactions, including Homo sapiens .
  • a reaction network data structure that is substantially complete with respect to the metabolic reactions of a multicellular organism, including Homo sapiens provides an advantage of being relevant to a wide range of conditions to be simulated, whereas those with smaller numbers of metabolic reactions are specific to a particular subset of conditions to be simulated.
  • a Homo sapiens reaction network data structure can include one or more reactions that occur in or by Homo sapiens and that do not occur, either naturally or following manipulation, in or by another organism, such as Saccharomyces cerevisiae . It is understood that a Homo sapiens reaction network data structure of a particular cell type can also include one or more reactions that occur in another cell type. Addition of such heterologous reactions to a reaction network data structure of the invention can be used in methods to predict the consequences of heterologous gene transfer and protein expression, for example, when designing in vivo and ex vivo gene therapy approaches. Similarly, reaction networks for a multicellular interactions also can include one or more reactions that occur entirely within the species of origin of the cellular interactions or can contain one or more heterologous reactions from one or more different species.
  • reaction network data structure of the invention can be metabolic reactions.
  • a reaction network data structure can also be constructed to include other types of reactions such as regulatory reactions, signal transduction reactions, cell cycle reactions, reactions controlling developmental processes, reactions involved in apoptosis, reactions involved in responses to hypoxia, reactions involved in responses to cell-cell or cell-substrate interactions, reactions involved in protein synthesis and regulation thereof, reactions involved in gene transcription and translation, and regulation thereof, and reactions involved in assembly of a cell and its subcellular components.
  • a reaction network data structure or index of reactions used in the data structure such as that available in a metabolic reaction database, as described above, can be annotated to include information about a particular reaction.
  • a reaction can be annotated to indicate, for example, assignment of the reaction to a protein, macromolecule or enzyme that performs the reaction, assignment of a gene(s) that codes for the protein, macromolecule or enzyme, the Enzyme Commission (EC) number of the particular metabolic reaction, a subset of reactions to which the reaction belongs, citations to references from which information was obtained, or a level of confidence with which a reaction is believed to occur in Homo sapiens or other organism.
  • a computer readable medium or media of the invention can include a gene database containing annotated reactions. Such information can be obtained during the course of building a metabolic reaction database or model of the invention as described below.
  • gene database is intended to mean a computer readable medium or media that contains at least one reaction that is annotated to assign a reaction to one or more macromolecules that perform the reaction or to assign one or more nucleic acid that encodes the one or more macromolecules that perform the reaction.
  • a gene database can contain a plurality of reactions, some or all of which are annotated.
  • An annotation can include, for example, a name for a macromolecule; assignment of a function to a macromolecule; assignment of an organism that contains the macromolecule or produces the macromolecule; assignment of a subcellular location for the macromolecule; assignment of conditions under which a macromolecule is regulated with respect to performing a reaction, being expressed or being degraded; assignment of a cellular component that regulates a macromolecule; an amino acid or nucleotide sequence for the macromolecule; a mRNA isoform, enzyme isoform, or any other desirable annotation or annotation found for a macromolecule in a genome database such as those that can be found in Genbank, a site maintained by the NCBI (ncbi.nlm.gov), the Kyoto Encyclopedia of Genes and Genomes (KEGG) (www.genome.ad.jp/kegg/), the protein database SWISS-PROT (ca.expasy.org/sprot/), the LocusLink database maintained by the NCBI (www.ncbi.nlm.nih.
  • a gene database of the invention can include a substantially complete collection of genes or open reading frames in a multicellular organism, including Homo sapiens , or a substantially complete collection of the macromolecules encoded by the organism's genome.
  • a gene database can include a portion of genes or open reading frames in an organism or a portion of the macromolecules encoded by the organism's genome, such as the portion that includes substantially all metabolic genes or macromolecules. The portion can be at least 10%, 15%, 20%, 25%, 50%, 75%, 90% or 95% of the genes or open reading frames encoded by the organism's genome, or the macromolecules encoded therein.
  • a gene database can also include macromolecules encoded by at least a portion of the nucleotide sequence for the organism's genome such as at least 10%, 15%, 20%, 25%, 50%, 75%, 90% or 95% of the organism's genome.
  • a computer readable medium or media of the invention can include at least one reaction for each macromolecule encoded by a portion of an organism's genome, including a Homo sapiens genome.
  • An in silico model of multicellular interactions including a Homo sapiens model, of the invention can be built by an iterative process which includes gathering information regarding particular reactions to be added to a model, representing the reactions in a reaction network data structure, and performing preliminary simulations wherein a set of constraints is placed on the reaction network and the output evaluated to identify errors in the network. Errors in the network such as gaps that lead to non-natural accumulation or consumption of a particular metabolite can be identified as described below and simulations repeated until a desired performance of the model is attained.
  • An exemplary method for iterative model construction is provided in Example I.
  • an iterative process includes producing one or more component reaction networks followed by combining the components into a higher order multi-network system, as described in Example IV.
  • components can include the central metabolism reaction network and the cell specific reaction networks such as TAG biosynthesis for adipocytes or muscle contraction for myocytes. Combination of the central metabolism and the cell specific reaction networks into a single model produces, for example, a cell specific reaction network.
  • Components also can include the individual cell types, tissues, physiological systems or intra-system reaction networks that are constituents of the larger multicellular system. Combining these components into a larger model produces, for example, a model describing the relationships and interactions of the multicellular system together with its various interactions.
  • the invention provides a method for making a data structure relating a plurality of reactants to a plurality of reactions in a computer readable medium or media.
  • the method includes the steps of: (a) identifying a plurality of reactions and a plurality of reactants that are substrates and products of the reactions; (b) relating the plurality of reactants to the plurality of Homo sapiens reactions in a data structure, wherein each of the reactions includes a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating the substrate and the product; (c) making a constraint set for the plurality of reactions; (d) providing an objective function; (e) determining at least one flux distribution that minimizes or maximizes the objective function when the constraint set is applied to the data structure, and (f) if the at least one flux distribution is not predictive of physiology, then adding a reaction to or deleting a reaction from the data structure and repeating step (e),
  • Information to be included in a data structure of the invention can be gathered from a variety of sources including, for example, annotated genome sequence information and biochemical literature.
  • Sources of annotated human genome sequence information include, for example, KEGG, SWISS-PROT, LocusLink, the Enzyme Nomenclature database, the International Human Genome Sequencing Consortium and commercial databases.
  • KEGG contains a broad range of information, including a substantial amount of metabolic reconstruction.
  • the genomes of 304 organisms can be accessed here, with gene products grouped by coordinated functions, often represented by a map (e.g., the enzymes involved in glycolysis would be grouped together).
  • the maps are biochemical pathway templates which show enzymes connecting metabolites for various parts of metabolism. These general pathway templates are customized for a given organism by highlighting enzymes on a given template which have been identified in the genome of the organism. Enzymes and metabolites are active and yield useful information about stoichiometry, structure, alternative names and the like, when accessed.
  • SWISS-PROT contains detailed information about protein function. Accessible information includes alternate gene and gene product names, function, structure and sequence information, relevant literature references, and the like.
  • LocusLink contains general information about the locus where the gene is located and, of relevance, tissue specificity, cellular location, and implication of the gene product in various disease states.
  • the Enzyme Nomenclature database can be used to compare the gene products of two organisms. Often the gene names for genes with similar functions in two or more organisms are unrelated. When this is the case, the E.C. (Enzyme Commission) numbers can be used as unambiguous indicators of gene product function.
  • E.C. Enzyme Commission
  • the information in the Enzyme Nomenclature database is also published in Enzyme Nomenclature (Academic Press, San Diego, Calif., 1992) with 5 supplements to date, all found in the European Journal of Biochemistry (Blackwell Science, Malden, Mass.).
  • Sources of biochemical information include, for example, general resources relating to metabolism, resources relating specifically to human metabolism, and resources relating to the biochemistry, physiology and pathology of specific human cell types.
  • biochemical information which is information related to the experimental characterization of a chemical reaction, often directly indicating a protein(s) associated with a reaction and the stoichiometry of the reaction or indirectly demonstrating the existence of a reaction occurring within a cellular extract
  • genetic information which is information related to the experimental identification and genetic characterization of a gene(s) shown to code for a particular protein(s) implicated in carrying out a biochemical event
  • genomic information which is information related to the identification of an open reading frame and functional assignment, through computational sequence analysis, that is then linked to a protein performing a biochemical event
  • physiological information which is information related to overall cellular physiology, fitness characteristics, substrate utilization, and phenotyping results, which provide evidence of the assimilation or dissimilation of a compound used to infer the presence of specific biochemical event (in particular translocations);
  • modeling information which is information generated through the course
  • reaction network data structure can contain reactions that add or delete steps to or from a particular reaction pathway. For example, reactions can be added to optimize or improve performance of a model for multicellular interactions in view of empirically observed activity. Alternatively, reactions can be deleted to remove intermediate steps in a pathway when the intermediate steps are not necessary to model flux through the pathway. For example, if a pathway contains 3 nonbranched steps, the reactions can be combined or added together to give a net reaction, thereby reducing memory required to store the reaction network data structure and the computational resources required for manipulation of the data structure.
  • the reactions that occur due to the activity of gene-encoded enzymes can be obtained from a genome database which lists genes identified from genome sequencing and subsequent genome annotation. Genome annotation consists of the locations of open reading frames and assignment of function from homology to other known genes or empirically determined activity. Such a genome database can be acquired through public or private databases containing annotated nucleic acid or protein sequences, including Homo sapiens sequences. If desired, a model developer can perform a network reconstruction and establish the model content associations between the genes, proteins, and reactions as described, for example, in Covert et al. Trends in Biochemical Sciences 26:179-186 (2001) and Palsson, WO 00/46405.
  • Annotating a metabolic reaction database with these associations can allow the methods to be used to determine the effects of adding or eliminating a particular reaction not only at the reaction level, but at the genetic or protein level in the context of running a simulation or predicting a multicellular interaction activity, including Homo sapiens activity.
  • a reaction network data structure of the invention can be used to determine the activity of one or more reactions in a plurality of reactions occurring from multicellular interactions, including a plurality of Homo sapiens reactions, independent of any knowledge or annotation of the identity of the protein that performs the reaction or the gene encoding the protein.
  • a model that is annotated with gene or protein identities can include reactions for which a protein or encoding gene is not assigned. While a large portion of the reactions in a cellular metabolic network are associated with genes in the organism's genome, there are also a substantial number of reactions included in a model for which there are no known genetic associations.
  • Such reactions can be added to a reaction database based upon other information that is not necessarily related to genetics such as biochemical or cell based measurements or theoretical considerations based on observed biochemical or cellular activity. For example, there are many reactions that can either occur spontaneously or are not protein-enabled reactions. Furthermore, the occurrence of a particular reaction in a cell for which no associated proteins or genetics have been currently identified can be indicated during the course of model building by the iterative model building methods of the invention.
  • the reactions in a reaction network data structure or reaction database can be assigned to subsystems by annotation, if desired.
  • the reactions can be subdivided according to biological criteria, such as according to traditionally identified metabolic pathways (glycolysis, amino acid metabolism and the like) or according to mathematical or computational criteria that facilitate manipulation of a model that incorporates or manipulates the reactions. Methods and criteria for subdividing a reaction database are described in further detail in Schilling et al., J. Theor. Biol. 203:249-283 (2000), and in Schuster et al., Bioinformatics 18:351-361 (2002).
  • the use of subsystems can be advantageous for a number of analysis methods, such as extreme pathway analysis, and can make the management of model content easier.
  • a reaction network data structure can include any number of desired subsystems including, for example, 2 or more subsystems, 5 or more subsystems, 10 or more subsystems, 25 or more subsystems or 50 or more subsystems.
  • the reactions in a reaction network data structure or metabolic reaction database can be annotated with a value indicating the confidence with which the reaction is believed to occur in one or more cells of a multicellular interaction or in one or more reaction networks within a cell such as a Homo sapiens cell.
  • the level of confidence can be, for example, a function of the amount and form of supporting data that is available. This data can come in various forms including published literature, documented experimental results, or results of computational analyses. Furthermore, the data can provide direct or indirect evidence for the existence of a chemical reaction in a cell based on genetic, biochemical, and/or physiological data.
  • the invention further provides a computer readable medium, containing (a) a data structure relating a plurality of Homo sapiens reactants to a plurality of Homo sapiens reactions, wherein each of the Homo sapiens reactions includes a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating the substrate and the product, and (b) a constraint set for the plurality of Homo sapiens reactions.
  • the computer readable medium or media can relate a plurality of reactions to a plurality of reactions within first and second cells and for an intra-system between first and second interacting cells.
  • Constraints can be placed on the value of any of the fluxes in the metabolic network using a constraint set. These constraints can be representative of a minimum or maximum allowable flux through a given reaction, possibly resulting from a limited amount of an enzyme present. Additionally, the constraints can determine the direction or reversibility of any of the reactions or transport fluxes in the reaction network data structure. Based on the in vivo environment where multiple cells interact, such as in a human organism, the metabolic resources available to the cell for biosynthesis of essential molecules for can be determined. Allowing the corresponding transport fluxes to be active provides the in silico interaction between cells with inputs and outputs for substrates and by-products produced by the metabolic network.
  • constraints can be placed on each reaction in the exemplary format shown in FIG. 2 , as follows.
  • the constraints are provided in a format that can be used to constrain the reactions of the stoichiometric matrix shown in FIG. 3 .
  • the format for the constraints used for a matrix or in linear programming can be conveniently represented as a linear inequality such as
  • v j is the metabolic flux vector
  • b j is the minimum flux value
  • a j is the maximum flux value.
  • a j can take on a finite value representing a maximum allowable flux through a given reaction or b j can take on a finite value representing minimum allowable flux through a given reaction.
  • the flux may remain unconstrained by setting b j to negative infinity and a j to positive infinity as shown for reaction R 2 in FIG. 2 .
  • the ability of a reaction to be actively occurring is dependent on a large number of additional factors beyond just the availability of substrates.
  • factors which can be represented as variable constraints in the models and methods of the invention include, for example, the presence of cofactors necessary to stabilize the protein/enzyme, the presence or absence of enzymatic inhibition and activation factors, the active formation of the protein/enzyme through translation of the corresponding mRNA transcript, the transcription of the associated gene(s) or the presence of chemical signals and/or proteins that assist in controlling these processes that ultimately determine whether a chemical reaction is capable of being carried out within an organism.
  • factors which can be represented as variable constraints in the models and methods of the invention include, for example, the presence of cofactors necessary to stabilize the protein/enzyme, the presence or absence of enzymatic inhibition and activation factors, the active formation of the protein/enzyme through translation of the corresponding mRNA transcript, the transcription of the associated gene(s) or the presence of chemical signals and/or proteins that assist in controlling these processes that ultimately determine whether a chemical reaction
  • a cell secretes signaling molecules that may be carried far afield to act on distant targets (endocrine signaling), or act as local mediators (paracrine signaling).
  • endocrine signaling molecules include hormones such as insulin
  • paracrine signaling molecules include neurotransmitters such as acetylcholine.
  • the invention provides a computer readable medium or media, including (a) a data structure relating a plurality of Homo sapiens reactants to a plurality of Homo sapiens reactions, wherein each of the reactions includes a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating the substrate and the product, and wherein at least one of the reactions is a regulated reaction; and (b) a constraint set for the plurality of reactions, wherein the constraint set includes a variable constraint for the regulated reaction.
  • the invention provides a computer readable medium or media including data structures for two or more cells and for an intra-system and a constraint set for the plurality of reactions within the data structures that includes a variable constraint for a regulated reaction.
  • regulated when used in reference to a reaction in a data structure, is intended to mean a reaction that experiences an altered flux due to a change in the value of a constraint or a reaction that has a variable constraint.
  • regulatory reaction is intended to mean a chemical conversion or interaction that alters the activity of a protein, macromolecule or enzyme.
  • a chemical conversion or interaction can directly alter the activity of a protein, macromolecule or enzyme such as occurs when the protein, macromolecule or enzyme is post-translationally modified or can indirectly alter the activity of a protein, macromolecule or enzyme such as occurs when a chemical conversion or binding event leads to altered expression of the protein, macromolecule or enzyme.
  • transcriptional or translational regulatory pathways can indirectly alter a protein, macromolecule or enzyme or an associated reaction.
  • indirect regulatory reactions can include reactions that occur due to downstream components or participants in a regulatory reaction network.
  • the term is intended to mean a first reaction that is related to a second reaction by a function that alters the flux through the second reaction by changing the value of a constraint on the second reaction.
  • regulatory data structure is intended to mean a representation of an event, reaction or network of reactions that activate or inhibit a reaction, the representation being in a format that can be manipulated or analyzed.
  • An event that activates a reaction can be an event that initiates the reaction or an event that increases the rate or level of activity for the reaction.
  • An event that inhibits a reaction can be an event that stops the reaction or an event that decreases the rate or level of activity for the reaction.
  • Reactions that can be represented in a regulatory data structure include, for example, reactions that control expression of a macromolecule that in turn, performs a reaction such as transcription and translation reactions, reactions that lead to post translational modification of a protein or enzyme such as phosphorylation, dephosphorylation, prenylation, methylation, oxidation or covalent modification, reactions that process a protein or enzyme such as removal of a pre- or pro-sequence, reactions that degrade a protein or enzyme or reactions that lead to assembly of a protein or enzyme.
  • a reaction such as transcription and translation reactions
  • reactions that lead to post translational modification of a protein or enzyme such as phosphorylation, dephosphorylation, prenylation, methylation, oxidation or covalent modification
  • reactions that process a protein or enzyme such as removal of a pre- or pro-sequence
  • reactions that degrade a protein or enzyme or reactions that lead to assembly of a protein or enzyme include, for example, reactions that control expression of a macromolecule that in turn, perform
  • regulatory event is intended to mean a modifier of the flux through a reaction that is independent of the amount of reactants available to the reaction.
  • a modification included in the term can be a change in the presence, absence, or amount of an enzyme that performs a reaction.
  • a modifier included in the term can be a regulatory reaction such as a signal transduction reaction or an environmental condition such as a change in pH, temperature, redox potential or time.
  • a regulatory event is intended to be a representation of a modifier of the flux through a Homo sapiens reaction or reaction occurring in one or more cells in a multicellular interaction that is independent of the amount of reactants available to the reaction.
  • the effects of regulation on one or more reactions that occur in Homo sapiens can be predicted using an in silico Homo sapiens model or multicellular model of the invention. Regulation can be taken into consideration in the context of a particular condition being examined by providing a variable constraint for the reaction in an in silico Homo sapiens model or multicellular model. Such constraints constitute condition-dependent constraints.
  • a data structure can represent regulatory reactions as Boolean logic statements (Reg-reaction). The variable takes on a value of 1 when the reaction is available for use in the reaction network and will take on a value of 0 if the reaction is restrained due to some regulatory feature.
  • a series of Boolean statements can then be introduced to mathematically represent the regulatory network as described for example in Covert et al. J. Theor.
  • a Boolean rule can state that:
  • reaction R2 can occur if reaction A_in is not occurring (i.e. if metabolite A is not present). Similarly, it is possible to assign the regulation to a variable A which would indicate an amount of A above or below a threshold that leads to the inhibition of reaction R2.
  • Any function that provides values for variables corresponding to each of the reactions in the biochemical reaction network can be used to represent a regulatory reaction or set of regulatory reactions in a regulatory data structure. Such functions can include, for example, fuzzy logic, heuristic rule-based descriptions, differential equations or kinetic equations detailing system dynamics.
  • reaction constraint placed on a reaction can be incorporated into an in silico Homo sapiens model or multicellular model of interacting cells using the following general equation:
  • the behavior of the Homo sapiens reaction network or one or more reaction networks of a multicellular interaction can be simulated for the conditions considered as set forth below.
  • the regulatory structure includes a general control stating that a reaction is inhibited by a particular environmental condition. Using a general control of this type, it is possible to incorporate molecular mechanisms and additional detail into the regulatory structure that is responsible for determining the active nature of a particular chemical reaction within an organism.
  • Regulation can also be simulated by a model of the invention and used to predict a Homo sapiens physiological function without knowledge of the precise molecular mechanisms involved in the reaction network being modeled.
  • the model can be used to predict, in silico, overall regulatory events or causal relationships that are not apparent from in vivo observation of any one reaction in a network or whose in vivo effects on a particular reaction are not known.
  • Such overall regulatory effects can include those that result from overall environmental conditions such as changes in pH, temperature, redox potential, or the passage of time.
  • the models and method of the invention are applicable to a wide range of multicellular interactions.
  • the multicellular interactions include, for example, interactions between prokaryotic cells such as colony growth and chemotaxis.
  • the multicellular interactions include, for example, interactions between two or more eukaryotic cells such as the concerted action of two or more cells of the same or different cell type.
  • a specific example of the concerted action of the same cell type includes the combined output of the contractile activity of myocytes.
  • a specific example of the concerted action of different cell types includes the energy production of adipocyte cells and the contractile activity of myocyte cells based on the consumption of energy available from the adipocyte cells.
  • Multicellular interactions also can include, for example, interactions between host cells and a pathogen, such as a bacteria, virus or worm, as well as symbiotic interactions between host cells and microbes, for example.
  • a symbiotic microbe can include, for example, E. coli .
  • Further examples of host and microbe interactions include bacterial communities that reside in the skin and mouth and the vagina flora, providing the host with a defense against infections.
  • the models and methods of the invention also can be used to reconstruction the reaction networks between a plurality of dynamic multicellular interactions including, for example, interactions between host cells or tissues, pathogen and symbiotic microbe.
  • Multicellular interactions also include, for example, interactions between cells of different tissues, different organs and/or physiological systems as well as interactions between some or all cells, tissues organs and/or physiological systems within a multicellular organism.
  • Specific examples of such interactions include organismic homeostasis, signal transduction, the endocrine system, the exocrine system, sensory transduction, secretion, the hematopoietic system, the immune system, cell migration, cell adherence, cell invasion and neuronal and synaptic transduction.
  • Numerous other multicellular interactions are well known in the art and can similarly be reconstructed and simulated to predict an activity thereof using the models and methods of the invention.
  • multicellular interactions include, for example, all interactions occurring between two or more cells such as those cells set forth in Table 5 below. Such multicellular interactions can occur between cells within the same or different physiological category or functional characterization. Similarly, such multicellular interactions also can occur between cells within the same and between different physiological categories or functional characterizations. The number and types of different cellular interactions will be determined by the multicellular model being produced using the methods of the invention.
  • Models of multicellular interactions also can include, for example, interactions between cells of one or more tissues and organs.
  • the models and methods of the invention are applicable to predict the activity of interactions between some or all cell types of a tissue or organ.
  • the models and methods of the invention also can include reaction networks that include interactions between some or all cell types of two or more tissues or organs. Specific examples of tissues or organs and their respective cell types and functions are shown below in Table 6.
  • the models and methods of the invention can include, for example, some or all of these interactions to predict their respective activities.
  • Table 7 exemplifies the cell types of a liver.
  • the models and methods of the invention can be used to construct an in silico reconstruction of the reaction networks for some or all of these cell types to predict some or all of the activities of the liver.
  • an in silico reconstruction of reaction networks for some or all multicellular interactions exemplified in Tables 5-7, including those within and between tissues and organs, can be produced that can be used to predict some or all activities of one or more tissues or of an organism. Therefore, the invention provides for the in silico reconstruction of whole organisms, including human organisms, tissues, cells and physical or physiological functions performed by such cellular systems.
  • the invention also provides for the in silico reconstruction of a plurality of reaction networks that interact to perform the same or different activity.
  • the plurality can be a small, medium or large plurality and can reside within the same cell, different cells or in different tissues or organisms. Specific examples of such pluralities residing within the same cell include the reaction networks exemplified below in Example IV for a myocyte or for an adipocyte. Specific examples of such pluralities residing in different cells or tissues include the reaction networks exemplified below in Example IV for coupled adipocyte-myocyte metabolism. Another example of interactions between different reaction networks within different networks includes interactions between pathogen and host cells.
  • a computer readable medium or media can be produced that includes a plurality of data structures each relating a plurality of reactants to a plurality of reactions from each cell within the multicellular interaction.
  • the reactions include a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating the substrate and said product
  • the plurality of data structures can include a first data structure and a second data structure corresponding to the reactions within the two cells or populations of two cell types.
  • the data structures will describe the reaction networks for each cell.
  • a third data structure is particularly useful for relating a plurality of intra-system reactants to a plurality of intra-system reactions between the first and second cells.
  • Each of the intra-system reactions includes a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating the substrate and said product.
  • the intra-system data structure can be included in the reconstruction as an independent data structure or as a component of one or more data structures for either or both cells within such a two cell interaction model.
  • FIGS. 10-1 through 10 - 70 A specific example of intra-system reactions represented by a third data structure is shown in FIGS. 10-1 through 10 - 70 for the bicarbonate and ammonia buffer systems employed in the two cell model describing adipocyte and myocyte interactions.
  • a computer readable medium or media describing a multicellular interaction also will contain a constraint set for the plurality of reactions for each of the first, second and third data structures as well as commands for determining at least one flux distribution that minimizes or maximizes an objective function when said constraint set is applied to said first and second data structures.
  • the objective function can be, for example, those objective functions exemplified previously, those exemplified below or in the Examples as well as various other object functions well known to those skilled in the art given the teachings and guidance provided herein. Solving the optimization problem by determining one or more flux distribution will predict a physiological function of occurring as a result of the interaction between the first and second cells of the model.
  • Each of the first, second or third data structures can include one or more reaction networks.
  • a reaction network for each of the cells exemplified therein can be defined as the different networks within each cell such as central metabolism and the cell specific reactions.
  • the adipocyte and myocyte cells each contain at least two reaction networks. When combined together with the intra-cellular reaction network and the exchange reactions, the interactions of the two cells exemplified in FIG. 6 can be described by at least five different reaction networks.
  • each of the first, second or third data structures can consist of a plurality of two or more reaction networks including, for example, 2, 3, 4, 5, 10, 20 or 25 or more as well as all integer numbers between and above these exemplary numbers.
  • the models and methods of the invention can be generated and used to predict an activity and/or physiological function of the intercellular network interactions or the intracellular network interaction.
  • the latter interactions for example, also predict an activity and/or a physiological function of the interactions between two or more cells including cells of different tissues, organs of a multicellular organism or of a whole organism.
  • the models and methods of the invention also can employ greater than three data structures as exemplified above.
  • the models and method of the invention can comprise one or more fourth data structures having one or more fourth constraint sets where each fourth data structure relates a plurality of reactants to a plurality of reactions from a cell already included in the model or from one or more third cells within the multicellular interaction.
  • Use of one or more fourth data structures is particularly useful when reconstructing a interactions between three or more interacting cells including a large plurality of cells such as the cells within a tissue, organ, physiological system or organism.
  • Each of the reactions within such fourth data structures include a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating the substrate and said product.
  • the number of fourth data structures can correspond to the number of cells greater than the first and second cells of the multicellular interaction and include, for example, a plurality of data structures.
  • the plurality of data structures for three or more interacting cells can correspond to different cells within the cellular interaction as well as correspond to different cell types within the cellular interaction.
  • the number of cells can include, for example, at least 4 cells, 5 cells, 6 cells, 7 cells, 8 cells, 9 cells, 10 cells, 100 cells, 1000 cells, 5000 cells, 10,000 cells or more.
  • the number of cells within a multicellular interaction model or used in a method of predicting a behavior of such multicellular interactions can include some or all cells which constitute a group of interacting cells, a tissue, organ, physiological system or whole organism.
  • the multicellular interaction models and methods of the invention also can include some or all cells which constitute a group of interacting cells of different types or from different tissues, organs, physiological systems or organisms.
  • the organism can be single cell prokaryotic or eukaryotic organism or multicellular eukaryotic organisms.
  • cell types include a mammary gland cell, hepatocyte, white fat cell, brown fat cell, liver lipocyte, red skeletal muscle cell, white skeletal muscle cell, intermediate skeletal muscle cell, smooth muscle cell, red blood cell, adipocyte, monocyte, reticulocyte, fibroblast, neuronal cell epithelial cell or one or more cells set forth in Table 5.
  • physiological functions resulting from multicellular interactions include metabolite yield, ATP yield, biomass demand, growth, triacylglycerol storage, muscle contraction, milk secretion and oxygen transport capacity.
  • Intra-system reactions of a multicellular interaction model or method of the invention has been exemplified above and below with reference to the extracellular in vivo environment and, in particular, with reference to buffering this environment by supplying functions of the renal system.
  • any extracellular reaction, plurality of reactions, function of the extracellular space or function supplied into the extracellular space by another cell, tissue or physiological system can be employed as an intra-system reaction network.
  • Such reactions or activities can represent normal or pathological conditions or both conditions occurring within this intra-system environment.
  • Specific examples of intra-system reactions include one or more reactions performed in the hematopoietic system, urine, connective tissue, contractile tissue or cells, lymphatic system, respiratory system or renal system.
  • Reactions or reactants included in one or more intra-system data structures can be, for example, bicarbonate buffer system, an ammonia buffer system, a hormone, a signaling molecule, a vitamin, a mineral or a combination thereof.
  • the in silico models of multicellular or multi-network interactions can be implemented on any conventional host computer system, such as those based on Intel® microprocessors and running Microsoft Windows operating systems.
  • Other systems such as those using the UNIX or LINUX operating system and based on IBM®, DEC® or Motorola® microprocessors are also contemplated.
  • the systems and methods described herein can also be implemented to run on client-server systems and wide-area networks, such as the Internet.
  • Software to implement a method or model of the invention can be written in any well-known computer language, such as Java, C, C++, Visual Basic, FORTRAN or COBOL and compiled using any well-known compatible compiler.
  • the software of the invention normally runs from instructions stored in a memory on a host computer system.
  • a memory or computer readable medium can be a hard disk, floppy disc, compact disc, magneto-optical disc, Random Access Memory, Read Only Memory or Flash Memory.
  • the memory or computer readable medium used in the invention can be contained within a single computer or distributed in a network.
  • a network can be any of a number of conventional network systems known in the art such as a local area network (LAN) or a wide area network (WAN).
  • LAN local area network
  • WAN wide area network
  • Client-server environments, database servers and networks that can be used in the invention are well known in the art.
  • the database server can run on an operating system such as UNIX, running a relational database management system, a World Wide Web application and a World Wide Web server.
  • an operating system such as UNIX
  • relational database management system running a relational database management system
  • World Wide Web application running a relational database management system
  • World Wide Web server running a relational database management system
  • Other types of memories and computer readable media are also contemplated to function within the scope of the invention.
  • a database or data structure of the invention can be represented in a markup language format including, for example, Standard Generalized Markup Language (SGML), Hypertext markup language (HTML) or Extensible Markup language (XML).
  • Markup languages can be used to tag the information stored in a database or data structure of the invention, thereby providing convenient annotation and transfer of data between databases and data structures.
  • an XML format can be useful for structuring the data representation of reactions, reactants and their annotations; for exchanging database contents, for example, over a network or internet; for updating individual elements using the document object model; or for providing differential access to multiple users for different information content of a data base or data structure of the invention.
  • XML programming methods and editors for writing XML code are known in the art as described, for example, in Ray, “Learning XML” O'Reilly and Associates, Sebastopol, Calif. (2001).
  • a set of constraints can be applied to a reaction network data structure to simulate the flux of mass through the reaction network under a particular set of environmental conditions specified by a constraints set. Because the time constants characterizing metabolic transients and/or metabolic reactions are typically very rapid, on the order of milli-seconds to seconds, compared to the time constants of cell growth on the order of hours to days, the transient mass balances can be simplified to only consider the steady state behavior. Referring now to an example where the reaction network data structure is a stoichiometric matrix, the steady state mass balances can be applied using the following system of linear equations
  • Equation 1 represents the reaction constraints and mass balances, respectively, effectively define the capabilities and constraints of the metabolic genotype and the organism's metabolic potential. All vectors, v, that satisfy Equation 5 are said to occur in the mathematical nullspace of S.
  • the null space defines steady-state metabolic flux distributions that do not violate the mass, energy, or redox balance constraints.
  • the number of fluxes is greater than the number of mass balance constraints, thus a plurality of flux distributions satisfy the mass balance constraints and occupy the null space.
  • the null space which defines the feasible set of metabolic flux distributions, is further reduced in size by applying the reaction constraints set forth in Equation 1 leading to a defined solution space.
  • a point in this space represents a flux distribution and hence a metabolic phenotype for the network.
  • An optimal solution within the set of all solutions can be determined using mathematical optimization methods when provided with a stated objective and a constraint set. The calculation of any solution constitutes a simulation of the model.
  • Objectives for activity of a human cell can be chosen. While the overall objective of a multi-cellular organism may be growth or reproduction, individual human cell types generally have much more complex objectives, even to the seemingly extreme objective of apoptosis (programmed cell death), which may benefit the organism but certainly not the individual cell. For example, certain cell types may have the objective of maximizing energy production, while others have the objective of maximizing the production of a particular hormone, extracellular matrix component, or a mechanical property such as contractile force. In cases where cell reproduction is slow, such as human skeletal muscle, growth and its effects need not be taken into account. In other cases, biomass composition and growth rate could be incorporated into a “maintenance” type of flux, where rather than optimizing for growth, production of precursors is set at a level consistent with experimental knowledge and a different objective is optimized.
  • biomass generation can be defined as an exchange reaction that removes intermediate metabolites in the appropriate ratios and represented as an objective function.
  • this reaction flux can be formed to utilize energy molecules such as ATP, NADH and NADPH so as to incorporate any maintenance requirement that must be met.
  • This new reaction flux then becomes another constraint/balance equation that the system must satisfy as the objective function.
  • adding such a constraint is analogous to adding the additional column V growth to the stoichiometric matrix to represent fluxes to describe the production demands placed on the metabolic system. Setting this new flux as the objective function and asking the system to maximize the value of this flux for a given set of constraints on all the other fluxes is then a method to simulate the growth of the organism.
  • Z is the objective which is represented as a linear combination of metabolic fluxes v i using the weights c i in this linear combination.
  • the optimization problem can also be stated as the equivalent maximization problem; i.e. by changing the sign on Z.
  • Any commands for solving the optimization problem can be used including, for example, linear programming commands.
  • a computer system of the invention can further include a user interface capable of receiving a representation of one or more reactions.
  • a user interface of the invention can also be capable of sending at least one command for modifying the data structure, the constraint set or the commands for applying the constraint set to the data representation, or a combination thereof.
  • the interface can be a graphic user interface having graphical means for making selections such as menus or dialog boxes.
  • the interface can be arranged with layered screens accessible by making selections from a main screen.
  • the user interface can provide access to other databases useful in the invention such as a metabolic reaction database or links to other databases having information relevant to the reactions or reactants in the reaction network data structure or to a multicellular organism's physiology, including Homo sapiens physiology.
  • the user interface can display a graphical representation of a reaction network or the results of a simulation using a model of the invention.
  • this model can be tested by preliminary simulation.
  • preliminary simulation gaps in the network or “dead-ends” in which a metabolite can be produced but not consumed or where a metabolite can be consumed but not produced can be identified. Based on the results of preliminary simulations areas of the metabolic reconstruction that require an additional reaction can be identified. The determination of these gaps can be readily calculated through appropriate queries of the reaction network data structure and need not require the use of simulation strategies, however, simulation would be an alternative approach to locating such gaps.
  • the existing model is subjected to a series of functional tests to determine if it can perform basic requirements such as the ability to produce the required biomass constituents and generate predictions concerning the basic physiological characteristics of the particular cell type being modeled.
  • the majority of the simulations used in this stage of development will be single optimizations.
  • a single optimization can be used to calculate a single flux distribution demonstrating how metabolic resources are routed determined from the solution to one optimization problem.
  • An optimization problem can be solved using linear programming as demonstrated in the Examples below. The result can be viewed as a display of a flux distribution on a reaction map.
  • Temporary reactions can be added to the network to determine if they should be included into the model based on modeling/simulation requirements.
  • the model can be used to simulate activity of one or more reactions in a reaction network.
  • the results of a simulation can be displayed in a variety of formats including, for example, a table, graph, reaction network, flux distribution map or a phenotypic phase plane graph.
  • the invention provides a method for predicting a Homo sapiens physiological function.
  • the method includes the steps of (a) providing a data structure relating a plurality of Homo sapiens reactants to a plurality of Homo sapiens reactions, wherein each of the Homo sapiens reactions includes a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (b) providing a constraint set for the plurality of Homo sapiens reactions; (c) providing an objective function, and (d) determining at least one flux distribution that minimizes or maximizes the objective function when the constraint set is applied to the data structure, thereby predicting a Homo sapiens physiological function.
  • a method for predicting a Homo sapiens physiological function can include the steps of (a) providing a data structure relating a plurality of Homo sapiens reactants to a plurality of Homo sapiens reactions, wherein each of the Homo sapiens reactions includes a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating the substrate and the product, and wherein at least one of the reactions is a regulated reaction; (b) providing a constraint set for the plurality of reactions, wherein the constraint set includes a variable constraint for the regulated reaction; (c) providing a condition-dependent value to the variable constraint; (d) providing an objective function, and (e) determining at least one flux distribution that minimizes or maximizes the objective function when the constraint set is applied to the data structure, thereby predicting a Homo sapiens physiological function.
  • a method for predicting a physiological function of a multicellular organism includes: (a) providing a first data structure relating a plurality of reactants to a plurality of reactions from a first cell, each of said reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (b) providing a second data structure relating a plurality of reactants to a plurality of reactions from a second cell, each of said reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (c) providing a third data structure relating a plurality of intra-system reactants to a plurality of intra-system reactions between said first and second cells, each of said intra-system reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a substrate of the reaction,
  • the term “physiological function,” when used in reference to Homo sapiens is intended to mean an activity of an organism as a whole, including a multicellular organism and/or a Homo sapiens organism or cell as a whole.
  • An activity included in the term can be the magnitude or rate of a change from an initial state of, for example, two or more interacting cells or a Homo sapiens cell to a final state of the two or more interacting cells or the Homo sapiens cell.
  • An activity included in the term can be, for example, growth, energy production, redox equivalent production, biomass production, development, or consumption of carbon nitrogen, sulfur, phosphate, hydrogen or oxygen.
  • An activity can also be an output of a particular reaction that is determined or predicted in the context of substantially all of the reactions that affect the particular reaction in two or more interacting cells or a Homo sapiens cell, for example, or substantially all of the reactions that occur in a plurality of interacting cells such as a tissue, organ or organism, or substantially all of the reactions that occur in a Homo sapiens cell (e.g. muscle contraction).
  • a particular reaction included in the term are production of biomass precursors, production of a protein, production of an amino acid, production of a purine, production of a pyrimidine, production of a lipid, production of a fatty acid, production of a cofactor or transport of a metabolite.
  • a physiological function can include an emergent property which emerges from the whole but not from the sum of parts where the parts are observed in isolation (see for example, Palsson, Nat. Biotech 18:1147-1150 (2000)).
  • a physiological function of reactions within two or more interacting cells can be determined using phase plane analysis of flux distributions.
  • Phase planes are representations of the feasible set which can be presented in two or three dimensions.
  • two parameters that describe the growth conditions such as substrate and oxygen uptake rates can be defined as two axes of a two-dimensional space.
  • the optimal flux distribution can be calculated from a reaction network data structure and a set of constraints as set forth above for all points in this plane by repeatedly solving the linear programming problem while adjusting the exchange fluxes defining the two-dimensional space.
  • a finite number of qualitatively different metabolic pathway utilization patterns can be identified in such a plane, and lines can be drawn to demarcate these regions.
  • the demarcations defining the regions can be determined using shadow prices of linear optimization as described, for example in Chvatal, Linear Programming New York, W.H. Freeman and Co. (1983).
  • the regions are referred to as regions of constant shadow price structure.
  • the shadow prices define the intrinsic value of each reactant toward the objective function as a number that is either negative, zero, or positive and are graphed according to the uptake rates represented by the x and y axes. When the shadow prices become zero as the value of the uptake rates are changed there is a qualitative shift in the optimal reaction network.
  • phase plane One demarcation line in the phenotype phase plane is defined as the line of optimality (LO).
  • LO line represents the optimal relation between respective metabolic fluxes.
  • the LO can be identified by varying the x-axis flux and calculating the optimal y-axis flux with the objective function defined as the growth flux. From the phenotype phase plane analysis the conditions under which a desired activity is optimal can be determined. The maximal uptake rates lead to the definition of a finite area of the plot that is the predicted outcome of a reaction network within the environmental conditions represented by the constraint set. Similar analyses can be performed in multiple dimensions where each dimension on the plot corresponds to a different uptake rate. These and other methods for using phase plane analysis, such as those described in Edwards et al., Biotech Bioeng. 77:27-36(2002), can be used to analyze the results of a simulation using an in silico Homo sapiens model of the invention.
  • a physiological function of Homo sapiens can also be determined using a reaction map to display a flux distribution.
  • a reaction map of Homo sapiens can be used to view reaction networks at a variety of levels. In the case of a cellular metabolic reaction network a reaction map can contain the entire reaction complement representing a global perspective. Alternatively, a reaction map can focus on a particular region of metabolism such as a region corresponding to a reaction subsystem described above or even on an individual pathway or reaction.
  • the invention provides an apparatus that produces a representation of a Homo sapiens physiological function, wherein the representation is produced by a process including the steps of: (a) providing a data structure relating a plurality of Homo sapiens reactants to a plurality of Homo sapiens reactions, wherein each of the Homo sapiens reactions includes a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (b) providing a constraint set for the plurality of Homo sapiens reactions; (c) providing an objective function; (d) determining at least one flux distribution that minimizes or maximizes the objective function when the constraint set is applied to the data structure, thereby predicting a Homo sapiens physiological function, and (e) producing a representation of the activity of the one or more Homo sapiens reactions.
  • the invention provides an apparatus that produces a representation of two or more interacting cells, including a tissue, organ, physiological system or whole organism wherein data structures are provided relating a plurality of reactants to a plurality of reactions for each type of interacting cell and for one or more intra-system functions.
  • a constraint set is provided for the plurality of reactions for the plurality of data structures as well as an objective function that minimizes or maximizes an objective function when the constraint set is applied to predict a physiological function of the two or more interacting cells.
  • the apparatus produces a representation of the activity of one more reactions of the two or more interacting cells.
  • the methods of the invention can be used to determine the activity of a plurality of Homo sapiens reactions including, for example, biosynthesis of an amino acid, degradation of an amino acid, biosynthesis of a purine, biosynthesis of a pyrimidine, biosynthesis of a lipid, metabolism of a fatty acid, biosynthesis of a cofactor, transport of a metabolite and metabolism of an alternative carbon source.
  • the methods can be used to determine the activity of one or more of the reactions described above or listed in Table 1.
  • the methods of the invention can be used to determine a phenotype of a Homo sapiens mutant or aberrant cellular interaction between two or more cells.
  • the activity of one or more reactions can be determined using the methods described above, wherein the reaction network data structure lacks one or more gene-associated reactions that occur in Homo sapiens or in a multicellular organism or multicellular interaction.
  • the methods can be used to determine the activity of one or more reactions when a reaction that does not naturally occur in the model of multicellular interactions or in Homo sapiens , for example, is added to the reaction network data structure. Deletion of a gene can also be represented in a model of the invention by constraining the flux through the reaction to zero, thereby allowing the reaction to remain within the data structure.
  • simulations can be made to predict the effects of adding or removing genes to or from one or more cells within a multicellular interaction, including Homo sapiens and/or a Homo sapiens cell.
  • the methods can be particularly useful for determining the effects of adding or deleting a gene that encodes for a gene product that performs a reaction in a peripheral metabolic pathway.
  • a drug target or target for any other agent that affects a function of a multicellular interaction, including a Homo sapiens function can be predicted using the methods of the invention. Such predictions can be made by removing a reaction to simulate total inhibition or prevention by a drug or agent. Alternatively, partial inhibition or reduction in the activity a particular reaction can be predicted by performing the methods with altered constraints. For example, reduced activity can be introduced into a model of the invention by altering the a j or b j values for the metabolic flux vector of a target reaction to reflect a finite maximum or minimum flux value corresponding to the level of inhibition.
  • the effects of activating a reaction can be predicted by performing the methods with a reaction network data structure lacking a particular reaction or by altering the a j or b j values for the metabolic flux vector of a target reaction to reflect a maximum or minimum flux value corresponding to the level of activation.
  • the methods can be particularly useful for identifying a target in a peripheral metabolic pathway.
  • an enzyme or macromolecule that performs the reaction in the multicellular system or a gene that expresses the enzyme or macromolecule can be identified as a target for a drug or other agent.
  • a candidate compound for a target identified by the methods of the invention can be isolated or synthesized using known methods. Such methods for isolating or synthesizing compounds can include, for example, rational design based on known properties of the target (see, for example, DeCamp et al., Protein Engineering Principles and Practice , Ed. Cleland and Craik, Wiley-Liss, New York, pp.
  • a candidate drug or agent can be validated using an in silico model or method of multicellular interactions, including a Homo sapiens model or method of the invention.
  • the effect of a candidate drug or agent on physiological function can be predicted based on the activity for a target in the presence of the candidate drug or agent measured in vitro or in vivo.
  • This activity can be represented in an in silico model of the multicellular system by adding a reaction to the model, removing a reaction from the model or adjusting a constraint for a reaction in the model to reflect the measured effect of the candidate drug or agent on the activity of the reaction.
  • the methods of the invention can be used to determine the effects of one or more environmental components or conditions on an activity of, for example, a multicellular interaction, a tissue, organ, physiological function or a Homo sapiens cell.
  • an exchange reaction can be added to a reaction network data structure corresponding to uptake of an environmental component, release of a component to the environment, or other environmental demand.
  • the effect of the environmental component or condition can be further investigated by running simulations with adjusted a j or b j values for the metabolic flux vector of the exchange reaction target reaction to reflect a finite maximum or minimum flux value corresponding to the effect of the environmental component or condition.
  • the environmental component can be, for example an alternative carbon source or a metabolite that when added to the environment of a multicellular system, organism or Homo sapiens cell can be taken up and metabolized.
  • the environmental component can also be a combination of components present for example in a minimal medium composition.
  • the methods can be used to determine an optimal or minimal medium composition that is capable of supporting a particular activity of a multicellular interaction or system, including a particular activity of Homo sapiens.
  • the invention further provides a method for determining a set of environmental components to achieve a desired activity for Homo sapiens .
  • the method includes the steps of (a) providing a data structure relating a plurality of Homo sapiens reactants to a plurality of Homo sapiens reactions, wherein each of the Homo sapiens reactions includes a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating the substrate and the product; (b) providing a constraint set for the plurality of Homo sapiens reactions; (c) applying the constraint set to the data representation, thereby determining the activity of one or more Homo sapiens reactions (d) determining the activity of one or more Homo sapiens reactions according to steps (a) through (c), wherein the constraint set includes an upper or lower bound on the amount of an environmental component and (e) repeating steps (a) through (c) with a changed constraint set, wherein the activity determined in step
  • a method for determining a set of environmental components to achieve a desired activity for a multicellular interaction includes providing a plurality of data structures relating a plurality of reactants to a plurality of reactions for each type of interacting cell and for one or more intra-system functions; providing a constraint set for the plurality of reactions for the plurality of data structures as well as providing an objective function that minimizes or maximizes an objective function when the constraint set is applied to predict a physiological function of the two or more interacting cells; determining the activity of one or more reactions within two or more interacting cells using a constraint set having an upper or lower bound on the amount of an environmental component and repeating these steps until the activity is improved.
  • This example shows the construction of a universal Homo sapiens metabolic reaction database, a Homo sapiens core metabolic reaction database and a Homo sapiens muscle cell metabolic reaction database. This example also shows the iterative model building process used to generate a Homo sapiens core metabolic model and a Homo sapiens muscle cell metabolic model.
  • a universal Homo sapiens reaction database was prepared from the genome databases and biochemical literature.
  • the reaction database shown in Table 1 contains the following information:
  • a core metabolic reaction database was established, which included core metabolic reactions as well as some amino acid and fatty acid metabolic reactions, as described in Chapters 1, 3, 4, 7, 9, 10, 13, 17, 18 and 44 of J. G. Salway, Metabolism at a Glance, 2 nd ed., Blackwell Science, Malden, Mass. (1999).
  • the core metabolic reaction database included 211 unique reactions, accounting for 737 genes in the Homo sapiens genome.
  • the core metabolic reaction database was used, although not in its entirety, to create the core metabolic model described in Example II.
  • the core reaction database was expanded to include 446 unique reactions, accounting for 889 genes in the Homo sapiens genome.
  • This skeletal muscle metabolic reaction database was used to create the skeletal muscle metabolic model described in Example II.
  • the reactions were represented as a metabolic network data structure, or “stoichiometric input file.”
  • the core metabolic network data structure shown in Table 2 contains 33 reversible reactions, 31 non-reversible reactions, 97 matrix columns and 52 unique enzymes.
  • Each reaction in Table 2 is represented so as to indicate the substrate or substrates (a negative number) and the product or products (a positive number); the stoichiometry; the name of each reaction (the term following the zero); and whether the reaction is reversible (an R following the reaction name).
  • a metabolite that appears in the mitochondria is indicated by an “m,” and a metabolite that appears in the extracellular space is indicated by an “ex.”
  • a set of inputs and outputs has to be defined and the network objective function specified.
  • a non-zero uptake value for glucose was assigned and ATP production was maximized as the objective function, using the representation shown in Table 2.
  • the network's performance was examined by optimizing for the given objective function and the set of constraints defined in the input file, using flux balance analysis methods.
  • the model was refined in an iterative manner by examining the results of the simulation and implementing the appropriate changes.
  • This example shows how human metabolism can be accurately simulated using a Homo sapiens core metabolic model.
  • the human core metabolic reaction database shown in Table 3 was used in simulations of human core metabolism.
  • This reaction database contains a total of 65 reactions, covering the classic biochemical pathways of glycolysis, the pentose phosphate pathway, the tricitric acid cycle, oxidative phosphorylation, glycogen storage, the malate/aspartate shuttle, the glycerol phosphate shuttle, and plasma and mitochondrial membrane transporters.
  • the reaction network was divided into three compartments: the cytosol, mitochondria, and the extracellular space. The total number of metabolites in the network is 50, of which 35 also appear in the mitochondria. This core metabolic network accounts for 250 human genes.
  • This example shows how human muscle cell metabolism can be accurately simulated under various physiological and pathological conditions using a Homo sapiens muscle cell metabolic model.
  • the core metabolic model was extended to also include all the major reactions occurring in the skeletal muscle cell, adding new functions to the classical metabolic pathways found in the core model, such as fatty acid synthesis and ⁇ -oxidation, triacylglycerol and phospholipid formation, and amino acid metabolism. Simulations were performed using the muscle cell reaction database shown in Table 4. The biochemical reactions were again compartmentalized into cytosolic and mitochondrial compartments.
  • the skeletal muscle model was tested for utilization of various carbon sources available during various stages of exercise and food starvation (Table 8).
  • the by-product secretion of the network in an aerobic to anaerobic shift was qualitatively compared to physiological outcome of exercise and found to exhibit the same general features such as secretion of fermentative by-products and lowered energy yield.
  • the network behavior was also examined for five disease cases (Table 9).
  • the test cases were chosen based on their physiological relevance to the model's predictive capabilities.
  • McArdle's disease is marked by the impairment of glycogen breakdown.
  • Tarui's disease is characterized by a deficiency in phosphofructokinase.
  • the remaining diseases examined are marked by a deficiency of metabolic enzymes phosphoglycerate kinase, phosphoglycerate mutase, and lactate dehydrogenase.
  • This Example shows the construction and simulation of a multi-cellular model demonstrating the interactions between human adipocytes and monocytes.
  • a human metabolic network model was reconstructed using biochemical, physiological, and genomic data as described previously. Briefly, the central metabolic network was used as a template for the construction of cell-specific models by adding biochemical reactions known to occur in specific cell-types of interest based on genomic, biochemical, and/or physiological information. Other methods for reconstructing the cell-specific models included reconstructing all the biochemical pathways and biochemical reactions that occur in the human metabolism regardless of their tissue specificity and location within the cell in a database and then reconstructing cell-, tissue-, organ-specific models by separating reactions that occur in specified cells, tissues, and/or organs based on genomic, physiological, biochemical, and/or high throughput data such as gene expression, proteomics, metabolomics, and other types of “omic” data.
  • the metabolic network of the central human metabolism was constructed as a template and a starting point for reconstructing more specific cell models.
  • a central metabolic network for human metabolism a compendium of 1557 annotated human genes obtained from Kyoto Encyclopedia of Genes and Genomes KEGG, National Center for Biotechnology Information or NCBI, and the Universal Protein Resource or UniProt databases was used.
  • a compendium of 1557 annotated human genes obtained from Kyoto Encyclopedia of Genes and Genomes KEGG, National Center for Biotechnology Information or NCBI, and the Universal Protein Resource or UniProt databases was used.
  • a compendium of 1557 annotated human genes obtained from Kyoto Encyclopedia of Genes and Genomes KEGG, National Center for Biotechnology Information or NCBI, and the Universal Protein Resource or UniProt databases was used.
  • a compendium of 1557 annotated human genes obtained from Kyoto Encyclopedia of Genes and Genomes KEGG, National Center for Biotechnology Information or NCBI, and the Universal Protein Resource or UniProt databases was used.
  • the completed central metabolic network for human metabolism is shown in FIGS. 5-1 through 5 - 9 where dashed lines indicate organelle, cell, or system boundary.
  • the large dashed rectangle (black) represents the cytosolic membrane.
  • the large dashed circle (red) represents the mitochondrial membrane and small dashed circle (green) represents the endoplasmic reticulum membrane.
  • the human central metabolic network contains 80 reactions of which 25 are transporters and 60 unique metabolites 5.
  • FIG. 6 A representative example of a gene-protein-reaction association is shown in FIG. 6 where the open reading frame or ORF (7167) is associated to an mRNA transcript (TPI1). The transcript is then associated to a translated protein (Tpi1) that catalyzes a corresponding reaction (TPI).
  • Adipocytes are specialized cells for synthesizing and storing triacylglycerol.
  • Triacylglycerols (TAG's) are synthesized from dihydroxyacetone phosphate and fatty acids in white adipose tissue. Triacylglycerol synthesized in adipocytes can be hydrolyzed (or degraded) into fatty acids and glycerol via specialized pathways in the fat cells. The fatty acids that are released from triacylglycerol leave the cell and are transported to other cell types such as myocytes for energy production.
  • the fatty acid composition of triacylglycerol in human mammary adipose tissue has been experimentally measured (Raclot et al., 324:911-5 (1997)) and includes essential, non-essential, saturated, unsaturated, even-, and odd-chain fatty acids (Table 10).
  • TAG NEFA Relative Fatty acid (weight %) (weight %) mobilization C 12:0 0.50 ⁇ 0.07 0.45 ⁇ 0.06 0.88 ⁇ 0.02 C 14:0 3.08 ⁇ 0.13 2.94 ⁇ 0.15 0.94 ⁇ 0.01 C 14:1,n-7 0.03 ⁇ 0.00 0.03 ⁇ 0.00 1.07 ⁇ 0.14 C 14:1,n-5 0.20 ⁇ 0.01 0.19 ⁇ 0.02 0.96 ⁇ 0.03 C 15:0 0.33 ⁇ 0.02 0.35 ⁇ 0.02 1.05 ⁇ 0.02 C 16:0 22.79 ⁇ 0.56 23.51 ⁇ 0.74 1.02 ⁇ 0.01 C 16:1,n-9 0.54 ⁇ 0.01 0.42 ⁇ 0.02*** 0.77 ⁇ 0.01 C 16:1,n-7 2.77 ⁇ 0.21 3.69 ⁇ 0.34* 1.31 ⁇ 0.02 C
  • the adipocyte metabolic model was constructed by adding the non-essential saturated, unsaturated, even- and odd-chain fatty acid biosynthetic pathways to the central metabolic network for 21 of the fatty acids listed in Table 10. The remaining 13 essential fatty acids were supplied to the cell via the extra-cellular space, representing the nutritional intake from the environment. Pathway for biosynthesis of triacylglycerol (TAG) from all 34 fatty acids was included to account for the formation and storage of TAG in adipocytes. Reactions for hydrolysis of TAG into fatty acids were also included to represent TAG degradation. In addition to fatty acid synthesis and TAG biosynthesis and degradation, transport reactions were included to allow for the release of fatty acids from intra-cellular space to the environment.
  • TAG triacylglycerol
  • the metabolic model of an adipocyte cell contains a total of 198 reactions of which 63 are transporters.
  • the adipocyte cell model is shown in FIGS. 7-1 through 7 - 35 where dashed lines indicate organelle, cell, or system boundary.
  • the large dashed rectangle (yellow) represents the adipocyte cytosolic membrane.
  • the two large dashed circles (red) represent the mitochondrial membrane and the small dashed circle at the top (green) represents the endoplasmic reticulum membrane.
  • metabolic reactions were compartmentalized into extra-cellular, cytosolic, mitochondrial, and endoplasmic reticulum.
  • the extra-cellular space represents the environment outside the cell, which can include the space outside the body, connective tissues, and interstitial space between cells.
  • the energy required for muscle contraction is generally supplied by glucose, stored glycogen, phosphocreatine, and fatty acids.
  • the myocyte model was constructed by adding phosphocreatine kinase reaction, myosin-actin activation mechanism, and ⁇ -oxidation pathway to the central metabolic network.
  • Muscle contraction was represented by a sequential conversion of myoactin to myosin-ATP, myosin-ATP to myosin-ADP-P, myosin-ADP-P to myosin-actin-ADP-P complex, myosin-actin-ADP-P to myoactin, and subsequently the formation of muscle contraction as shown in FIG. 8 .
  • FIGS. 9-1 through 9 - 35 The complete reconstructed metabolic model for myocyte cell metabolism is shown in FIGS. 9-1 through 9 - 35 where dashed lines indicate organelle, cell, or system boundary.
  • the large dashed rectangle (brown) represents the myocyte cytosolic membrane.
  • the two large dashed circles (red) represent the mitochondrial membrane.
  • the medium sized dashed circle (purple) represents the peroxisomal membrane and the small dashed circle (green) represents the endoplasmic reticulum membrane.
  • the myocyte network contains a total of 205 reactions of which 46 are transport reactions. Reactions for utilizing phosphocreatine as well as selected pathways for ⁇ -oxidation of saturated, unsaturated, even- and odd-chain fatty acids and their intermediates were also included in the model and are shown in FIGS. 9-1 through 9 - 35 .
  • metabolic reactions were compartmentalized into extra-cellular, cytosolic, mitochondrial, peroxisomal, and endoplasmic reticulum.
  • the metabolic function of the two models of adipocyte and myocyte were integrated by reconstructing a model that includes all the metabolic reactions in the two individual cell types.
  • the interaction of the two cell types were then represented within an “intra-system” space, which represents the connective tissues such as blood, urine, and interstitial space, and an outside environment or “extra-system” space.
  • intra-system represents the connective tissues such as blood, urine, and interstitial space
  • extra-system an outside environment or extra-system space.
  • appropriate transport reactions were added to exchange metabolites across the extra-system boundary. Additional reactions also were added to balance metabolites in the intra-system space by including the bicarbonate and ammonia buffer systems as they function in the kidneys.
  • the combined adipocyte-myocyte model contains 430 reactions and 240 unique metabolites.
  • the complete reconstruction is shown in FIGS. 10-1 through 10 - 70 and a summary of the reactions is set forth in Table 11.
  • a substantially complete listing of all the reactions set forth in FIGS. 10-1 through 10 - 70 is set forth below in Table 15.
  • Model Reactions Transporters Compounds Central Metabolism 80 25 60 Adipocyte 198 63 150 Myocyte 205 46 167 Adipocyte-Myocyte 430 135 240
  • dashed lines again indicate organelle, cell, or system boundaries.
  • the outer most large dashed rectangle black
  • the two interior dashed rectangles represents the adipocyte cytosolic membrane (top, yellow) and the myocyte cytosolic membrane (bottom, brown).
  • the pair of larger dashed circles within the adipocyte and myocyte cytosol represent the mitochondrial membrane.
  • the medium sized dashed circle in the myocyte cytosol (purple) represents the peroxisomal membrane and small dashed circle within the adipocyte and myocyte cytosol (green) represent the endoplasmic reticulum membrane.
  • the computational and infrastructure requirements for producing the integrated multi-cellular model were assessed by examining the network properties of first, the cell-specific models, and then the integrated multi-cellular reconstruction.
  • the metabolic capabilities of the central human model was determined through computation of maximum yield of the 12 precursor metabolites per glucose. The results are shown in Table 12. In all cases, the network's yield was less or equal to the maximum theoretical values except for succinyl-CoA. In the case of succinyl-CoA, a higher yield was possible by incorporating CO 2 via pyruvate carboxylase reaction, PCm. In addition to precursor metabolite yields, the maximum ATP yield per mole of glucose was computed in the network. The maximum ATP yield for the central human metabolism was computed to be 31.5 mol ATP/mol glucose, which is consistent with previously calculated values (Vo et al., J. Biol. Chem. 279:39532-40. (2004)).
  • the biomass demand in living cells is a requirement for the production of biosynthetic components such as amino acids, lipids and other molecules that are needed to provide cell integrity, maintenance, and growth. All the biosynthetic components were made from the 12 precursor metabolites in the central metabolism shown in Table 12. The rate of growth and biomass maintenance in mammalian cells however is typically much lower than the rate of metabolic activities. Thus to represent the cells' biosynthetic requirement, a small flux demand was imposed for the production of the 12 precursor metabolites while maximizing for ATP. In the absence of experimental measurements, the capability of the network to meet the biosynthetic requirements was examined by constructing a reaction in which all the precursor metabolites were made simultaneously with stoichiometric coefficients of one as set forth in the reaction below:
  • Precursor Demand 3 pg[c]+accoa[m]+akg[m]+e 4 p[c]+f 6 p[c]+g 3 p[c]+g 6 p[c]+oaa[m]+pep[c]+pyr[c]+r 5 p[c]+succoa[m ] ⁇ (2) coa[m]
  • a main function of adipocyte is to synthesize, store, and hydrolyze triacylglycerols.
  • the stored TAG can be used to generate ATP during starvation or under high-energy demand conditions.
  • TAG hydrolysis results in the formation of fatty acids and glycerol in adipocyte.
  • Fatty acids are transported to other tissues such as the muscle tissue where they can be utilized to generate energy.
  • Glycerol is utilized further by the liver and other tissues where it is converted into glycerol phosphate and enters glycolytic pathway.
  • TAG synthesis was simulated by maximizing an internal demand for cytosolic triacylglycerol.
  • the maximum yield of triacylglycerol per glucose was computed to be 0.06 mol TAG/mol glucose, without any biomass demand.
  • the influx of all other carbon sources including glucose was constrained to zero and glycerol secretion, which is assumed to be taken up by the liver, was maximized.
  • a glycerol yield of 1 mol glycerol/mol TAG or 100% was computed.
  • TAG degradation pathway As shown in FIG. 11 , degradation of TAG was performed in the following three steps: (1) TRIGH_ac_HS_ub; (2) 12DGRH_ac_HS_ub, and (3) MGLYCH_ac_HS_ub). Glycerol generated as an end product of this pathway was transported out of the cell via a proton-coupled symport mechanism. TAG was hydrolyzed completely to fatty acids and glycerol in three steps and in each step one proton is released. Glycerol transport was coupled to one proton. Thus, a net amount of two protons were generated per mol TAG degraded.
  • YATP/glucose the maximum ATP yield on glucose (YATP/glucose) was computed in the adipocyte model.
  • YATP/glucose was 31.5 mol ATP/mol glucose.
  • the required energy in muscle tissue is generally supplied by glucose, stored glycogen, and phosphocreatine.
  • glucose stored glycogen
  • phosphocreatine During anaerobic exercise such as a sprint, for example, the blood vessels in the muscle tissue are compressed and the cells are isolated from the rest of the body (Devlin, supra). This compression restricts the oxygen supply to the tissue and enforces anaerobic energy metabolism in the cell. As a result, lactate is generated to balance the redox potential and must be secreted out of the cell. In the liver, lactate is converted into glucose. However, rapid muscle contraction and decreased blood flow to the muscle tissue cause lactate accumulation during anaerobic exercise and quickly impairs muscle contraction. During starvation or under high-energy demands, the glucose and glycogen storage of the muscle tissue quickly depletes and the energy storage in triacylglycerol molecules supplied by fatty cells is used to generate ATP.
  • phosphocreatine kinase reaction To simulate the muscle physiology at steady state, phosphocreatine kinase reaction, myosin-actin activation mechanism, and ⁇ -oxidation pathway were included in the central metabolic network.
  • the physiological function of muscle tissue was simulated by determining the maximum amount of contraction that is generated from the energy supplied by glucose, stored glycogen, phosphocreatine, and supplied fatty acids.
  • the metabolic capabilities of the myocyte model were assessed by first computing the maximum ATP yield on glucose.
  • YATP/glucose was 31.5 mol ATP/mol glucose.
  • the muscle contraction was also examined with glucose as the sole carbon source.
  • the muscle contraction was simulated also with stored glycogen and phosphocreatine as the energy source.
  • the maximum contraction for glycogen was computed to be 32.5 mol/mol glycogen in aerobic and 3 mol/mol glycogen in anaerobic condition.
  • the observed difference between the maximum contraction generated by glycogen in comparison to glucose arises from the absence of the phosphorylation or glucokinase step in the first step of glycolysis.
  • the results of glycogen versus glucose utilization are illustrated in FIG. 13 where the glycogen utilization pathway is shown as the thick bent arrow on the left (red) and the glucose utilization pathway is shown as the thick straight arrow on the right (blue).
  • the dashed circle (green) represents the endoplasmic reticulum membrane.
  • the maximum contraction from phosphocreatine under both aerobic and anaerobic conditions was computed to be 1 mol/mol phosphocreatine.
  • the energy generated from phosphocreatine is independent of the energy produced through oxidative phosphorylation and thus was computed to be the same in both aerobic and anaerobic conditions.
  • ⁇ -oxidative pathways in the myocyte tissue were examined by supplying the network with eicosanoate (n-C20:0), octadecenoate (C18:1, n-9), and pentadecanoate (C15:0) as examples of fatty acid oxidation of odd- and even-chain, and saturated and unsaturated fatty acids.
  • eicosanoate n-C20:0
  • octadecenoate C18:1, n-9
  • pentadecanoate C15:0
  • Table 13 demonstrate that maximum contraction in the myocyte model was 134 mol/mol for eicosanoate, 118.5 mol/mol for octadecenoate, and 98.5 mol/mol for pentadecanoate.
  • a unit of proton per fatty acid is required in the network to balance fatty acyl CoA formation in the cell as illustrated in the following reaction:
  • Fatty Acid CoA Ligase Fatty Acid + ATP + CoA ⁇ Fatty Acyl-CoA + AMP + PPi Adenylate Kinase: AMP + ATP (2) ADP Inorganic Diphosphatase: PPi + H 2 O ⁇ H + + (2) Pi Net: Fatty Acid + CoA + (2) ATP + H 2 O ⁇ Fatty Acyl-CoA + (2)O ADP + (2) Pi + H +
  • Muscle cells largely rely on their stored glycogen and phosphocreatine content. During aerobic exercise, however, glucose, glycogen, and phosphocreatine storage of muscle cells are depleted and energy generation in myocytes is achieved by fatty acid oxidation. Lipolysis or lipid degradation proceeds in muscle cells following the transfer of fatty acids from adipocytes to myocytes via blood.
  • Modeling of multi-cellular metabolism was performed using a constraint-based approach as described herein where the metabolic networks of adipocyte and myocyte were combined into a multi-cellular metabolic model as shown in FIGS. 10-1 through 10 - 70 .
  • the integrated model was assessed by computing the network energy requirements during anaerobic exercise such as that corresponding to a sprint and aerobic exercise such as that corresponding to a marathon. From a purely additive perspective, combining all of the reactions from the adipocyte model with those from the myocyte model was initially performed as a sufficient indicator for the combined network to compute integrated physiological results. However, with the two models strictly combined in this manner they were deficient at computing integrated functions such as those described below and, in particular, the results described in the “Muscle Contraction in a Marathon” section below. Addition of buffer systems for bicarbonate and ammonia allowed the combined model to function more efficiently and predictably. In retrospect, the inclusion of intra-system reactions is consistent with the role that, for example, the kidney plays in integrated metabolic physiology.
  • the maximum muscle contraction in an aerobic condition was computed by supplying the multi-cellular model with glucose, glycogen, and phosphocreatine as shown in Table 14.
  • muscle contraction was simulated under anaerobic condition by constraining the oxygen supply to zero.
  • Maximum contraction was computed to be the same as in the isolated myocyte model, as expected, demonstrating that the integrated model retains the functionalities observed in the single-cell model.
  • the total energy expenditure in a marathon is about 12,000 kJ or 2868 kcal, which is equivalent to burning about 750 g of carbohydrate or 330 g of fat (Stipanuk, supra). Since the total stored carbohydrate in the body is only about 400 to 900 g, the mobilized fatty acids from adipose tissue provide an important part of the supplied energy to the muscle cells in an aerobic metabolism and especially in a marathon.
  • the integrated model was first demonstrated to be able to synthesize and store triacylglycerol in the adipocyte compartment when supplied by glucose.
  • the integrated adipocyte-myocyte network was able to store TAG in adipocyte compartment. The results are shown in Table 14.
  • TAG degradation and fatty acid mobilization to the blood was simulated by maximizing glycerol secretion in the intra-system space generated from the stored TAG in adipocyte.
  • TAG hydrolysis was simulated with the integrated adipocyte-myocyte model and maximum glycerol secretion rate was shown to be the same.
  • Oxidative phosphorylation PATH hsa00190 4535 MTND1 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3 4636 MTND2 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3 4537 MTND3 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3 4538 MTND4 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3 4539 MTND4L NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3 4240 MINDS NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3 4541 MTND8 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3 4541 MTND8 NA
  • Epidermal keratinocyte differentiated epidermal cell
  • Epidermal basal cell Keratinocyte of fingernails and toenails Nail bed basal cell (stem cell)
  • Medullary hair shaft cell Cuticular hair shaft cell Cuticular hair root sheath cell Hair root sheath cell of Huxley's layer Hair root sheath cell of Henle's layer
  • External hair root sheath cell Hair matrix cell (stem cell)
  • Wet stratified barrier epithelial cells Surface epithelial cell of stratified squamous epithelium of cornea, tongue, oral cavity, esophagus, anal canal, distal urethra and vagina basal cell (stem cell) of epithelia of cornea, tongue, oral cavity, esophagus, anal canal, distal urethra and vagina Urinary epithelium cell (lining urinary bladder and urinary ducts

Abstract

The invention provides a computer readable medium or media, having: (a) a first data structure relating a plurality of reactants to a plurality of reactions from a first cell, each of said reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (b) a second data structure relating a plurality of reactants to a plurality of reactions from a second cell, each of said reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (c) a third data structure relating a plurality of intra-system reactants to a plurality of intra-system reactions between said first and second cells, each of said intra-system reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (d) a constraint set for said plurality of reactions for said first, second and third data structures, and (e) commands for determining at least one flux distribution that minimizes or maximizes an objective function when said constraint set is applied to said first and second data structures, wherein said at least one flux distribution is predictive of a physiological function of said first and second cells. The first, second and third data structures also can include a plurality of data structures. Additionally provided is a method for predicting a physiological function of a multicellular organism. The method includes: (a) providing a first data structure relating a plurality of reactants to a plurality of reactions from a first cell, each of said reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (b) providing a second data structure relating a plurality of reactants to a plurality of reactions from a second cell, each of said reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (c) providing a third data structure relating a plurality of intra-system reactants to a plurality of intra-system reactions between said first and second cells, each of said intra-system reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (d) providing a constraint set for said plurality of reactions for said first, second and third data structures; (e) providing an objective function, and (f) determining at least one flux distribution that minimizes or maximizes an objective function when said constraint set is applied to said first and second data structures, wherein said at least one flux distribution is predictive of a physiological function of said first and second cells.

Description

  • This application is a continuation under 35 U.S.C. §120 of U.S. patent application Ser. No. 11/188,136, filed Jul. 21, 2005, now U.S. Pat. No. 8,949,032, which is a continuation-in-part of U.S. patent application Ser. No. 10/402,854, filed Mar. 27, 2003, now U.S. Pat. No. 8,229,673, which claims benefit of the filing date of U.S. Provisional Application No. 60/368,588, filed Mar. 29, 2002, the entire contents of each of which is incorporated herein by reference.
  • BACKGROUND OF THE INVENTION
  • This invention relates generally to analysis of the activity of chemical reaction networks and, more specifically, to computational methods for simulating and predicting the activity of multiple interacting reaction networks.
  • Therapeutic agents, including drugs and gene-based agents, are being rapidly developed by the pharmaceutical industry with the goal of preventing or treating human disease. Dietary supplements, including herbal products, vitamins and amino acids, are also being developed and marketed by the nutraceutical industry. Because of the complexity of the biochemical reaction networks in and between human cells, even relatively minor perturbations caused by a therapeutic agent or a dietary component in the abundance or activity of a particular target, such as a metabolite, gene or protein, can affect hundreds of biochemical reactions. These perturbations can lead to desirable therapeutic effects, such as cell stasis or cell death in the case of cancer cells or other pathologically hyperproliferative cells. However, these perturbations can also lead to undesirable side effects, such as production of toxic byproducts, if the systemic effects of the perturbations are not taken into account.
  • Current approaches to drug and nutraceutical development do not take into account the effect of a perturbation in a molecular target on systemic cellular behavior. In order to design effective methods of repairing, engineering or disabling cellular activities, it is essential to understand human cellular behavior from an integrated perspective.
  • Cellular metabolism, which is an example of a process involving a highly integrated network of biochemical reactions, is fundamental to all normal cellular or physiological processes, including homeostatis, proliferation, differentiation, programmed cell death (apoptosis) and motility. Alterations in cellular metabolism characterize a vast number of human diseases. For example, tissue injury is often characterized by increased catabolism of glucose, fatty acids and amino acids, which, if persistent, can lead to organ dysfunction. Conditions of low oxygen supply (hypoxia) and nutrient supply, such as occur in solid tumors, result in a myriad of adaptive metabolic changes including activation of glycolysis and neovascularization. Metabolic dysfunctions also contribute to neurodegenerative diseases, cardiovascular disease, neuromuscular diseases, obesity and diabetes. Currently, despite the importance of cellular metabolism to normal and pathological processes, a detailed systemic understanding of cellular metabolism in human cells is currently lacking.
  • Thus, there exists a need for models that describe interacting reaction networks within and between cells, including core metabolic reaction networks and metabolic reaction networks in specialized cell types, which can be used to simulate different aspects of multicellular behavior under physiological, pathological and therapeutic conditions. The present invention satisfies this need, and provides related advantages as well.
  • SUMMARY OF THE INVENTION
  • The invention provides a computer readable medium or media, having: (a) a first data structure relating a plurality of reactants to a plurality of reactions from a first cell, each of said reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (b) a second data structure relating a plurality of reactants to a plurality of reactions from a second cell, each of said reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (c) a third data structure relating a plurality of intra-system reactants to a plurality of intra-system reactions between said first and second cells, each of said intra-system reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (d) a constraint set for said plurality of reactions for said first, second and third data structures, and (e) commands for determining at least one flux distribution that minimizes or maximizes an objective function when said constraint set is applied to said first and second data structures, wherein said at least one flux distribution is predictive of a physiological function of said first and second cells. The first, second and third data structures also can include a plurality of data structures. Additionally provided is a method for predicting a physiological function of a multicellular organism. The method includes: (a) providing a first data structure relating a plurality of reactants to a plurality of reactions from a first cell, each of said reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (b) providing a second data structure relating a plurality of reactants to a plurality of reactions from a second cell, each of said reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (c) providing a third data structure relating a plurality of intra-system reactants to a plurality of intra-system reactions between said first and second cells, each of said intra-system reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (d) providing a constraint set for said plurality of reactions for said first, second and third data structures; (e) providing an objective function, and (f) determining at least one flux distribution that minimizes or maximizes an objective function when said constraint set is applied to said first and second data structures, wherein said at least one flux distribution is predictive of a physiological function of said first and second cells.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • FIG. 1 shows a schematic representation of a hypothetical metabolic network.
  • FIG. 2 shows mass balance constraints and flux constraints (reversibility constraints) that can be placed on the hypothetical metabolic network shown in FIG. 1.
  • FIG. 3 shows the stoichiometric matrix (S) for the hypothetical metabolic network shown in FIG. 1.
  • FIG. 4 shows, in Panel A, an exemplary biochemical reaction network and in Panel B, an exemplary regulatory control structure for the reaction network in panel A.
  • FIGS. 5-1 through 5-9 show a metabolic network of central human metabolism.
  • FIG. 6 shows an example of a gene-protein-reaction association for trios-phosphate isomerase.
  • FIGS. 7-1 through 7-35 show a metabolic network of adipocyte metabolism.
  • FIG. 8 shows muscle contraction in a myocyte metabolic model.
  • FIGS. 9-1 through 9-35 show a metabolic network of myocyte metabolism.
  • FIGS. 10-1 through 10-70 show a metabolic network of coupled adipocyte-myocyte metabolism.
  • FIG. 11 shows triacylglycerol degradation in an adipocyte model.
  • FIG. 12 shows the impairment of muscle contraction as a result of lactate accumulation during anaerobic exercise. Time is in arbitrary unit. Concentration and yield of lactate (YLac) production are in mol/mol glucose.
  • FIG. 13 shows glycogen utilization versus (highlighted on the left) glucose utilization (highlighted on the right) in myocyte.
  • DETAILED DESCRIPTION OF THE INVENTION
  • The present invention provides in silico models that describe the interconnections between genes in the Homo sapiens genome and their associated reactions and reactants. The invention also provides in silico models that describe interconnections between different biochemical networks within a cell as well as between cells. The interconnections among different biochemical networks between cells can describe interactions between, for example, groups of cells including cells within different locations, tissues, organs or between cells carrying out different functions of a multicellular organism. Therefore, the models can be used to simulate different aspects of the cellular behavior of a cell derived from a multicellular organism, including a human cell, as well as be used to simulate different aspects of cellular behavioral interactions of groups of cells. Such groups of cells include, for example, eukaryotic cells, such as those of the same tissue type or colonies of prokaryotic cells, or different types of eukaryotic cells derived from the same or different tissue types from a multicellular organism. The different aspects of cellular behavior, including cellular behavioral interactions, can be simulated under different normal, pathological and therapeutic conditions, thereby providing valuable information for therapeutic, diagnostic and research applications. One advantage of the models of the invention is that they provide a holistic approach to simulating and predicting the activity of multicellular organisms, cellular interactions and individual cells, including the activity of Homo sapiens cells. Therefore, the models and methods can be used to simulate the activity of multiple interacting cells, including organs, physiological systems and whole body metabolism for practical diagnostic and therapeutic purposes.
  • In one embodiment, the invention is exemplified by reference to a metabolic model of a Homo sapien cell. This in silico model of an eukaryotic cell describes the cellular behavior resulting from two or more interacting networks because it can contain metabolic, regulatory and other network interactions, as described below. The models and methods of the invention applicable to the production and use of a cellular model containing two or more interacting networks also are applicable to the production and use of a multi-network model where the two or more networks are separated between compartments such as cells or tissues of a multicellular organism. Therefore, a Homo sapien or other eukaryotic cell model of the invention exemplifies application of the models and methods of the invention to models that describe the interaction of multiple biochemical networks between and among cells of a tissue, organ, physiological system or whole organism.
  • In another embodiment, the Homo sapiens metabolic models of the invention can be used to determine the effects of changes from aerobic to anaerobic conditions, such as occurs in skeletal muscles during exercise or in tumors, or to determine the effect of various dietary changes. The Homo sapiens metabolic models can also be used to determine the consequences of genetic defects, such as deficiencies in metabolic enzymes such as phosphofructokinase, phosphoglycerate kinase, phosphoglycerate mutase, lactate dehydrogenase and adenosine deaminase.
  • In a further embodiment, the invention provides a model of multicellular interactions that includes the network reconstruction, characteristics and simulation performance of an integrated two cell model of human adipocyte and myocyte cells. This multicellular model also included an intra-system biochemical network for extracellular physiological systems. The model was generated by reconstructing each of the component biochemical networks within the cells and combining them together with the addition of the intra-system biochemical network and achieved accurate predictive performance of the two cell types under different physiological conditions. Such multicellular metabolic models can be employed for the same determinations as described above for the Homo sapiens metabolic models. The determinations can be performed at the cellular, tissue, physiological system or organism level.
  • The multicellular and Homo sapiens metabolic models also can be used to choose appropriate targets for drug design. Such targets include genes, proteins or reactants, which when modulated positively or negatively in a simulation produce a desired therapeutic result. The models and methods of the invention can also be used to predict the effects of a therapeutic agent or dietary supplement on a cellular function of interest. Likewise, the models and methods can be used to predict both desirable and undesirable side effects of the therapeutic agent on an interrelated cellular function in the target cell, as well as the desirable and undesirable effects that may occur in other cell types. Thus, the models and methods of the invention can make the drug development process more rapid and cost effective than is currently possible.
  • The multicellular and Homo sapiens metabolic models also can be used to predict or validate the assignment of particular biochemical reactions to the enzyme-encoding genes found in the genome, and to identify the presence of reactions or pathways not indicated by current genomic data. Thus, the models can be used to guide the research and discovery process, potentially leading to the identification of new enzymes, medicines or metabolites of clinical importance.
  • The models of the invention are based on a data structure relating a plurality of reactants to a plurality of reactions, wherein each of the reactions includes a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating the substrate and the product. The reactions included in the data structure can be those that are common to all or most cells or to a particular type or species of cell, including Homo sapiens cells, such as core metabolic reactions, or reactions specific for one or more given cell type.
  • As used herein, the term “reaction” is intended to mean a conversion that consumes a substrate or forms a product that occurs in or by a cell. The term can include a conversion that occurs due to the activity of one or more enzymes that are genetically encoded by a genome of the cell. The term can also include a conversion that occurs spontaneously in a cell. When used in reference to a Homo sapiens reaction, the term is intended to mean a conversion that consumes a substrate or forms a product that occurs in or by a Homo sapiens cell. Conversions included in the term include, for example, changes in chemical composition such as those due to nucleophilic or electrophilic addition, nucleophilic or electrophilic substitution, elimination, isomerization, deamination, phosphorylation, methylation, reduction, oxidation or changes in location such as those that occur due to a transport reaction that moves a reactant from one cellular compartment to another. In the case of a transport reaction, the substrate and product of the reaction can be chemically the same and the substrate and product can be differentiated according to location in a particular cellular compartment. Thus, a reaction that transports a chemically unchanged reactant from a first compartment to a second compartment has as its substrate the reactant in the first compartment and as its product the reactant in the second compartment. It will be understood that when used in reference to an in silico model or data structure, a reaction is intended to be a representation of a chemical conversion that consumes a substrate or produces a product.
  • As used herein, the term “reactant” is intended to mean a chemical that is a substrate or a product of a reaction that occurs in or by a cell. The term can include substrates or products of reactions performed by one or more enzymes encoded by a genome, reactions occurring in cells or organisms that are performed by one or more non-genetically encoded macromolecule, protein or enzyme, or reactions that occur spontaneously in a cell. When used in reference to a Homo sapiens reactant, the term is intended to mean a chemical that is a substrate or product of a reaction that occurs in or by a Homo sapiens cell. Metabolites are understood to be reactants within the meaning of the term. It will be understood that when used in reference to an in silico model or data structure, a reactant is intended to be a representation of a chemical that is a substrate or a product of a reaction that occurs in or by a cell.
  • As used herein the term “substrate” is intended to mean a reactant that can be converted to one or more products by a reaction. The term can include, for example, a reactant that is to be chemically changed due to nucleophilic or electrophilic addition, nucleophilic or electrophilic substitution, elimination, isomerization, deamination, phosphorylation, methylation, reduction, oxidation or that is to change location such as by being transported across a membrane or to a different compartment.
  • As used herein, the term “product” is intended to mean a reactant that results from a reaction with one or more substrates. The term can include, for example, a reactant that has been chemically changed due to nucleophilic or electrophilic addition, nucleophilic or electrophilic substitution, elimination, isomerization, deamination, phosphorylation, methylation, reduction or oxidation or that has changed location such as by being transported across a membrane or to a different compartment.
  • As used herein, the term “stoichiometric coefficient” is intended to mean a numerical constant correlating the number of one or more reactants and the number of one or more products in a chemical reaction. Typically, the numbers are integers as they denote the number of molecules of each reactant in an elementally balanced chemical equation that describes the corresponding conversion. However, in some cases the numbers can take on non-integer values, for example, when used in a lumped reaction or to reflect empirical data.
  • As used herein, the term “plurality,” when used in reference to reactions or reactants including Homo sapiens reactions or reactants, is intended to mean at least 2 reactions or reactants. The term can include any number of reactions or reactants in the range from 2 to the number of naturally occurring reactants or reactions for a particular of cell or cells. Thus, the term can include, for example, at least 10, 20, 30, 50, 100, 150, 200, 300, 400, 500, 600 or more reactions or reactants. The number of reactions or reactants can be expressed as a portion of the total number of naturally occurring reactions for a particular cell or cells including a Homo sapiens cell or cells, such as at least 20%, 30%, 50%, 60%, 75%, 90%, 95% or 98% of the total number of naturally occurring reactions that occur in a particular Homo sapiens cell.
  • Similarly, the term “plurality,” when used in reference to data structures, is intended to mean at least 2 data structures. The term can include any number of data structures in the range from 2 to the number of naturally occurring biochemical networks for a particular subsystem, system, intracellular system, cellular compartment, organelle, extra-cellular space, cytosol, mitochondrion, nucleus, endoplasmic reticulum, group of cells, tissue, organ or organism. Therefore, the term can include, for example, at least about 3, 4, 5, 6, 7, 8, 9, 10, 25, 20, 25, 50, 100 or more biochemical networks. The term also can be expressed as a portion of the total number of naturally occurring networks for any of the particular categories above occurring in prokaryotic or eukaryotic cells including Homo sapiens.
  • As used herein, the term “data structure” is intended to mean a physical or logical relationship among data elements, designed to support specific data manipulation functions. The term can include, for example, a list of data elements that can be added combined or otherwise manipulated such as a list of representations for reactions from which reactants can be related in a matrix or network. The term can also include a matrix that correlates data elements from two or more lists of information such as a matrix that correlates reactants to reactions. Information included in the term can represent, for example, a substrate or product of a chemical reaction, a chemical reaction relating one or more substrates to one or more products, a constraint placed on a reaction, or a stoichiometric coefficient.
  • As used herein, the term “constraint” is intended to mean an upper or lower boundary for a reaction. A boundary can specify a minimum or maximum flow of mass, electrons or energy through a reaction. A boundary can further specify directionality of a reaction. A boundary can be a constant value such as zero, infinity, or a numerical value such as an integer. Alternatively, a boundary can be a variable boundary value as set forth below.
  • As used herein, the term “variable,” when used in reference to a constraint is intended to mean capable of assuming any of a set of values in response to being acted upon by a constraint function. The term “function,” when used in the context of a constraint, is intended to be consistent with the meaning of the term as it is understood in the computer and mathematical arts. A function can be binary such that changes correspond to a reaction being off or on. Alternatively, continuous functions can be used such that changes in boundary values correspond to increases or decreases in activity. Such increases or decreases can also be binned or effectively digitized by a function capable of converting sets of values to discreet integer values. A function included in the term can correlate a boundary value with the presence, absence or amount of a biochemical reaction network participant such as a reactant, reaction, enzyme or gene. A function included in the term can correlate a boundary value with an outcome of at least one reaction in a reaction network that includes the reaction that is constrained by the boundary limit. A function included in the term can also correlate a boundary value with an environmental condition such as time, pH, temperature or redox potential.
  • As used herein, the term “activity,” when used in reference to a reaction, is intended to mean the amount of product produced by the reaction, the amount of substrate consumed by the reaction or the rate at which a product is produced or a substrate is consumed. The amount of product produced by the reaction, the amount of substrate consumed by the reaction or the rate at which a product is produced or a substrate is consumed can also be referred to as the flux for the reaction.
  • As used herein, the term “activity,” when used in reference to a Homo sapiens cell or a multicellular interaction, is intended to mean the magnitude or rate of a change from an initial state to a final state. The term can include, for example, the amount of a chemical consumed or produced by a cell, the rate at which a chemical is consumed or produced by a cell, the amount or rate of growth of a cell or the amount of or rate at which energy, mass or electrons flow through a particular subset of reactions.
  • The invention provides a computer readable medium, having a data structure relating a plurality of Homo sapiens reactants to a plurality of Homo sapiens reactions, wherein each of the Homo sapiens reactions includes a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating the substrate and the product.
  • Also provided is a computer readable medium or media, having: (a) a first data structure relating a plurality of reactants to a plurality of reactions from a first cell, each of said reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (b) a second data structure relating a plurality of reactants to a plurality of reactions from a second cell, each of said reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (c) a third data structure relating a plurality of intra-system reactants to a plurality of intra-system reactions between said first and second cells, each of said intra-system reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (c) a constraint set for said plurality of reactions for said first, second and third data structures, and (d) commands for determining at least one flux distribution that minimizes or maximizes an objective function when said constraint set is applied to said first and second data structures, wherein said at least one flux distribution is predictive of a physiological function of said first and second cells.
  • Depending on the application, the plurality of reactions for any of a multicellular, multi-network or single cell model or method of the invention, including a Homo sapiens cell model or method, can include reactions selected from core metabolic reactions or peripheral metabolic reactions. As used herein, the term “core,” when used in reference to a metabolic pathway, is intended to mean a metabolic pathway selected from glycolysis/gluconeogenesis, the pentose phosphate pathway (PPP), the tricarboxylic acid (TCA) cycle, glycogen storage, electron transfer system (ETS), the malate/aspartate shuttle, the glycerol phosphate shuttle, and plasma and mitochondrial membrane transporters. As used herein, the term “peripheral,” when used in reference to a metabolic pathway, is intended to mean a metabolic pathway that includes one or more reactions that are not a part of a core metabolic pathway.
  • A plurality of reactants can be related to a plurality of reactions in any data structure that represents, for each reactant, the reactions by which it is consumed or produced. Thus, the data structure, which is referred to herein as a “reaction network data structure,” serves as a representation of a biological reaction network or system. An example of a reaction network that can be represented in a reaction network data structure of the invention is the collection of reactions that constitute the core metabolic reactions of Homo sapiens, or the metabolic reactions of a skeletal muscle cell, as shown in the Examples. Further examples of reaction networks that can be represented in a reaction network data structure of the invention are the collection of reactions that constitute the core metabolic reactions and the triacylglycerol (TAG) biosynthetic pathways of an adipocyte cell; the core metabolic reactions and the energy and contractile reactions of a myocyte cell, and the intra-system reactions that supply buffering functions of the kidney.
  • The choice of reactions to include in a particular reaction network data structure, from among all the possible reactions that can occur in multicellular organisms or among multicellular interactions, including human cells, depends on the cell type or types and the physiological, pathological or therapeutic condition being modeled, and can be determined experimentally or from the literature, as described further below.
  • The reactions to be included in a particular network data structure of a multicellular interaction can be determined experimentally using, for example, gene or protein expression profiles, where the molecular characteristics of the cell can be correlated to the expression levels. The expression or lack of expression of genes or proteins in a cell type can be used in determining whether a reaction is included in the model by association to the expressed gene(s) and or protein(s). Thus, it is possible to use experimental technologies to determine which genes and/or proteins are expressed in a specific cell type, and to further use this information to determine which reactions are present in the cell type of interest. In this way a subset of reactions from all of those reactions that can occur in human cells are selected to comprise the set of reactions that represent a specific cell type. cDNA expression profiles have been demonstrated to be useful, for example, for classification of breast cancer cells (Sorlie et al., Proc. Natl. Acad. Sci. U.S.A. 98(19):10869-10874 (2001)).
  • The methods and models of the invention can be applied to any multicellular interaction as well as to any Homo sapiens cell type at any stage of differentiation, including, for example, embryonic stem cells, hematopoietic stem cells, differentiated hematopoietic cells, skeletal muscle cells, cardiac muscle cells, smooth muscle cells, skin cells, nerve cells, kidney cells, pulmonary cells, liver cells, adipocytes and endocrine cells (e.g. beta islet cells of the pancreas, mammary gland cells, adrenal cells, and other specialized hormone secreting cells). Similarly, the methods and models of the invention can be applied to any interaction between any of these cell types, including two or more of the same cell type or two or more different cell types. Described below in Example IV is an example of the interactions that occur between myocyte cells and adipocyte cells during different physiological conditions.
  • The methods and models of the invention can be applied to normal cells, pathological cells as well as to combinations of interactions between normal cells, interactions between pathological cells or interactions between normal and pathological cells. Normal cells that exhibit a variety of physiological activities of interest, including homeostasis, proliferation, differentiation, apoptosis, contraction and motility, can be modeled. Pathological cells can also be modeled, including cells that reflect genetic or developmental abnormalities, nutritional deficiencies, environmental assaults, infection (such as by bacteria, viral, protozoan or fungal agents), neoplasia, aging, altered immune or endocrine function, tissue damage, or any combination of these factors. The pathological cells can be representative of any type of pathology, such as a human pathology, including, for example, various metabolic disorders of carbohydrate, lipid or protein metabolism, obesity, diabetes, cardiovascular disease, fibrosis, various cancers, kidney failure, immune pathologies, neurodegenerative diseases, and various monogenetic metabolic diseases described in the Online Mendelian Inheritance in Man database (Center for Medical Genetics, Johns Hopkins University (Baltimore, Md.) and National Center for Biotechnology Information, National Library of Medicine (Bethesda, Md.)).
  • The methods and models of the invention can also be applied to cells or organisms undergoing therapeutic perturbations, such as cells treated with drugs that target participants in a reaction network or cause an effect on an interactive reaction network, cells or tissues treated with gene-based therapeutics that increase or decrease expression of an encoded protein, and cells or tissues treated with radiation. As used herein, the term “drug” refers to a compound of any molecular nature with a known or proposed therapeutic function, including, for example, small molecule compounds, peptides and other macromolecules, peptidomimetics and antibodies, any of which can optionally be tagged with cytostatic, targeting or detectable moieties. The term “gene-based therapeutic” refers to nucleic acid therapeutics, including, for example, expressible genes with normal or altered protein activity, antisense compounds, ribozymes, DNAzymes, RNA interference compounds (RNAi) and the like. The therapeutics can target any reaction network participant, in any cellular location, including participants in extracellular, cell surface, cytoplasmic, mitochondrial and nuclear locations. Experimental data that are gathered on the response of cells, tissues, or interactions thereof, to therapeutic treatment, such as alterations in gene or protein expression profiles, can be used to tailor a network or a combination of networks for a pathological state of a particular cell type.
  • The methods and models of the invention can be applied to cells, tissues and physiological systems, including Homo sapiens cells, tissues and physiological systems, as they exist in any form, such as in primary cell isolates or in established cell lines, or in the whole body, in intact organs or in tissue explants. Accordingly, the methods and models can take into account intercellular communications and/or inter-organ communications, the effect of adhesion to a substrate or neighboring cells (such as a stem cell interacting with mesenchymal cells or a cancer cell interacting with its tissue microenvironment, or beta-islet cells without normal stroma), and other interactions relevant to multicellular systems.
  • The reactants to be used in a reaction network data structure of the invention can be obtained from or stored in a compound database. As used herein, the term “compound database” is intended to mean a computer readable medium or media containing a plurality of molecules that includes substrates and products of biological reactions. The plurality of molecules can include molecules found in multiple organisms, thereby constituting a universal compound database. Alternatively, the plurality of molecules can be limited to those that occur in a particular organism, thereby constituting an organism-specific compound database. Each reactant in a compound database can be identified according to the chemical species and the cellular compartment in which it is present. Thus, for example, a distinction can be made between glucose in the extracellular compartment versus glucose in the cytosol. Additionally each of the reactants can be specified as a metabolite of a primary or secondary metabolic pathway. Although identification of a reactant as a metabolite of a primary or secondary metabolic pathway does not indicate any chemical distinction between the reactants in a reaction, such a designation can assist in visual representations of large networks of reactions.
  • As used herein, the term “compartment” is intended to mean a subdivided region containing at least one reactant, such that the reactant is separated from at least one other reactant in a second region. A subdivided region included in the term can be correlated with a subdivided region of a cell. Thus, a subdivided region included in the term can be, for example, the intracellular space of a cell; the extracellular space around a cell; the periplasmic space, the interior space of an organelle such as a mitochondrium, endoplasmic reticulum, Golgi apparatus, vacuole or nucleus; or any subcellular space that is separated from another by a membrane or other physical barrier. For example, a mitochondrial compartment is a subdivided region of the intracellular space of a cell, which in turn, is a subdivided region of a cell or tissue. A subdivided region also can include, for example, different regions or systems of a tissue, organ or physiological system of an organism. Subdivided regions can also be made in order to create virtual boundaries in a reaction network that are not correlated with physical barriers. Virtual boundaries can be made for the purpose of segmenting the reactions in a network into different compartments or substructures.
  • As used herein, the term “substructure” is intended to mean a portion of the information in a data structure that is separated from other information in the data structure such that the portion of information can be separately manipulated or analyzed. The term can include portions subdivided according to a biological function including, for example, information relevant to a particular metabolic pathway such as an internal flux pathway, exchange flux pathway, central metabolic pathway, peripheral metabolic pathway, or secondary metabolic pathway. The term can include portions subdivided according to computational or mathematical principles that allow for a particular type of analysis or manipulation of the data structure.
  • The reactions included in a reaction network data structure can be obtained from a metabolic reaction database that includes the substrates, products, and stoichiometry of a plurality of metabolic reactions of Homo sapiens, other multicellular organisms or single cell organisms that exhibit biochemical or physiological interactions. The reactants in a reaction network data structure can be designated as either substrates or products of a particular reaction, each with a stoichiometric coefficient assigned to it to describe the chemical conversion taking place in the reaction. Each reaction is also described as occurring in either a reversible or irreversible direction. Reversible reactions can either be represented as one reaction that operates in both the forward and reverse direction or be decomposed into two irreversible reactions, one corresponding to the forward reaction and the other corresponding to the backward reaction.
  • Reactions included in a reaction network data structure can include intra-system or exchange reactions. Intra-system reactions are the chemically and electrically balanced interconversions of chemical species and transport processes, which serve to replenish or drain the relative amounts of certain metabolites. These intra-system reactions can be classified as either being transformations or translocations. A transformation is a reaction that contains distinct sets of compounds as substrates and products, while a translocation contains reactants located in different compartments. Thus a reaction that simply transports a metabolite from the extracellular environment to the cytosol, without changing its chemical composition is solely classified as a translocation, while a reaction that takes an extracellular substrate and converts it into a cytosolic product is both a translocation and a transformation. Further, intra-system reactions can include reactions representing one or more biochemical or physiological functions of an independent cell, tissue, organ or physiological system. For example, the buffering function of the kidneys for the hematopoietic system and intra-cellular environments can be represented as intra-system reactions and be included in a multicellular interaction model either as an independent reaction network or merged with one or more reaction networks of the constituent cells.
  • Exchange reactions are those which constitute sources and sinks, allowing the passage of metabolites into and out of a compartment or across a hypothetical system boundary. These reactions are included in a model for simulation purposes and represent the metabolic demands placed on Homo sapiens. While they may be chemically balanced in certain cases, they are typically not balanced and can often have only a single substrate or product. As a matter of convention the exchange reactions are further classified into demand exchange and input/output exchange reactions.
  • The metabolic demands placed on a multicellular or Homo sapiens metabolic reaction network can be readily determined from the dry weight composition of the cell, cells, tissue, organ or organism which is available in the published literature or which can be determined experimentally. The uptake rates and maintenance requirements for Homo sapiens cells can also be obtained from the published literature or determined experimentally.
  • Input/output exchange reactions are used to allow extracellular reactants to enter or exit the reaction network represented by a model of the invention. For each of the extracellular metabolites a corresponding input/output exchange reaction can be created. These reactions are always reversible with the metabolite indicated as a substrate with a stoichiometric coefficient of one and no products produced by the reaction. This particular convention is adopted to allow the reaction to take on a positive flux value (activity level) when the metabolite is being produced or removed from the reaction network and a negative flux value when the metabolite is being consumed or introduced into the reaction network. These reactions will be further constrained during the course of a simulation to specify exactly which metabolites are available to the cell and which can be excreted by the cell.
  • A demand exchange reaction is always specified as an irreversible reaction containing at least one substrate. These reactions are typically formulated to represent the production of an intracellular metabolite by the metabolic network or the aggregate production of many reactants in balanced ratios such as in the representation of a reaction that leads to biomass formation, also referred to as growth.
  • A demand exchange reactions can be introduced for any metabolite in a model of the invention. Most commonly these reactions are introduced for metabolites that are required to be produced by the cell for the purposes of creating a new cell such as amino acids, nucleotides, phospholipids, and other biomass constituents, or metabolites that are to be produced for alternative purposes. Once these metabolites are identified, a demand exchange reaction that is irreversible and specifies the metabolite as a substrate with a stoichiometric coefficient of unity can be created. With these specifications, if the reaction is active it leads to the net production of the metabolite by the system meeting potential production demands. Examples of processes that can be represented as a demand exchange reaction in a reaction network data structure and analyzed by the methods of the invention include, for example, production or secretion of an individual protein; production or secretion of an individual metabolite such as an amino acid, vitamin, nucleoside, antibiotic or surfactant; production of ATP for extraneous energy requiring processes such as locomotion or muscle contraction; or formation of biomass constituents.
  • In addition to these demand exchange reactions that are placed on individual metabolites, demand exchange reactions that utilize multiple metabolites in defined stoichiometric ratios can be introduced. These reactions are referred to as aggregate demand exchange reactions. An example of an aggregate demand reaction is a reaction used to simulate the concurrent growth demands or production requirements associated with cell growth that are placed on a cell, for example, by simulating the formation of multiple biomass constituents simultaneously at a particular cellular or organismic growth rate.
  • A specific reaction network is provided in FIG. 1 to exemplify the above-described reactions and their interactions. The reactions can be represented in the exemplary data structure shown in FIG. 3 as set forth below. The reaction network, shown in FIG. 1, includes intra-system reactions that occur entirely within the compartment indicated by the shaded oval such as reversible reaction R2 which acts on reactants B and G and reaction R3 which converts one equivalent of B to 2 equivalents of F. The reaction network shown in FIG. 1 also contains exchange reactions such as input/output exchange reactions Axt and Ext, and the demand exchange reaction, Vgrowth, which represents growth in response to the one equivalent of D and one equivalent of F. Other intra-system reactions include R1 which is a translocation and transformation reaction that translocates reactant A into the compartment and transforms it to reactant G and reaction R6 which is a transport reaction that translocates reactant E out of the compartment.
  • A reaction network can be represented as a set of linear algebraic equations which can be presented as a stoichiometric matrix S, with S being an m×n matrix where m corresponds to the number of reactants or metabolites and n corresponds to the number of reactions taking place in the network. An example of a stoichiometric matrix representing the reaction network of FIG. 1 is shown in FIG. 3. As shown in FIG. 3, each column in the matrix corresponds to a particular reaction n, each row corresponds to a particular reactant m, and each Smn element corresponds to the stoichiometric coefficient of the reactant m in the reaction denoted n. The stoichiometric matrix includes intra-system reactions such as R2 and R3 which are related to reactants that participate in the respective reactions according to a stoichiometric coefficient having a sign indicative of whether the reactant is a substrate or product of the reaction and a value correlated with the number of equivalents of the reactant consumed or produced by the reaction. Exchange reactions such as −Ext and −Axt are similarly correlated with a stoichiometric coefficient. As exemplified by reactant E, the same compound can be treated separately as an internal reactant (E) and an external reactant (Eexternal) such that an exchange reaction (R6) exporting the compound is correlated by stoichiometric coefficients of −1 and 1, respectively. However, because the compound is treated as a separate reactant by virtue of its compartmental location, a reaction, such as R5, which produces the internal reactant (E) but does not act on the external reactant (Eexternal) is correlated by stoichiometric coefficients of 1 and 0, respectively. Demand reactions such as Vgrowth can also be included in the stoichiometric matrix being correlated with substrates by an appropriate stoichiometric coefficient.
  • As set forth in further detail below, a stoichiometric matrix provides a convenient format for representing and analyzing a reaction network because it can be readily manipulated and used to compute network properties, for example, by using linear programming or general convex analysis. A reaction network data structure can take on a variety of formats so long as it is capable of relating reactants and reactions in the manner exemplified above for a stoichiometric matrix and in a manner that can be manipulated to determine an activity of one or more reactions using methods such as those exemplified below. Other examples of reaction network data structures that are useful in the invention include a connected graph, list of chemical reactions or a table of reaction equations.
  • A reaction network data structure can be constructed to include all reactions that are involved in metabolism occurring during the interaction of two or more cells, Homo sapiens cell metabolism or any portion thereof. A portion of an organisms metabolic reactions that can be included in a reaction network data structure of the invention includes, for example, a central metabolic pathway such as glycolysis, the TCA cycle, the PPP or ETS; or a peripheral metabolic pathway such as amino acid biosynthesis, amino acid degradation, purine biosynthesis, pyrimidine biosynthesis, lipid biosynthesis, fatty acid metabolism, vitamin or cofactor biosynthesis, transport processes and alternative carbon source catabolism. Examples of individual pathways within the peripheral pathways are set forth in Table 1. Other examples of portions of metabolic reactions that can be included in a reaction network data structure of the invention include, for example, TAG biosynthesis, muscle contraction requirements, bicarbonate buffer system and/or ammonia buffer system. Specific examples of these and other reactions are described further below and in the Examples.
  • Depending upon a particular application, a reaction network data structure can include a plurality of Homo sapiens reactions including any or all of the reactions listed in Table 1. Similarly, a reaction network data structure also can include the reactions set forth in Examples I-IV and include, for example, single reaction networks, multiple reaction networks that interact within a cell as well as multiple reaction networks that interact between cells or physiological systems.
  • For some applications, it can be advantageous to use a reaction network data structure that includes a minimal number of reactions to achieve a particular Homo sapiens activity or activity of a multicellular interaction under a particular set of environmental conditions. A reaction network data structure having a minimal number of reactions can be identified by performing the simulation methods described below in an iterative fashion where different reactions or sets of reactions are systematically removed and the effects observed. Accordingly, the invention provides a computer readable medium, containing a data structure relating a plurality of Homo sapiens reactants to a plurality of Homo sapiens reactions, wherein the plurality of Homo sapiens reactions contains at least 65 reactions. For example, the core metabolic reaction database shown in Tables 2 and 3 contains 65 reactions, and is sufficient to simulate aerobic and anaerobic metabolism on a number of carbon sources, including glucose. Similarly, the invention provides a computer readable medium containing a data structure relating a plurality of reactants of multicellular interactions to a plurality of reactions from multicellular interactions, wherein the reactions contain at least 430 for a two cell interaction. Such reactions between multicellular interactions are exemplified in Table 11, for example.
  • Depending upon the particular cell type or types, the physiological, pathological or therapeutic conditions being tested, the desired activity and the number of cellular interactions of a model or method of the invention, a reaction network data structure can contain smaller numbers of reactions such as at least 200, 150, 100 or 50 reactions. A reaction network data structure having relatively few reactions can provide the advantage of reducing computation time and resources required to perform a simulation. When desired, a reaction network data structure having a particular subset of reactions can be made or used in which reactions that are not relevant to the particular simulation are omitted. Alternatively, larger numbers of reactions can be included in order to increase the accuracy or molecular detail of the methods of the invention or to suit a particular application. Thus, a reaction network data structure can contain at least 300, 350, 400, 450, 500, 550, 600 or more reactions up to the number of reactions that occur in or by multicellular interactions, including Homo sapiens, or that are desired to simulate the activity of the full set of reactions occurring in multicellular interactions, including Homo sapiens. A reaction network data structure that is substantially complete with respect to the metabolic reactions of a multicellular organism, including Homo sapiens, provides an advantage of being relevant to a wide range of conditions to be simulated, whereas those with smaller numbers of metabolic reactions are specific to a particular subset of conditions to be simulated.
  • A Homo sapiens reaction network data structure can include one or more reactions that occur in or by Homo sapiens and that do not occur, either naturally or following manipulation, in or by another organism, such as Saccharomyces cerevisiae. It is understood that a Homo sapiens reaction network data structure of a particular cell type can also include one or more reactions that occur in another cell type. Addition of such heterologous reactions to a reaction network data structure of the invention can be used in methods to predict the consequences of heterologous gene transfer and protein expression, for example, when designing in vivo and ex vivo gene therapy approaches. Similarly, reaction networks for a multicellular interactions also can include one or more reactions that occur entirely within the species of origin of the cellular interactions or can contain one or more heterologous reactions from one or more different species.
  • The reactions included in a reaction network data structure of the invention can be metabolic reactions. A reaction network data structure can also be constructed to include other types of reactions such as regulatory reactions, signal transduction reactions, cell cycle reactions, reactions controlling developmental processes, reactions involved in apoptosis, reactions involved in responses to hypoxia, reactions involved in responses to cell-cell or cell-substrate interactions, reactions involved in protein synthesis and regulation thereof, reactions involved in gene transcription and translation, and regulation thereof, and reactions involved in assembly of a cell and its subcellular components.
  • A reaction network data structure or index of reactions used in the data structure such as that available in a metabolic reaction database, as described above, can be annotated to include information about a particular reaction. A reaction can be annotated to indicate, for example, assignment of the reaction to a protein, macromolecule or enzyme that performs the reaction, assignment of a gene(s) that codes for the protein, macromolecule or enzyme, the Enzyme Commission (EC) number of the particular metabolic reaction, a subset of reactions to which the reaction belongs, citations to references from which information was obtained, or a level of confidence with which a reaction is believed to occur in Homo sapiens or other organism. A computer readable medium or media of the invention can include a gene database containing annotated reactions. Such information can be obtained during the course of building a metabolic reaction database or model of the invention as described below.
  • As used herein, the term “gene database” is intended to mean a computer readable medium or media that contains at least one reaction that is annotated to assign a reaction to one or more macromolecules that perform the reaction or to assign one or more nucleic acid that encodes the one or more macromolecules that perform the reaction. A gene database can contain a plurality of reactions, some or all of which are annotated. An annotation can include, for example, a name for a macromolecule; assignment of a function to a macromolecule; assignment of an organism that contains the macromolecule or produces the macromolecule; assignment of a subcellular location for the macromolecule; assignment of conditions under which a macromolecule is regulated with respect to performing a reaction, being expressed or being degraded; assignment of a cellular component that regulates a macromolecule; an amino acid or nucleotide sequence for the macromolecule; a mRNA isoform, enzyme isoform, or any other desirable annotation or annotation found for a macromolecule in a genome database such as those that can be found in Genbank, a site maintained by the NCBI (ncbi.nlm.gov), the Kyoto Encyclopedia of Genes and Genomes (KEGG) (www.genome.ad.jp/kegg/), the protein database SWISS-PROT (ca.expasy.org/sprot/), the LocusLink database maintained by the NCBI (www.ncbi.nlm.nih.gov/LocusLink/), the Enzyme Nomenclature database maintained by G.P. Moss of Queen Mary and Westfield College in the United Kingdom (www.chem.qmw.ac.uk/iubmb/enzyme/).
  • A gene database of the invention can include a substantially complete collection of genes or open reading frames in a multicellular organism, including Homo sapiens, or a substantially complete collection of the macromolecules encoded by the organism's genome. Alternatively, a gene database can include a portion of genes or open reading frames in an organism or a portion of the macromolecules encoded by the organism's genome, such as the portion that includes substantially all metabolic genes or macromolecules. The portion can be at least 10%, 15%, 20%, 25%, 50%, 75%, 90% or 95% of the genes or open reading frames encoded by the organism's genome, or the macromolecules encoded therein. A gene database can also include macromolecules encoded by at least a portion of the nucleotide sequence for the organism's genome such as at least 10%, 15%, 20%, 25%, 50%, 75%, 90% or 95% of the organism's genome. Accordingly, a computer readable medium or media of the invention can include at least one reaction for each macromolecule encoded by a portion of an organism's genome, including a Homo sapiens genome.
  • An in silico model of multicellular interactions, including a Homo sapiens model, of the invention can be built by an iterative process which includes gathering information regarding particular reactions to be added to a model, representing the reactions in a reaction network data structure, and performing preliminary simulations wherein a set of constraints is placed on the reaction network and the output evaluated to identify errors in the network. Errors in the network such as gaps that lead to non-natural accumulation or consumption of a particular metabolite can be identified as described below and simulations repeated until a desired performance of the model is attained. An exemplary method for iterative model construction is provided in Example I. For multicellular interactions, an iterative process includes producing one or more component reaction networks followed by combining the components into a higher order multi-network system, as described in Example IV. For example, components can include the central metabolism reaction network and the cell specific reaction networks such as TAG biosynthesis for adipocytes or muscle contraction for myocytes. Combination of the central metabolism and the cell specific reaction networks into a single model produces, for example, a cell specific reaction network. Components also can include the individual cell types, tissues, physiological systems or intra-system reaction networks that are constituents of the larger multicellular system. Combining these components into a larger model produces, for example, a model describing the relationships and interactions of the multicellular system together with its various interactions.
  • Thus, the invention provides a method for making a data structure relating a plurality of reactants to a plurality of reactions in a computer readable medium or media. The method includes the steps of: (a) identifying a plurality of reactions and a plurality of reactants that are substrates and products of the reactions; (b) relating the plurality of reactants to the plurality of Homo sapiens reactions in a data structure, wherein each of the reactions includes a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating the substrate and the product; (c) making a constraint set for the plurality of reactions; (d) providing an objective function; (e) determining at least one flux distribution that minimizes or maximizes the objective function when the constraint set is applied to the data structure, and (f) if the at least one flux distribution is not predictive of physiology, then adding a reaction to or deleting a reaction from the data structure and repeating step (e), if the at least one flux distribution is predictive of physiology, then storing the data structure in a computer readable medium or media. The method can be applied to multicellular interactions within or among single or multicellular organisms, including Homo sapiens.
  • Information to be included in a data structure of the invention can be gathered from a variety of sources including, for example, annotated genome sequence information and biochemical literature.
  • Sources of annotated human genome sequence information include, for example, KEGG, SWISS-PROT, LocusLink, the Enzyme Nomenclature database, the International Human Genome Sequencing Consortium and commercial databases. KEGG contains a broad range of information, including a substantial amount of metabolic reconstruction. The genomes of 304 organisms can be accessed here, with gene products grouped by coordinated functions, often represented by a map (e.g., the enzymes involved in glycolysis would be grouped together). The maps are biochemical pathway templates which show enzymes connecting metabolites for various parts of metabolism. These general pathway templates are customized for a given organism by highlighting enzymes on a given template which have been identified in the genome of the organism. Enzymes and metabolites are active and yield useful information about stoichiometry, structure, alternative names and the like, when accessed.
  • SWISS-PROT contains detailed information about protein function. Accessible information includes alternate gene and gene product names, function, structure and sequence information, relevant literature references, and the like.
  • LocusLink contains general information about the locus where the gene is located and, of relevance, tissue specificity, cellular location, and implication of the gene product in various disease states.
  • The Enzyme Nomenclature database can be used to compare the gene products of two organisms. Often the gene names for genes with similar functions in two or more organisms are unrelated. When this is the case, the E.C. (Enzyme Commission) numbers can be used as unambiguous indicators of gene product function. The information in the Enzyme Nomenclature database is also published in Enzyme Nomenclature (Academic Press, San Diego, Calif., 1992) with 5 supplements to date, all found in the European Journal of Biochemistry (Blackwell Science, Malden, Mass.).
  • Sources of biochemical information include, for example, general resources relating to metabolism, resources relating specifically to human metabolism, and resources relating to the biochemistry, physiology and pathology of specific human cell types.
  • Sources of general information relating to metabolism, which were used to generate the human reaction databases and models described herein, were J. G. Salway, Metabolism at a Glance, 2nd ed., Blackwell Science, Malden, Mass. (1999) and T. M. Devlin, ed., Textbook of Biochemistry with Clinical Correlations, 4th ed., John Wiley and Sons, New York, N.Y. (1997). Human metabolism-specific resources included J. R. Bronk, Human Metabolism: Functional Diversity and Integration, Addison Wesley Longman, Essex, England (1999).
  • The literature used in conjunction with the skeletal muscle metabolic models and simulations described herein included R. Maughan et al., Biochemistry of Exercise and Training, Oxford University Press, Oxford, England (1997), as well as references on muscle pathology such as S. Carpenter et al., Pathology of Skeletal Muscle, 2nd ed., Oxford University Press, Oxford, England (2001), and more specific articles on muscle metabolism as may be found in the Journal of Physiology (Cambridge University Press, Cambridge, England).
  • In the course of developing an in silico model of metabolism during or for multicellular interactions, the types of data that can be considered include, for example, biochemical information which is information related to the experimental characterization of a chemical reaction, often directly indicating a protein(s) associated with a reaction and the stoichiometry of the reaction or indirectly demonstrating the existence of a reaction occurring within a cellular extract; genetic information, which is information related to the experimental identification and genetic characterization of a gene(s) shown to code for a particular protein(s) implicated in carrying out a biochemical event; genomic information, which is information related to the identification of an open reading frame and functional assignment, through computational sequence analysis, that is then linked to a protein performing a biochemical event; physiological information, which is information related to overall cellular physiology, fitness characteristics, substrate utilization, and phenotyping results, which provide evidence of the assimilation or dissimilation of a compound used to infer the presence of specific biochemical event (in particular translocations); and modeling information, which is information generated through the course of simulating activity of cells, tissues or physiological systems using methods such as those described herein which lead to predictions regarding the status of a reaction such as whether or not the reaction is required to fulfill certain demands placed on a metabolic network. Additional information relevant to multicellular organisms that can be considered includes, for example, cell type-specific or condition-specific gene expression information, which can be determined experimentally, such as by gene array analysis or from expressed sequence tag (EST) analysis, or obtained from the biochemical and physiological literature.
  • The majority of the reactions occurring in a multicellular organism's reaction networks are catalyzed by enzymes/proteins, which are created through the transcription and translation of the genes found within the chromosome in the cell. The remaining reactions occur either spontaneously or through non-enzymatic processes. Furthermore, a reaction network data structure can contain reactions that add or delete steps to or from a particular reaction pathway. For example, reactions can be added to optimize or improve performance of a model for multicellular interactions in view of empirically observed activity. Alternatively, reactions can be deleted to remove intermediate steps in a pathway when the intermediate steps are not necessary to model flux through the pathway. For example, if a pathway contains 3 nonbranched steps, the reactions can be combined or added together to give a net reaction, thereby reducing memory required to store the reaction network data structure and the computational resources required for manipulation of the data structure.
  • The reactions that occur due to the activity of gene-encoded enzymes can be obtained from a genome database which lists genes identified from genome sequencing and subsequent genome annotation. Genome annotation consists of the locations of open reading frames and assignment of function from homology to other known genes or empirically determined activity. Such a genome database can be acquired through public or private databases containing annotated nucleic acid or protein sequences, including Homo sapiens sequences. If desired, a model developer can perform a network reconstruction and establish the model content associations between the genes, proteins, and reactions as described, for example, in Covert et al. Trends in Biochemical Sciences 26:179-186 (2001) and Palsson, WO 00/46405.
  • As reactions are added to a reaction network data structure or metabolic reaction database, those having known or putative associations to the proteins/enzymes which enable/catalyze the reaction and the associated genes that code for these proteins can be identified by annotation. Accordingly, the appropriate associations for all of the reactions to their related proteins or genes or both can be assigned. These associations can be used to capture the non-linear relationship between the genes and proteins as well as between proteins and reactions. In some cases one gene codes for one protein which then perform one reaction. However, often there are multiple genes which are required to create an active enzyme complex and often there are multiple reactions that can be carried out by one protein or multiple proteins that can carry out the same reaction. These associations capture the logic (i.e. AND or OR relationships) within the associations. Annotating a metabolic reaction database with these associations can allow the methods to be used to determine the effects of adding or eliminating a particular reaction not only at the reaction level, but at the genetic or protein level in the context of running a simulation or predicting a multicellular interaction activity, including Homo sapiens activity.
  • A reaction network data structure of the invention can be used to determine the activity of one or more reactions in a plurality of reactions occurring from multicellular interactions, including a plurality of Homo sapiens reactions, independent of any knowledge or annotation of the identity of the protein that performs the reaction or the gene encoding the protein. A model that is annotated with gene or protein identities can include reactions for which a protein or encoding gene is not assigned. While a large portion of the reactions in a cellular metabolic network are associated with genes in the organism's genome, there are also a substantial number of reactions included in a model for which there are no known genetic associations. Such reactions can be added to a reaction database based upon other information that is not necessarily related to genetics such as biochemical or cell based measurements or theoretical considerations based on observed biochemical or cellular activity. For example, there are many reactions that can either occur spontaneously or are not protein-enabled reactions. Furthermore, the occurrence of a particular reaction in a cell for which no associated proteins or genetics have been currently identified can be indicated during the course of model building by the iterative model building methods of the invention.
  • The reactions in a reaction network data structure or reaction database can be assigned to subsystems by annotation, if desired. The reactions can be subdivided according to biological criteria, such as according to traditionally identified metabolic pathways (glycolysis, amino acid metabolism and the like) or according to mathematical or computational criteria that facilitate manipulation of a model that incorporates or manipulates the reactions. Methods and criteria for subdividing a reaction database are described in further detail in Schilling et al., J. Theor. Biol. 203:249-283 (2000), and in Schuster et al., Bioinformatics 18:351-361 (2002). The use of subsystems can be advantageous for a number of analysis methods, such as extreme pathway analysis, and can make the management of model content easier. Although assigning reactions to subsystems can be achieved without affecting the use of the entire model for simulation, assigning reactions to subsystems can allow a user to search for reactions in a particular subsystem which may be useful in performing various types of analyses. Therefore, a reaction network data structure can include any number of desired subsystems including, for example, 2 or more subsystems, 5 or more subsystems, 10 or more subsystems, 25 or more subsystems or 50 or more subsystems.
  • The reactions in a reaction network data structure or metabolic reaction database can be annotated with a value indicating the confidence with which the reaction is believed to occur in one or more cells of a multicellular interaction or in one or more reaction networks within a cell such as a Homo sapiens cell. The level of confidence can be, for example, a function of the amount and form of supporting data that is available. This data can come in various forms including published literature, documented experimental results, or results of computational analyses. Furthermore, the data can provide direct or indirect evidence for the existence of a chemical reaction in a cell based on genetic, biochemical, and/or physiological data.
  • The invention further provides a computer readable medium, containing (a) a data structure relating a plurality of Homo sapiens reactants to a plurality of Homo sapiens reactions, wherein each of the Homo sapiens reactions includes a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating the substrate and the product, and (b) a constraint set for the plurality of Homo sapiens reactions. Similarly, the computer readable medium or media can relate a plurality of reactions to a plurality of reactions within first and second cells and for an intra-system between first and second interacting cells.
  • Constraints can be placed on the value of any of the fluxes in the metabolic network using a constraint set. These constraints can be representative of a minimum or maximum allowable flux through a given reaction, possibly resulting from a limited amount of an enzyme present. Additionally, the constraints can determine the direction or reversibility of any of the reactions or transport fluxes in the reaction network data structure. Based on the in vivo environment where multiple cells interact, such as in a human organism, the metabolic resources available to the cell for biosynthesis of essential molecules for can be determined. Allowing the corresponding transport fluxes to be active provides the in silico interaction between cells with inputs and outputs for substrates and by-products produced by the metabolic network.
  • Returning to the hypothetical reaction network shown in FIG. 1, constraints can be placed on each reaction in the exemplary format shown in FIG. 2, as follows. The constraints are provided in a format that can be used to constrain the reactions of the stoichiometric matrix shown in FIG. 3. The format for the constraints used for a matrix or in linear programming can be conveniently represented as a linear inequality such as

  • bj≦vj≦aj:j=1 . . . n  (Eq. 1)
  • where vj is the metabolic flux vector, bj is the minimum flux value and aj is the maximum flux value. Thus, aj can take on a finite value representing a maximum allowable flux through a given reaction or bj can take on a finite value representing minimum allowable flux through a given reaction. Additionally, if one chooses to leave certain reversible reactions or transport fluxes to operate in a forward and reverse manner the flux may remain unconstrained by setting bj to negative infinity and aj to positive infinity as shown for reaction R2 in FIG. 2. If reactions proceed only in the forward reaction bj is set to zero while aj is set to positive infinity as shown for reactions R1, R3, R4, R5, and R6 in FIG. 2. As an example, to simulate the event of a genetic deletion or non-expression of a particular protein, the flux through all of the corresponding metabolic reactions related to the gene or protein in question are reduced to zero by setting aj and bj to be zero. Furthermore, if one wishes to simulate the absence of a particular growth substrate one can simply constrain the corresponding transport fluxes that allow the metabolite to enter the cell to be zero by setting aj and bj to be zero. On the other hand if a substrate is only allowed to enter or exit the cell via transport mechanisms, the corresponding fluxes can be properly constrained to reflect this scenario.
  • The ability of a reaction to be actively occurring is dependent on a large number of additional factors beyond just the availability of substrates. These factors, which can be represented as variable constraints in the models and methods of the invention include, for example, the presence of cofactors necessary to stabilize the protein/enzyme, the presence or absence of enzymatic inhibition and activation factors, the active formation of the protein/enzyme through translation of the corresponding mRNA transcript, the transcription of the associated gene(s) or the presence of chemical signals and/or proteins that assist in controlling these processes that ultimately determine whether a chemical reaction is capable of being carried out within an organism. Of particular importance in the regulation of human cell types is the implementation of paracrine and endocrine signaling pathways to control cellular activities. In these cases a cell secretes signaling molecules that may be carried far afield to act on distant targets (endocrine signaling), or act as local mediators (paracrine signaling). Examples of endocrine signaling molecules include hormones such as insulin, while examples of paracrine signaling molecules include neurotransmitters such as acetylcholine. These molecules induce cellular responses through signaling cascades that affect the activity of biochemical reactions in the cell. Regulation can be represented in an in silico Homo sapiens model by providing a variable constraint as set forth below.
  • Thus, the invention provides a computer readable medium or media, including (a) a data structure relating a plurality of Homo sapiens reactants to a plurality of Homo sapiens reactions, wherein each of the reactions includes a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating the substrate and the product, and wherein at least one of the reactions is a regulated reaction; and (b) a constraint set for the plurality of reactions, wherein the constraint set includes a variable constraint for the regulated reaction. Additionally, the invention provides a computer readable medium or media including data structures for two or more cells and for an intra-system and a constraint set for the plurality of reactions within the data structures that includes a variable constraint for a regulated reaction.
  • As used herein, the term “regulated,” when used in reference to a reaction in a data structure, is intended to mean a reaction that experiences an altered flux due to a change in the value of a constraint or a reaction that has a variable constraint.
  • As used herein, the term “regulatory reaction” is intended to mean a chemical conversion or interaction that alters the activity of a protein, macromolecule or enzyme. A chemical conversion or interaction can directly alter the activity of a protein, macromolecule or enzyme such as occurs when the protein, macromolecule or enzyme is post-translationally modified or can indirectly alter the activity of a protein, macromolecule or enzyme such as occurs when a chemical conversion or binding event leads to altered expression of the protein, macromolecule or enzyme. Thus, transcriptional or translational regulatory pathways can indirectly alter a protein, macromolecule or enzyme or an associated reaction. Similarly, indirect regulatory reactions can include reactions that occur due to downstream components or participants in a regulatory reaction network. When used in reference to a data structure or in silico Homo sapiens model, for example, the term is intended to mean a first reaction that is related to a second reaction by a function that alters the flux through the second reaction by changing the value of a constraint on the second reaction.
  • As used herein, the term “regulatory data structure” is intended to mean a representation of an event, reaction or network of reactions that activate or inhibit a reaction, the representation being in a format that can be manipulated or analyzed. An event that activates a reaction can be an event that initiates the reaction or an event that increases the rate or level of activity for the reaction. An event that inhibits a reaction can be an event that stops the reaction or an event that decreases the rate or level of activity for the reaction. Reactions that can be represented in a regulatory data structure include, for example, reactions that control expression of a macromolecule that in turn, performs a reaction such as transcription and translation reactions, reactions that lead to post translational modification of a protein or enzyme such as phosphorylation, dephosphorylation, prenylation, methylation, oxidation or covalent modification, reactions that process a protein or enzyme such as removal of a pre- or pro-sequence, reactions that degrade a protein or enzyme or reactions that lead to assembly of a protein or enzyme.
  • As used herein, the term “regulatory event” is intended to mean a modifier of the flux through a reaction that is independent of the amount of reactants available to the reaction. A modification included in the term can be a change in the presence, absence, or amount of an enzyme that performs a reaction. A modifier included in the term can be a regulatory reaction such as a signal transduction reaction or an environmental condition such as a change in pH, temperature, redox potential or time. It will be understood that when used in reference to an in silico Homo sapiens model or data structure, or when used in reference to a model or data structure for a multicellular interaction, a regulatory event is intended to be a representation of a modifier of the flux through a Homo sapiens reaction or reaction occurring in one or more cells in a multicellular interaction that is independent of the amount of reactants available to the reaction.
  • The effects of regulation on one or more reactions that occur in Homo sapiens can be predicted using an in silico Homo sapiens model or multicellular model of the invention. Regulation can be taken into consideration in the context of a particular condition being examined by providing a variable constraint for the reaction in an in silico Homo sapiens model or multicellular model. Such constraints constitute condition-dependent constraints. A data structure can represent regulatory reactions as Boolean logic statements (Reg-reaction). The variable takes on a value of 1 when the reaction is available for use in the reaction network and will take on a value of 0 if the reaction is restrained due to some regulatory feature. A series of Boolean statements can then be introduced to mathematically represent the regulatory network as described for example in Covert et al. J. Theor. Biol. 213:73-88 (2001). For example, in the case of a transport reaction (A_in) that imports metabolite A, where metabolite A inhibits reaction R2 as shown in FIG. 4, a Boolean rule can state that:

  • Reg−R2=IF NOT(A_in).  (Eq. 2)
  • This statement indicates that reaction R2 can occur if reaction A_in is not occurring (i.e. if metabolite A is not present). Similarly, it is possible to assign the regulation to a variable A which would indicate an amount of A above or below a threshold that leads to the inhibition of reaction R2. Any function that provides values for variables corresponding to each of the reactions in the biochemical reaction network can be used to represent a regulatory reaction or set of regulatory reactions in a regulatory data structure. Such functions can include, for example, fuzzy logic, heuristic rule-based descriptions, differential equations or kinetic equations detailing system dynamics.
  • A reaction constraint placed on a reaction can be incorporated into an in silico Homo sapiens model or multicellular model of interacting cells using the following general equation:

  • (Reg−Reaction)*b j ≦v j ≦a j*(Reg−Reaction),∀

  • j=1 . . . n  (Eq. 3)
  • For the example of reaction R2 this equation is written as follows:

  • (0)*Reg−R2≦R2≦(∞)*Reg−R2.  (Eq. 4)
  • Thus, during the course of a simulation, depending upon the presence or absence of metabolite A in the interior of the cell where reaction R2 occurs, the value for the upper boundary of flux for reaction R2 will change from 0 to infinity, respectively.
  • With the effects of a regulatory event or network taken into consideration by a constraint function and the condition-dependent constraints set to an initial relevant value, the behavior of the Homo sapiens reaction network or one or more reaction networks of a multicellular interaction can be simulated for the conditions considered as set forth below.
  • Although regulation has been exemplified above for the case where a variable constraint is dependent upon the outcome of a reaction in the data structure, a plurality of variable constraints can be included in an in silico Homo sapiens model or other model of multicellular interactions to represent regulation of a plurality of reactions. Furthermore, in the exemplary case set forth above, the regulatory structure includes a general control stating that a reaction is inhibited by a particular environmental condition. Using a general control of this type, it is possible to incorporate molecular mechanisms and additional detail into the regulatory structure that is responsible for determining the active nature of a particular chemical reaction within an organism.
  • Regulation can also be simulated by a model of the invention and used to predict a Homo sapiens physiological function without knowledge of the precise molecular mechanisms involved in the reaction network being modeled. Thus, the model can be used to predict, in silico, overall regulatory events or causal relationships that are not apparent from in vivo observation of any one reaction in a network or whose in vivo effects on a particular reaction are not known. Such overall regulatory effects can include those that result from overall environmental conditions such as changes in pH, temperature, redox potential, or the passage of time.
  • As described previously and further below, the models and method of the invention are applicable to a wide range of multicellular interactions. The multicellular interactions include, for example, interactions between prokaryotic cells such as colony growth and chemotaxis. The multicellular interactions include, for example, interactions between two or more eukaryotic cells such as the concerted action of two or more cells of the same or different cell type. A specific example of the concerted action of the same cell type includes the combined output of the contractile activity of myocytes. A specific example of the concerted action of different cell types includes the energy production of adipocyte cells and the contractile activity of myocyte cells based on the consumption of energy available from the adipocyte cells. Multicellular interactions also can include, for example, interactions between host cells and a pathogen, such as a bacteria, virus or worm, as well as symbiotic interactions between host cells and microbes, for example. A symbiotic microbe can include, for example, E. coli. Further examples of host and microbe interactions include bacterial communities that reside in the skin and mouth and the vagina flora, providing the host with a defense against infections. Moreover, the models and methods of the invention also can be used to reconstruction the reaction networks between a plurality of dynamic multicellular interactions including, for example, interactions between host cells or tissues, pathogen and symbiotic microbe.
  • Multicellular interactions also include, for example, interactions between cells of different tissues, different organs and/or physiological systems as well as interactions between some or all cells, tissues organs and/or physiological systems within a multicellular organism. Specific examples of such interactions include organismic homeostasis, signal transduction, the endocrine system, the exocrine system, sensory transduction, secretion, the hematopoietic system, the immune system, cell migration, cell adherence, cell invasion and neuronal and synaptic transduction. Numerous other multicellular interactions are well known in the art and can similarly be reconstructed and simulated to predict an activity thereof using the models and methods of the invention.
  • Given the teachings and guidance provided herein with respect to the construction and use of multiple reaction networks including, for example, the regulated and metabolic reaction networks of a Homo sapiens cell, those skilled in the art will know how to employ the models and methods of the invention for the construction and use of any multicellular interaction. Specific examples of such multicellular interactions are described above. Other examples of multicellular interactions include, for example, all interactions occurring between two or more cells such as those cells set forth in Table 5 below. Such multicellular interactions can occur between cells within the same or different physiological category or functional characterization. Similarly, such multicellular interactions also can occur between cells within the same and between different physiological categories or functional characterizations. The number and types of different cellular interactions will be determined by the multicellular model being produced using the methods of the invention.
  • Models of multicellular interactions also can include, for example, interactions between cells of one or more tissues and organs. The models and methods of the invention are applicable to predict the activity of interactions between some or all cell types of a tissue or organ. The models and methods of the invention also can include reaction networks that include interactions between some or all cell types of two or more tissues or organs. Specific examples of tissues or organs and their respective cell types and functions are shown below in Table 6. The models and methods of the invention can include, for example, some or all of these interactions to predict their respective activities. Similarly, Table 7 exemplifies the cell types of a liver. Given the teachings and guidance provided herein, the models and methods of the invention can be used to construct an in silico reconstruction of the reaction networks for some or all of these cell types to predict some or all of the activities of the liver. Further, an in silico reconstruction of reaction networks for some or all multicellular interactions exemplified in Tables 5-7, including those within and between tissues and organs, can be produced that can be used to predict some or all activities of one or more tissues or of an organism. Therefore, the invention provides for the in silico reconstruction of whole organisms, including human organisms, tissues, cells and physical or physiological functions performed by such cellular systems.
  • The invention also provides for the in silico reconstruction of a plurality of reaction networks that interact to perform the same or different activity. The plurality can be a small, medium or large plurality and can reside within the same cell, different cells or in different tissues or organisms. Specific examples of such pluralities residing within the same cell include the reaction networks exemplified below in Example IV for a myocyte or for an adipocyte. Specific examples of such pluralities residing in different cells or tissues include the reaction networks exemplified below in Example IV for coupled adipocyte-myocyte metabolism. Another example of interactions between different reaction networks within different networks includes interactions between pathogen and host cells.
  • Briefly, and as described previously, a computer readable medium or media can be produced that includes a plurality of data structures each relating a plurality of reactants to a plurality of reactions from each cell within the multicellular interaction. The reactions include a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating the substrate and said product In a two cell interaction, including populations of two cell types, the plurality of data structures can include a first data structure and a second data structure corresponding to the reactions within the two cells or populations of two cell types. The data structures will describe the reaction networks for each cell.
  • For optimization of the multicellular interaction containing two cells, a third data structure is particularly useful for relating a plurality of intra-system reactants to a plurality of intra-system reactions between the first and second cells. Each of the intra-system reactions includes a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating the substrate and said product. The intra-system data structure can be included in the reconstruction as an independent data structure or as a component of one or more data structures for either or both cells within such a two cell interaction model. A specific example of intra-system reactions represented by a third data structure is shown in FIGS. 10-1 through 10-70 for the bicarbonate and ammonia buffer systems employed in the two cell model describing adipocyte and myocyte interactions.
  • As with the models and methods of the invention described above and below, a computer readable medium or media describing a multicellular interaction also will contain a constraint set for the plurality of reactions for each of the first, second and third data structures as well as commands for determining at least one flux distribution that minimizes or maximizes an objective function when said constraint set is applied to said first and second data structures. The objective function can be, for example, those objective functions exemplified previously, those exemplified below or in the Examples as well as various other object functions well known to those skilled in the art given the teachings and guidance provided herein. Solving the optimization problem by determining one or more flux distribution will predict a physiological function of occurring as a result of the interaction between the first and second cells of the model.
  • Each of the first, second or third data structures can include one or more reaction networks. For example, and with reference to FIGS. 5-1 through 5-9, 6, 7-1 through 7-35, 8, 9-1 through 9-35, and 10-1 through 10-70, a reaction network for each of the cells exemplified therein can be defined as the different networks within each cell such as central metabolism and the cell specific reactions. Applying this view, the adipocyte and myocyte cells each contain at least two reaction networks. When combined together with the intra-cellular reaction network and the exchange reactions, the interactions of the two cells exemplified in FIG. 6 can be described by at least five different reaction networks. The interactions of this two cell model can therefore be described using at least five data structures. Alternatively, a reaction network can be defined as all the networks within each cell. When combined together with the intra-cellular reaction network and the exchange reactions, the interactions of the exemplified adipocyte and myocyte cells can be described by at least three different reaction networks. One reaction network for each cell and one reaction network for the intra-system reactions. Therefore, each of the first, second or third data structures can consist of a plurality of two or more reaction networks including, for example, 2, 3, 4, 5, 10, 20 or 25 or more as well as all integer numbers between and above these exemplary numbers. Similarly, given the teachings and guidance provided herein, the models and methods of the invention can be generated and used to predict an activity and/or physiological function of the intercellular network interactions or the intracellular network interaction. The latter interactions, for example, also predict an activity and/or a physiological function of the interactions between two or more cells including cells of different tissues, organs of a multicellular organism or of a whole organism.
  • As with the number of reaction networks within a data structure, the models and methods of the invention also can employ greater than three data structures as exemplified above. For example, the models and method of the invention can comprise one or more fourth data structures having one or more fourth constraint sets where each fourth data structure relates a plurality of reactants to a plurality of reactions from a cell already included in the model or from one or more third cells within the multicellular interaction. Use of one or more fourth data structures is particularly useful when reconstructing a interactions between three or more interacting cells including a large plurality of cells such as the cells within a tissue, organ, physiological system or organism. Each of the reactions within such fourth data structures include a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating the substrate and said product.
  • The number of fourth data structures can correspond to the number of cells greater than the first and second cells of the multicellular interaction and include, for example, a plurality of data structures. As with the specific embodiment of a two cell interaction, the plurality of data structures for three or more interacting cells can correspond to different cells within the cellular interaction as well as correspond to different cell types within the cellular interaction. The number of cells can include, for example, at least 4 cells, 5 cells, 6 cells, 7 cells, 8 cells, 9 cells, 10 cells, 100 cells, 1000 cells, 5000 cells, 10,000 cells or more. Therefore, the number of cells within a multicellular interaction model or used in a method of predicting a behavior of such multicellular interactions can include some or all cells which constitute a group of interacting cells, a tissue, organ, physiological system or whole organism. The multicellular interaction models and methods of the invention also can include some or all cells which constitute a group of interacting cells of different types or from different tissues, organs, physiological systems or organisms. The organism can be single cell prokaryotic or eukaryotic organism or multicellular eukaryotic organisms. Specific examples of different cell types include a mammary gland cell, hepatocyte, white fat cell, brown fat cell, liver lipocyte, red skeletal muscle cell, white skeletal muscle cell, intermediate skeletal muscle cell, smooth muscle cell, red blood cell, adipocyte, monocyte, reticulocyte, fibroblast, neuronal cell epithelial cell or one or more cells set forth in Table 5. Specific examples of physiological functions resulting from multicellular interactions that can be predicted include metabolite yield, ATP yield, biomass demand, growth, triacylglycerol storage, muscle contraction, milk secretion and oxygen transport capacity.
  • Intra-system reactions of a multicellular interaction model or method of the invention has been exemplified above and below with reference to the extracellular in vivo environment and, in particular, with reference to buffering this environment by supplying functions of the renal system. Given the teachings and guidance provided herein, those skilled in the art will understand that any extracellular reaction, plurality of reactions, function of the extracellular space or function supplied into the extracellular space by another cell, tissue or physiological system can be employed as an intra-system reaction network. Such reactions or activities can represent normal or pathological conditions or both conditions occurring within this intra-system environment. Specific examples of intra-system reactions include one or more reactions performed in the hematopoietic system, urine, connective tissue, contractile tissue or cells, lymphatic system, respiratory system or renal system. Reactions or reactants included in one or more intra-system data structures can be, for example, bicarbonate buffer system, an ammonia buffer system, a hormone, a signaling molecule, a vitamin, a mineral or a combination thereof.
  • The in silico models of multicellular or multi-network interactions, including Homo sapiens model and methods, described herein can be implemented on any conventional host computer system, such as those based on Intel® microprocessors and running Microsoft Windows operating systems. Other systems, such as those using the UNIX or LINUX operating system and based on IBM®, DEC® or Motorola® microprocessors are also contemplated. The systems and methods described herein can also be implemented to run on client-server systems and wide-area networks, such as the Internet.
  • Software to implement a method or model of the invention can be written in any well-known computer language, such as Java, C, C++, Visual Basic, FORTRAN or COBOL and compiled using any well-known compatible compiler. The software of the invention normally runs from instructions stored in a memory on a host computer system. A memory or computer readable medium can be a hard disk, floppy disc, compact disc, magneto-optical disc, Random Access Memory, Read Only Memory or Flash Memory. The memory or computer readable medium used in the invention can be contained within a single computer or distributed in a network. A network can be any of a number of conventional network systems known in the art such as a local area network (LAN) or a wide area network (WAN). Client-server environments, database servers and networks that can be used in the invention are well known in the art. For example, the database server can run on an operating system such as UNIX, running a relational database management system, a World Wide Web application and a World Wide Web server. Other types of memories and computer readable media are also contemplated to function within the scope of the invention.
  • A database or data structure of the invention can be represented in a markup language format including, for example, Standard Generalized Markup Language (SGML), Hypertext markup language (HTML) or Extensible Markup language (XML). Markup languages can be used to tag the information stored in a database or data structure of the invention, thereby providing convenient annotation and transfer of data between databases and data structures. In particular, an XML format can be useful for structuring the data representation of reactions, reactants and their annotations; for exchanging database contents, for example, over a network or internet; for updating individual elements using the document object model; or for providing differential access to multiple users for different information content of a data base or data structure of the invention. XML programming methods and editors for writing XML code are known in the art as described, for example, in Ray, “Learning XML” O'Reilly and Associates, Sebastopol, Calif. (2001).
  • A set of constraints can be applied to a reaction network data structure to simulate the flux of mass through the reaction network under a particular set of environmental conditions specified by a constraints set. Because the time constants characterizing metabolic transients and/or metabolic reactions are typically very rapid, on the order of milli-seconds to seconds, compared to the time constants of cell growth on the order of hours to days, the transient mass balances can be simplified to only consider the steady state behavior. Referring now to an example where the reaction network data structure is a stoichiometric matrix, the steady state mass balances can be applied using the following system of linear equations

  • S·v=0  (Eq. 5)
  • where S is the stoichiometric matrix as defined above and v is the flux vector. This equation defines the mass, energy, and redox potential constraints placed on the metabolic network as a result of stoichiometry. Together Equations 1 and 5 representing the reaction constraints and mass balances, respectively, effectively define the capabilities and constraints of the metabolic genotype and the organism's metabolic potential. All vectors, v, that satisfy Equation 5 are said to occur in the mathematical nullspace of S. Thus, the null space defines steady-state metabolic flux distributions that do not violate the mass, energy, or redox balance constraints. Typically, the number of fluxes is greater than the number of mass balance constraints, thus a plurality of flux distributions satisfy the mass balance constraints and occupy the null space. The null space, which defines the feasible set of metabolic flux distributions, is further reduced in size by applying the reaction constraints set forth in Equation 1 leading to a defined solution space. A point in this space represents a flux distribution and hence a metabolic phenotype for the network. An optimal solution within the set of all solutions can be determined using mathematical optimization methods when provided with a stated objective and a constraint set. The calculation of any solution constitutes a simulation of the model.
  • Objectives for activity of a human cell can be chosen. While the overall objective of a multi-cellular organism may be growth or reproduction, individual human cell types generally have much more complex objectives, even to the seemingly extreme objective of apoptosis (programmed cell death), which may benefit the organism but certainly not the individual cell. For example, certain cell types may have the objective of maximizing energy production, while others have the objective of maximizing the production of a particular hormone, extracellular matrix component, or a mechanical property such as contractile force. In cases where cell reproduction is slow, such as human skeletal muscle, growth and its effects need not be taken into account. In other cases, biomass composition and growth rate could be incorporated into a “maintenance” type of flux, where rather than optimizing for growth, production of precursors is set at a level consistent with experimental knowledge and a different objective is optimized.
  • Certain cell types, including cancer cells, can be viewed as having an objective of maximizing cell growth. Growth can be defined in terms of biosynthetic requirements based on literature values of biomass composition or experimentally determined values such as those obtained as described above. Thus, biomass generation can be defined as an exchange reaction that removes intermediate metabolites in the appropriate ratios and represented as an objective function. In addition to draining intermediate metabolites this reaction flux can be formed to utilize energy molecules such as ATP, NADH and NADPH so as to incorporate any maintenance requirement that must be met. This new reaction flux then becomes another constraint/balance equation that the system must satisfy as the objective function. Using the stoichiometric matrix of FIG. 3 as an example, adding such a constraint is analogous to adding the additional column Vgrowth to the stoichiometric matrix to represent fluxes to describe the production demands placed on the metabolic system. Setting this new flux as the objective function and asking the system to maximize the value of this flux for a given set of constraints on all the other fluxes is then a method to simulate the growth of the organism.
  • Continuing with the example of the stoichiometric matrix applying a constraint set to a reaction network data structure can be illustrated as follows. The solution to equation 5 can be formulated as an optimization problem, in which the flux distribution that minimizes a particular objective is found. Mathematically, this optimization problem can be stated as:

  • Minimize Z  (Eq. 6)

  • where z=Σc i ·v i  (Eq. 7)
  • where Z is the objective which is represented as a linear combination of metabolic fluxes vi using the weights ci in this linear combination. The optimization problem can also be stated as the equivalent maximization problem; i.e. by changing the sign on Z. Any commands for solving the optimization problem can be used including, for example, linear programming commands.
  • A computer system of the invention can further include a user interface capable of receiving a representation of one or more reactions. A user interface of the invention can also be capable of sending at least one command for modifying the data structure, the constraint set or the commands for applying the constraint set to the data representation, or a combination thereof. The interface can be a graphic user interface having graphical means for making selections such as menus or dialog boxes. The interface can be arranged with layered screens accessible by making selections from a main screen. The user interface can provide access to other databases useful in the invention such as a metabolic reaction database or links to other databases having information relevant to the reactions or reactants in the reaction network data structure or to a multicellular organism's physiology, including Homo sapiens physiology. Also, the user interface can display a graphical representation of a reaction network or the results of a simulation using a model of the invention.
  • Once an initial reaction network data structure and set of constraints has been created, this model can be tested by preliminary simulation. During preliminary simulation, gaps in the network or “dead-ends” in which a metabolite can be produced but not consumed or where a metabolite can be consumed but not produced can be identified. Based on the results of preliminary simulations areas of the metabolic reconstruction that require an additional reaction can be identified. The determination of these gaps can be readily calculated through appropriate queries of the reaction network data structure and need not require the use of simulation strategies, however, simulation would be an alternative approach to locating such gaps.
  • In the preliminary simulation testing and model content refinement stage the existing model is subjected to a series of functional tests to determine if it can perform basic requirements such as the ability to produce the required biomass constituents and generate predictions concerning the basic physiological characteristics of the particular cell type being modeled. The more preliminary testing that is conducted the higher the quality of the model that will be generated. Typically, the majority of the simulations used in this stage of development will be single optimizations. A single optimization can be used to calculate a single flux distribution demonstrating how metabolic resources are routed determined from the solution to one optimization problem. An optimization problem can be solved using linear programming as demonstrated in the Examples below. The result can be viewed as a display of a flux distribution on a reaction map. Temporary reactions can be added to the network to determine if they should be included into the model based on modeling/simulation requirements.
  • Once a model of the invention is sufficiently complete with respect to the content of the reaction network data structure according to the criteria set forth above, the model can be used to simulate activity of one or more reactions in a reaction network. The results of a simulation can be displayed in a variety of formats including, for example, a table, graph, reaction network, flux distribution map or a phenotypic phase plane graph.
  • Thus, the invention provides a method for predicting a Homo sapiens physiological function. The method includes the steps of (a) providing a data structure relating a plurality of Homo sapiens reactants to a plurality of Homo sapiens reactions, wherein each of the Homo sapiens reactions includes a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (b) providing a constraint set for the plurality of Homo sapiens reactions; (c) providing an objective function, and (d) determining at least one flux distribution that minimizes or maximizes the objective function when the constraint set is applied to the data structure, thereby predicting a Homo sapiens physiological function.
  • A method for predicting a Homo sapiens physiological function can include the steps of (a) providing a data structure relating a plurality of Homo sapiens reactants to a plurality of Homo sapiens reactions, wherein each of the Homo sapiens reactions includes a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating the substrate and the product, and wherein at least one of the reactions is a regulated reaction; (b) providing a constraint set for the plurality of reactions, wherein the constraint set includes a variable constraint for the regulated reaction; (c) providing a condition-dependent value to the variable constraint; (d) providing an objective function, and (e) determining at least one flux distribution that minimizes or maximizes the objective function when the constraint set is applied to the data structure, thereby predicting a Homo sapiens physiological function.
  • Further, a method for predicting a physiological function of a multicellular organism also is provided. The method includes: (a) providing a first data structure relating a plurality of reactants to a plurality of reactions from a first cell, each of said reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (b) providing a second data structure relating a plurality of reactants to a plurality of reactions from a second cell, each of said reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (c) providing a third data structure relating a plurality of intra-system reactants to a plurality of intra-system reactions between said first and second cells, each of said intra-system reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (d) providing a constraint set for said plurality of reactions for said first, second and third data structures; (e) providing an objective function, and (f) determining at least one flux distribution that minimizes or maximizes an objective function when said constraint set is applied to said first and second data structures, wherein said at least one flux distribution is predictive of a physiological function of said first and second cells.
  • As used herein, the term “physiological function,” when used in reference to Homo sapiens, is intended to mean an activity of an organism as a whole, including a multicellular organism and/or a Homo sapiens organism or cell as a whole. An activity included in the term can be the magnitude or rate of a change from an initial state of, for example, two or more interacting cells or a Homo sapiens cell to a final state of the two or more interacting cells or the Homo sapiens cell. An activity included in the term can be, for example, growth, energy production, redox equivalent production, biomass production, development, or consumption of carbon nitrogen, sulfur, phosphate, hydrogen or oxygen. An activity can also be an output of a particular reaction that is determined or predicted in the context of substantially all of the reactions that affect the particular reaction in two or more interacting cells or a Homo sapiens cell, for example, or substantially all of the reactions that occur in a plurality of interacting cells such as a tissue, organ or organism, or substantially all of the reactions that occur in a Homo sapiens cell (e.g. muscle contraction). Examples of a particular reaction included in the term are production of biomass precursors, production of a protein, production of an amino acid, production of a purine, production of a pyrimidine, production of a lipid, production of a fatty acid, production of a cofactor or transport of a metabolite. A physiological function can include an emergent property which emerges from the whole but not from the sum of parts where the parts are observed in isolation (see for example, Palsson, Nat. Biotech 18:1147-1150 (2000)).
  • A physiological function of reactions within two or more interacting cells, including Homo sapiens reactions, can be determined using phase plane analysis of flux distributions. Phase planes are representations of the feasible set which can be presented in two or three dimensions. As an example, two parameters that describe the growth conditions such as substrate and oxygen uptake rates can be defined as two axes of a two-dimensional space. The optimal flux distribution can be calculated from a reaction network data structure and a set of constraints as set forth above for all points in this plane by repeatedly solving the linear programming problem while adjusting the exchange fluxes defining the two-dimensional space. A finite number of qualitatively different metabolic pathway utilization patterns can be identified in such a plane, and lines can be drawn to demarcate these regions. The demarcations defining the regions can be determined using shadow prices of linear optimization as described, for example in Chvatal, Linear Programming New York, W.H. Freeman and Co. (1983). The regions are referred to as regions of constant shadow price structure. The shadow prices define the intrinsic value of each reactant toward the objective function as a number that is either negative, zero, or positive and are graphed according to the uptake rates represented by the x and y axes. When the shadow prices become zero as the value of the uptake rates are changed there is a qualitative shift in the optimal reaction network.
  • One demarcation line in the phenotype phase plane is defined as the line of optimality (LO). This line represents the optimal relation between respective metabolic fluxes. The LO can be identified by varying the x-axis flux and calculating the optimal y-axis flux with the objective function defined as the growth flux. From the phenotype phase plane analysis the conditions under which a desired activity is optimal can be determined. The maximal uptake rates lead to the definition of a finite area of the plot that is the predicted outcome of a reaction network within the environmental conditions represented by the constraint set. Similar analyses can be performed in multiple dimensions where each dimension on the plot corresponds to a different uptake rate. These and other methods for using phase plane analysis, such as those described in Edwards et al., Biotech Bioeng. 77:27-36(2002), can be used to analyze the results of a simulation using an in silico Homo sapiens model of the invention.
  • A physiological function of Homo sapiens can also be determined using a reaction map to display a flux distribution. A reaction map of Homo sapiens can be used to view reaction networks at a variety of levels. In the case of a cellular metabolic reaction network a reaction map can contain the entire reaction complement representing a global perspective. Alternatively, a reaction map can focus on a particular region of metabolism such as a region corresponding to a reaction subsystem described above or even on an individual pathway or reaction.
  • Thus, the invention provides an apparatus that produces a representation of a Homo sapiens physiological function, wherein the representation is produced by a process including the steps of: (a) providing a data structure relating a plurality of Homo sapiens reactants to a plurality of Homo sapiens reactions, wherein each of the Homo sapiens reactions includes a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product; (b) providing a constraint set for the plurality of Homo sapiens reactions; (c) providing an objective function; (d) determining at least one flux distribution that minimizes or maximizes the objective function when the constraint set is applied to the data structure, thereby predicting a Homo sapiens physiological function, and (e) producing a representation of the activity of the one or more Homo sapiens reactions. Similarly, the invention provides an apparatus that produces a representation of two or more interacting cells, including a tissue, organ, physiological system or whole organism wherein data structures are provided relating a plurality of reactants to a plurality of reactions for each type of interacting cell and for one or more intra-system functions. A constraint set is provided for the plurality of reactions for the plurality of data structures as well as an objective function that minimizes or maximizes an objective function when the constraint set is applied to predict a physiological function of the two or more interacting cells. The apparatus produces a representation of the activity of one more reactions of the two or more interacting cells.
  • The methods of the invention can be used to determine the activity of a plurality of Homo sapiens reactions including, for example, biosynthesis of an amino acid, degradation of an amino acid, biosynthesis of a purine, biosynthesis of a pyrimidine, biosynthesis of a lipid, metabolism of a fatty acid, biosynthesis of a cofactor, transport of a metabolite and metabolism of an alternative carbon source. In addition, the methods can be used to determine the activity of one or more of the reactions described above or listed in Table 1.
  • The methods of the invention can be used to determine a phenotype of a Homo sapiens mutant or aberrant cellular interaction between two or more cells. The activity of one or more reactions can be determined using the methods described above, wherein the reaction network data structure lacks one or more gene-associated reactions that occur in Homo sapiens or in a multicellular organism or multicellular interaction. Alternatively, the methods can be used to determine the activity of one or more reactions when a reaction that does not naturally occur in the model of multicellular interactions or in Homo sapiens, for example, is added to the reaction network data structure. Deletion of a gene can also be represented in a model of the invention by constraining the flux through the reaction to zero, thereby allowing the reaction to remain within the data structure. Thus, simulations can be made to predict the effects of adding or removing genes to or from one or more cells within a multicellular interaction, including Homo sapiens and/or a Homo sapiens cell. The methods can be particularly useful for determining the effects of adding or deleting a gene that encodes for a gene product that performs a reaction in a peripheral metabolic pathway.
  • A drug target or target for any other agent that affects a function of a multicellular interaction, including a Homo sapiens function can be predicted using the methods of the invention. Such predictions can be made by removing a reaction to simulate total inhibition or prevention by a drug or agent. Alternatively, partial inhibition or reduction in the activity a particular reaction can be predicted by performing the methods with altered constraints. For example, reduced activity can be introduced into a model of the invention by altering the aj or bj values for the metabolic flux vector of a target reaction to reflect a finite maximum or minimum flux value corresponding to the level of inhibition. Similarly, the effects of activating a reaction, by initiating or increasing the activity of the reaction, can be predicted by performing the methods with a reaction network data structure lacking a particular reaction or by altering the aj or bj values for the metabolic flux vector of a target reaction to reflect a maximum or minimum flux value corresponding to the level of activation. The methods can be particularly useful for identifying a target in a peripheral metabolic pathway.
  • Once a reaction has been identified for which activation or inhibition produces a desired effect on a function of a multicellular interaction, including a Homo sapiens function, an enzyme or macromolecule that performs the reaction in the multicellular system or a gene that expresses the enzyme or macromolecule can be identified as a target for a drug or other agent. A candidate compound for a target identified by the methods of the invention can be isolated or synthesized using known methods. Such methods for isolating or synthesizing compounds can include, for example, rational design based on known properties of the target (see, for example, DeCamp et al., Protein Engineering Principles and Practice, Ed. Cleland and Craik, Wiley-Liss, New York, pp. 467-506 (1996)), screening the target against combinatorial libraries of compounds (see for example, Houghten et al., Nature, 354, 84-86 (1991); Dooley et al., Science, 266, 2019-2022 (1994), which describe an iterative approach, or R. Houghten et al. PCT/US91/08694 and U.S. Pat. No. 5,556,762 which describe the positional-scanning approach), or a combination of both to obtain focused libraries. Those skilled in the art will know or will be able to routinely determine assay conditions to be used in a screen based on properties of the target or activity assays known in the art.
  • A candidate drug or agent, whether identified by the methods described above or by other methods known in the art, can be validated using an in silico model or method of multicellular interactions, including a Homo sapiens model or method of the invention. The effect of a candidate drug or agent on physiological function can be predicted based on the activity for a target in the presence of the candidate drug or agent measured in vitro or in vivo. This activity can be represented in an in silico model of the multicellular system by adding a reaction to the model, removing a reaction from the model or adjusting a constraint for a reaction in the model to reflect the measured effect of the candidate drug or agent on the activity of the reaction. By running a simulation under these conditions the holistic effect of the candidate drug or agent on the physiological function of the multicellular system, including Homo sapiens physiological function can be predicted.
  • The methods of the invention can be used to determine the effects of one or more environmental components or conditions on an activity of, for example, a multicellular interaction, a tissue, organ, physiological function or a Homo sapiens cell. As set forth above an exchange reaction can be added to a reaction network data structure corresponding to uptake of an environmental component, release of a component to the environment, or other environmental demand. The effect of the environmental component or condition can be further investigated by running simulations with adjusted aj or bj values for the metabolic flux vector of the exchange reaction target reaction to reflect a finite maximum or minimum flux value corresponding to the effect of the environmental component or condition. The environmental component can be, for example an alternative carbon source or a metabolite that when added to the environment of a multicellular system, organism or Homo sapiens cell can be taken up and metabolized. The environmental component can also be a combination of components present for example in a minimal medium composition. Thus, the methods can be used to determine an optimal or minimal medium composition that is capable of supporting a particular activity of a multicellular interaction or system, including a particular activity of Homo sapiens.
  • The invention further provides a method for determining a set of environmental components to achieve a desired activity for Homo sapiens. The method includes the steps of (a) providing a data structure relating a plurality of Homo sapiens reactants to a plurality of Homo sapiens reactions, wherein each of the Homo sapiens reactions includes a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating the substrate and the product; (b) providing a constraint set for the plurality of Homo sapiens reactions; (c) applying the constraint set to the data representation, thereby determining the activity of one or more Homo sapiens reactions (d) determining the activity of one or more Homo sapiens reactions according to steps (a) through (c), wherein the constraint set includes an upper or lower bound on the amount of an environmental component and (e) repeating steps (a) through (c) with a changed constraint set, wherein the activity determined in step (e) is improved compared to the activity determined in step (d). Similarly, a method for determining a set of environmental components to achieve a desired activity for a multicellular interaction also is provided. The method includes providing a plurality of data structures relating a plurality of reactants to a plurality of reactions for each type of interacting cell and for one or more intra-system functions; providing a constraint set for the plurality of reactions for the plurality of data structures as well as providing an objective function that minimizes or maximizes an objective function when the constraint set is applied to predict a physiological function of the two or more interacting cells; determining the activity of one or more reactions within two or more interacting cells using a constraint set having an upper or lower bound on the amount of an environmental component and repeating these steps until the activity is improved.
  • It is understood that modifications which do not substantially affect the activity of the various embodiments of this invention are also included within the definition of the invention provided herein. Accordingly, the following examples are intended to illustrate but not limit the present invention.
  • Example I
  • This example shows the construction of a universal Homo sapiens metabolic reaction database, a Homo sapiens core metabolic reaction database and a Homo sapiens muscle cell metabolic reaction database. This example also shows the iterative model building process used to generate a Homo sapiens core metabolic model and a Homo sapiens muscle cell metabolic model.
  • A universal Homo sapiens reaction database was prepared from the genome databases and biochemical literature. The reaction database shown in Table 1 contains the following information:
      • Locus ID—the locus number of the gene found in the LocusLink website.
      • Gene Ab.—various abbreviations which are used for the gene.
      • Reaction Stoichiometry—includes all metabolites and direction of the reaction, as well as reversibility.
      • E.C.—The Enzyme Commission number.
  • Additional information included in the universal reaction database, although not shown in Table 1, included the chapter of Salway, supra (1999), where relevant reactions were found; the cellular location, if the reaction primarily occurs in a given compartment; the SWISS PROT identifier, which can be used to locate the gene record in SWISS PROT; the full name of the gene at the given locus; the chromosomal location of the gene; the Mendelian Inheritance in Man (MIM) data associated with the gene; and the tissue type, if the gene is primarily expressed in a certain tissue. Overall, 1130 metabolic enzyme- or transporter-encoding genes were included in the universal reaction database.
  • Fifty-nine reactions in the universal reaction database were identified and included based on biological data as found in Salway supra (1999), currently without genome annotation. Ten additional reactions, not described in the biochemical literature or genome annotation, were subsequently included in the reaction database following preliminary simulation testing and model content refinement. These 69 reactions are shown at the end of Table 1.
  • From the universal Homo sapiens reaction database shown in Table 1, a core metabolic reaction database was established, which included core metabolic reactions as well as some amino acid and fatty acid metabolic reactions, as described in Chapters 1, 3, 4, 7, 9, 10, 13, 17, 18 and 44 of J. G. Salway, Metabolism at a Glance, 2nd ed., Blackwell Science, Malden, Mass. (1999). The core metabolic reaction database included 211 unique reactions, accounting for 737 genes in the Homo sapiens genome. The core metabolic reaction database was used, although not in its entirety, to create the core metabolic model described in Example II.
  • To allow for the modeling of muscle cells, the core reaction database was expanded to include 446 unique reactions, accounting for 889 genes in the Homo sapiens genome. This skeletal muscle metabolic reaction database was used to create the skeletal muscle metabolic model described in Example II.
  • Once the core and muscle cell metabolic reaction databases were compiled, the reactions were represented as a metabolic network data structure, or “stoichiometric input file.” For example, the core metabolic network data structure shown in Table 2 contains 33 reversible reactions, 31 non-reversible reactions, 97 matrix columns and 52 unique enzymes. Each reaction in Table 2 is represented so as to indicate the substrate or substrates (a negative number) and the product or products (a positive number); the stoichiometry; the name of each reaction (the term following the zero); and whether the reaction is reversible (an R following the reaction name). A metabolite that appears in the mitochondria is indicated by an “m,” and a metabolite that appears in the extracellular space is indicated by an “ex.”
  • To perform a preliminary simulation or to simulate a physiological condition, a set of inputs and outputs has to be defined and the network objective function specified. To calculate the maximum ATP production of the Homo sapiens core metabolic network using glucose as a carbon source, a non-zero uptake value for glucose was assigned and ATP production was maximized as the objective function, using the representation shown in Table 2. The network's performance was examined by optimizing for the given objective function and the set of constraints defined in the input file, using flux balance analysis methods. The model was refined in an iterative manner by examining the results of the simulation and implementing the appropriate changes.
  • Using this iterative procedure, two metabolic reaction networks were generated, representing human core metabolism and human skeletal muscle cell metabolism.
  • Example II
  • This example shows how human metabolism can be accurately simulated using a Homo sapiens core metabolic model.
  • The human core metabolic reaction database shown in Table 3 was used in simulations of human core metabolism. This reaction database contains a total of 65 reactions, covering the classic biochemical pathways of glycolysis, the pentose phosphate pathway, the tricitric acid cycle, oxidative phosphorylation, glycogen storage, the malate/aspartate shuttle, the glycerol phosphate shuttle, and plasma and mitochondrial membrane transporters. The reaction network was divided into three compartments: the cytosol, mitochondria, and the extracellular space. The total number of metabolites in the network is 50, of which 35 also appear in the mitochondria. This core metabolic network accounts for 250 human genes.
  • To perform simulations using the core metabolic network, network properties such as the P/O ratio were specified using Salway, supra (1999) as a reference. Oxidation of NADH through the Electron Transport System (ETS) was set to generate 2.5 ATP molecules (i.e. a P/O ratio of 2.5 for NADH), and that of FADH2 was set to 1.5 ATP molecules (i.e. a P/O ratio of 1.5 for FADH2).
  • Using the core metabolic network, aerobic and anaerobic metabolisms were simulated in silico. Secretion of metabolic by-products was in agreement with the known physiological parameters. Maximum yield of all 12 precursor-metabolites (glucose-6-phosphate, fructose-6-phosphate, ribose-5-phosphate, erythrose-4-phosphate, triose phosphate, 3-phosphoglycerate, phosphoenolpyruvate, pyruvate, acetyl CoA, α-ketoglutarate, succinyl CoA, and oxaloacetate) was examined and none found to exceed the values of its theoretical yield.
  • Maximum ATP yield was also examined in the cytosol and mitochondria. Salway, supra (1999) reports that in the absence of membrane proton-coupled transport systems, the energy yield is 38 ATP molecules per molecule of glucose and otherwise 31 ATP molecules per molecule of glucose. The core metabolic model demonstrated the same values as described by Salway supra (1999). Energy yield in the mitochondria was determined to be 38 molecules of ATP per glucose molecule. This is equivalent to production of energy in the absence of proton-couple transporters across mitochondrial membrane since all the protons were utilized only in oxidative phosphorylation. In the cytosol, energy yield was calculated to be 30.5 molecules of ATP per glucose molecule. This value reflects the cost of metabolite exchange across the mitochondrial membrane as described by Salway, supra (1999).
  • Example III
  • This example shows how human muscle cell metabolism can be accurately simulated under various physiological and pathological conditions using a Homo sapiens muscle cell metabolic model.
  • As described in Example I, the core metabolic model was extended to also include all the major reactions occurring in the skeletal muscle cell, adding new functions to the classical metabolic pathways found in the core model, such as fatty acid synthesis and β-oxidation, triacylglycerol and phospholipid formation, and amino acid metabolism. Simulations were performed using the muscle cell reaction database shown in Table 4. The biochemical reactions were again compartmentalized into cytosolic and mitochondrial compartments.
  • To simulate physiological behavior of human skeletal muscle cells, an objective function had to be defined. Growth of muscle cells occurs in time scales of several hours to days. The time scale of interest in the simulation, however, was in the order of several to tens of minutes, reflecting the time period of metabolic changes during exercise. Thus, contraction (defined as, and related to energy production) was chosen to be the objective function, and no additional constraints were imposed to represent growth demands in the cell.
  • To study and test the behavior of the network, twelve physiological cases (Table 8) and five disease cases (Table 9) were examined. The input and output of metabolites were specified as indicated in Table 8, and maximum energy production and metabolite secretions were calculated and taken into account.
  • TABLE 8
    Metabolite
    Exchange
    1 2 3 4 5 6 7 8 9 10 11 12
    Glucose I I I I
    O2 I I I I I I
    Palmitate I I I I
    Glycogen I I I I
    Phospho- I I I I
    creatine
    Triacylglycerol I I I I
    Isoleucine I I
    Valine I I
    Hydroxy-
    butyrate
    Pyruvate
    Lactate
    Albumin
  • TABLE 9
    Disease Enzyme Deficiency Reaction Constrained
    McArdle's disease phosphorylase GBE1
    Tarui's disease phosphofructokianse PFKL
    Phosphoglycerate kinase phosphoglycerate kinase PGK1R
    deficiency
    Phosphoglycerate mutase phosphoglycerate mutase PGAM3R
    deficiency
    Lactate dehydrogenase Lactate dehyrogenase LDHAR
    deficiency
  • The skeletal muscle model was tested for utilization of various carbon sources available during various stages of exercise and food starvation (Table 8). The by-product secretion of the network in an aerobic to anaerobic shift was qualitatively compared to physiological outcome of exercise and found to exhibit the same general features such as secretion of fermentative by-products and lowered energy yield.
  • The network behavior was also examined for five disease cases (Table 9). The test cases were chosen based on their physiological relevance to the model's predictive capabilities. In brief, McArdle's disease is marked by the impairment of glycogen breakdown. Tarui's disease is characterized by a deficiency in phosphofructokinase. The remaining diseases examined are marked by a deficiency of metabolic enzymes phosphoglycerate kinase, phosphoglycerate mutase, and lactate dehydrogenase. In each case, the changes in flux and by-product secretion of metabolites were examined for an aerobic to anaerobic metabolic shift with glycogen and phosphocreatine as the sole carbon sources to the network and pyruvate, lactate, and albumin as the only metabolic by-products allowed to leave the system. To simulate the disease cases, the corresponding deficient enzyme was constrained to zero. In all cases, a severe reduction in energy production was demonstrated during exercise, representing the state of the disease as seen in clinical cases.
  • Example IV
  • This Example shows the construction and simulation of a multi-cellular model demonstrating the interactions between human adipocytes and monocytes.
  • The specific examples described above demonstrate the use a constraint-based approach in modeling metabolism in microbial organisms including prokaryotes such as E. coli and eukaryotes such as S. cerevisiae as well as for complex multicellular organisms requiring regulatory interactions such as humans. Described below is the modeling procedure, network content, and simulation results including network characteristics and metabolic performance of an integrated two-cell model of human adipocyte (fatty cell) and myocyte (muscle cell) using the compositions and methods of the invention. Simulations were performed to exemplify the coupled function of the two cell types during distinct physiological conditions corresponding to the coupled function of adipocytes and myocytes during sprint and marathon physiological conditions.
  • A human metabolic network model was reconstructed using biochemical, physiological, and genomic data as described previously. Briefly, the central metabolic network was used as a template for the construction of cell-specific models by adding biochemical reactions known to occur in specific cell-types of interest based on genomic, biochemical, and/or physiological information. Other methods for reconstructing the cell-specific models included reconstructing all the biochemical pathways and biochemical reactions that occur in the human metabolism regardless of their tissue specificity and location within the cell in a database and then reconstructing cell-, tissue-, organ-specific models by separating reactions that occur in specified cells, tissues, and/or organs based on genomic, physiological, biochemical, and/or high throughput data such as gene expression, proteomics, metabolomics, and other types of “omic” data. In this latter approach, in addition to the cell-, tissue-, and/or organ-specific reactions, reactions can be added to balance metabolites and represent the biochemistry, physiology, and genetics of the cells, tissues, organs, and/or whole human body. In the approach described below, the initial reconstruction of a central metabolic network followed by development of cell-specific models, the reconstruction of a generic central metabolic network is not a necessary step in reconstructing and modeling human metabolism. Rather, it is performed to accelerate the reconstruction process.
  • Implementation of the multi-cellular adipocyte-myocyte model is described below with reference to the reconstruction of the constituent components. In this regard, the reconstruction of a central human metabolic network is described first followed by the reconstruction procedures for fatty cell and muscle cell specific networks. The reconstruction procedure by which the two cell-specific models were combined to generate a multi-cellular model for human metabolism is then described.
  • Metabolic Network of Central Human Metabolism
  • The metabolic network of the central human metabolism was constructed as a template and a starting point for reconstructing more specific cell models. To construct a central metabolic network for human metabolism, a compendium of 1557 annotated human genes obtained from Kyoto Encyclopedia of Genes and Genomes KEGG, National Center for Biotechnology Information or NCBI, and the Universal Protein Resource or UniProt databases was used. In addition to the genomic and proteomic data, several primary textbooks and publications on the biochemistry of human metabolism also were used and included the Human Metabolism: Functional Diversity and Integration, Ed. by J. R. Bronk, Harlow, Addison, Wesley, Longman (1999); Textbook of Biochemistry with Clinical Correlations, Ed. by Thomas M. Devlin, New York, Wiley-Liss (2002), and Metabolism at a Glance, Ed. by J. G. Salway, Oxford, Malden, Mass., Blackwell Science (1999). The network reconstruction of human central metabolism included metabolic pathways for glycolysis, gluconeogenesis, citrate cycle (TCA cycle), pentose phosphate pathway, galactose, malonyl-CoA, lactate, and pyruvate metabolism. The methods described previously were similarly used for this reconstruction as well as those described below. Metabolic reactions were compartmentalized into extra-cellular space, cytosol, mitochondrion, and endoplasmic reticulum. In addition to the biochemical pathways, exchange reactions were included based on biochemical literature and physiological evidence to provide the transport of metabolites across different organelles and cytosolic membrane.
  • The completed central metabolic network for human metabolism is shown in FIGS. 5-1 through 5-9 where dashed lines indicate organelle, cell, or system boundary. The large dashed rectangle (black) represents the cytosolic membrane. The large dashed circle (red) represents the mitochondrial membrane and small dashed circle (green) represents the endoplasmic reticulum membrane. The human central metabolic network contains 80 reactions of which 25 are transporters and 60 unique metabolites 5. A representative example of a gene-protein-reaction association is shown in FIG. 6 where the open reading frame or ORF (7167) is associated to an mRNA transcript (TPI1). The transcript is then associated to a translated protein (Tpi1) that catalyzes a corresponding reaction (TPI).
  • Adipocyte Metabolic Network
  • Adipocytes are specialized cells for synthesizing and storing triacylglycerol. Triacylglycerols (TAG's) are synthesized from dihydroxyacetone phosphate and fatty acids in white adipose tissue. Triacylglycerol synthesized in adipocytes can be hydrolyzed (or degraded) into fatty acids and glycerol via specialized pathways in the fat cells. The fatty acids that are released from triacylglycerol leave the cell and are transported to other cell types such as myocytes for energy production. The fatty acid composition of triacylglycerol in human mammary adipose tissue has been experimentally measured (Raclot et al., 324:911-5 (1997)) and includes essential, non-essential, saturated, unsaturated, even-, and odd-chain fatty acids (Table 10).
  • TABLE 10
    Fatty acid composition of fat cell TAG in human, NEFA released by these
    cells in vitro, and relative mobilization (% NEFA/% TAG) of fatty acids.
    TAG NEFA Relative
    Fatty acid (weight %) (weight %) mobilization
    C12:0 0.50 ± 0.07 0.45 ± 0.06 0.88 ± 0.02
    C14:0 3.08 ± 0.13 2.94 ± 0.15 0.94 ± 0.01
    C14:1,n-7 0.03 ± 0.00 0.03 ± 0.00 1.07 ± 0.14
    C14:1,n-5 0.20 ± 0.01 0.19 ± 0.02 0.96 ± 0.03
    C15:0 0.33 ± 0.02 0.35 ± 0.02 1.05 ± 0.02
    C16:0 22.79 ± 0.56  23.51 ± 0.74  1.02 ± 0.01
    C16:1,n-9 0.54 ± 0.01   0.42 ± 0.02*** 0.77 ± 0.01
    C16:1,n-7 2.77 ± 0.21  3.69 ± 0.34* 1.31 ± 0.02
    C17:1,n-8 0.29 ± 0.02  0.36 ± 0.02* 1.21 ± 0.03
    C18:0 6.67 ± 0.35 6.41 ± 1.39 0.95 ± 0.06
    C18:1,n-9 40.79 ± 0.52  39.77 ± 0.57  0.96 ± 0.01
    C18:1,n-7 1.90 ± 0.05 2.12 ± 0.10 1.10 ± 0.03
    C18:1,n-5 0.27 ± 0.01 0.31 ± 0.03 1.12 ± 0.04
    C18:2,n-6 16.23 ± 0.86  16.21 ± 0.62  0.99 ± 0.01
    C18:3,n-6 0.04 ± 0.00 0.05 ± 0.01 1.27 ± 0.07
    C18:3,n-3 0.51 ± 0.02   0.75 ± 0.03*** 1.43 ± 0.03
    C20:0 0.21 ± 0.02   0.10 ± 0.01*** 0.47 ± 0.04
    C20:1,n-11 0.17 ± 0.01   0.11 ± 0.01*** 0.66 ± 0.03
    C20:1,n-9 0.84 ± 0.02   0.53 ± 0.02*** 0.62 ± 0.01
    C20:1,n-7 0.03 ± 0.00  0.02 ± 0.00* 0.67 ± 0.03
    C20:2,n-9 0.04 ± 0.00  0.02 ± 0.00** 0.63 ± 0.06
    C20:2,n-6 0.31 ± 0.02  0.26 ± 0.01* 0.82 ± 0.04
    C20:3,n-6 0.26 ± 0.03 0.24 ± 0.03 0.90 ± 0.05
    C20:3,n-3 0.03 ± 0.00 0.03 ± 0.00 0.90 ± 0.06
    C20:4,n-6 0.35 ± 0.03   0.57 ± 0.04*** 1.60 ± 0.04
    C20:4,n-3 0.03 ± 0.01 0.04 ± 0.01 1.13 ± 0.16
    C20:5,n-3 0.04 ± 0.01   0.10 ± 0.01*** 2.25 ± 0.08
    C22:0 0.04 ± 0.01  0.02 ± 0.01* 0.42 ± 0.05
    C22:1,n-11 0.03 ± 0.01  0.01 ± 0.00* 0.37 ± 0.02
    C22:1,n-9 0.07 ± 0.01  0.03 ± 0.00** 0.45 ± 0.03
    C22:4,n-6 0.17 ± 0.02  0.10 ± 0.01** 0.58 ± 0.03
    C22:5,n-6 0.02 ± 0.01 0.01 ± 0.00 0.59 ± 0.05
    C22:5,n-3 0.20 ± 0.03  0.11 ± 0.01** 0.55 ± 0.02
    C22:6,n-3 0.21 ± 0.04  0.14 ± 0.02* 0.65 ± 0.04
    *P < 0.05;
    **P < 0.01;
    ***P < 0.001
  • The adipocyte metabolic model was constructed by adding the non-essential saturated, unsaturated, even- and odd-chain fatty acid biosynthetic pathways to the central metabolic network for 21 of the fatty acids listed in Table 10. The remaining 13 essential fatty acids were supplied to the cell via the extra-cellular space, representing the nutritional intake from the environment. Pathway for biosynthesis of triacylglycerol (TAG) from all 34 fatty acids was included to account for the formation and storage of TAG in adipocytes. Reactions for hydrolysis of TAG into fatty acids were also included to represent TAG degradation. In addition to fatty acid synthesis and TAG biosynthesis and degradation, transport reactions were included to allow for the release of fatty acids from intra-cellular space to the environment.
  • The metabolic model of an adipocyte cell contains a total of 198 reactions of which 63 are transporters. The adipocyte cell model is shown in FIGS. 7-1 through 7-35 where dashed lines indicate organelle, cell, or system boundary. The large dashed rectangle (yellow) represents the adipocyte cytosolic membrane. The two large dashed circles (red) represent the mitochondrial membrane and the small dashed circle at the top (green) represents the endoplasmic reticulum membrane. As shown, metabolic reactions were compartmentalized into extra-cellular, cytosolic, mitochondrial, and endoplasmic reticulum. As described above, the extra-cellular space represents the environment outside the cell, which can include the space outside the body, connective tissues, and interstitial space between cells.
  • Myocyte Metabolic Network
  • The energy required for muscle contraction is generally supplied by glucose, stored glycogen, phosphocreatine, and fatty acids. The myocyte model was constructed by adding phosphocreatine kinase reaction, myosin-actin activation mechanism, and β-oxidation pathway to the central metabolic network. Muscle contraction was represented by a sequential conversion of myoactin to myosin-ATP, myosin-ATP to myosin-ADP-P, myosin-ADP-P to myosin-actin-ADP-P complex, myosin-actin-ADP-P to myoactin, and subsequently the formation of muscle contraction as shown in FIG. 8.
  • The conversion of myoactin to myosin-actin-ADP-P complex and muscle contraction results in a net conversion of ATP and H2O to ADP, H+, and Pi.
  • The complete reconstructed metabolic model for myocyte cell metabolism is shown in FIGS. 9-1 through 9-35 where dashed lines indicate organelle, cell, or system boundary. The large dashed rectangle (brown) represents the myocyte cytosolic membrane. The two large dashed circles (red) represent the mitochondrial membrane. The medium sized dashed circle (purple) represents the peroxisomal membrane and the small dashed circle (green) represents the endoplasmic reticulum membrane. The myocyte network contains a total of 205 reactions of which 46 are transport reactions. Reactions for utilizing phosphocreatine as well as selected pathways for β-oxidation of saturated, unsaturated, even- and odd-chain fatty acids and their intermediates were also included in the model and are shown in FIGS. 9-1 through 9-35. As with the previous network models, metabolic reactions were compartmentalized into extra-cellular, cytosolic, mitochondrial, peroxisomal, and endoplasmic reticulum.
  • Multi-Cellular Adipocyte-Myocyte Reconstruction
  • To generate a multi-cellular model for human metabolism, the metabolic function of the two models of adipocyte and myocyte were integrated by reconstructing a model that includes all the metabolic reactions in the two individual cell types. The interaction of the two cell types were then represented within an “intra-system” space, which represents the connective tissues such as blood, urine, and interstitial space, and an outside environment or “extra-system” space. To represent the uptake of metabolites and essential fatty acids from the environment, appropriate transport reactions were added to exchange metabolites across the extra-system boundary. Additional reactions also were added to balance metabolites in the intra-system space by including the bicarbonate and ammonia buffer systems as they function in the kidneys. These reactions were initially omitted but were added to improve the model once the requirement for the integrated system to buffer extracellular protons in the interstitial space became apparent once simulation testing began. The combined adipocyte-myocyte model contains 430 reactions and 240 unique metabolites. The complete reconstruction is shown in FIGS. 10-1 through 10-70 and a summary of the reactions is set forth in Table 11. A substantially complete listing of all the reactions set forth in FIGS. 10-1 through 10-70 is set forth below in Table 15.
  • TABLE 11
    Network properties of central metabolic network,
    adipocyte, myocyte, and multi-cell adipocyte-myocyte models.
    Model Reactions Transporters Compounds
    Central Metabolism 80 25 60
    Adipocyte 198 63 150
    Myocyte 205 46 167
    Adipocyte-Myocyte 430 135 240
  • In FIGS. 10-1 through 10-70, dashed lines again indicate organelle, cell, or system boundaries. The outer most large dashed rectangle (black) separates the environment inside and outside the human body. The two interior dashed rectangles represents the adipocyte cytosolic membrane (top, yellow) and the myocyte cytosolic membrane (bottom, brown). The pair of larger dashed circles within the adipocyte and myocyte cytosol (red) represent the mitochondrial membrane. The medium sized dashed circle in the myocyte cytosol (purple) represents the peroxisomal membrane and small dashed circle within the adipocyte and myocyte cytosol (green) represent the endoplasmic reticulum membrane.
  • Metabolic Simulations
  • The computational and infrastructure requirements for producing the integrated multi-cellular model were assessed by examining the network properties of first, the cell-specific models, and then the integrated multi-cellular reconstruction.
  • Metabolic Model of Central Human Metabolism
  • The metabolic capabilities of the central human model was determined through computation of maximum yield of the 12 precursor metabolites per glucose. The results are shown in Table 12. In all cases, the network's yield was less or equal to the maximum theoretical values except for succinyl-CoA. In the case of succinyl-CoA, a higher yield was possible by incorporating CO2 via pyruvate carboxylase reaction, PCm. In addition to precursor metabolite yields, the maximum ATP yield per mole of glucose was computed in the network. The maximum ATP yield for the central human metabolism was computed to be 31.5 mol ATP/mol glucose, which is consistent with previously calculated values (Vo et al., J. Biol. Chem. 279:39532-40. (2004)).
  • TABLE 12
    Maximum theoretical and central human metabolic network yields for the
    precursor metabolites per glucose. Units are in mol/mol glucose.
    Precursor Metabolites Theoretical Central Metabolism
    Glucose 6-P 1 0.94
    Fructose 6-P 1 0.94
    Ribose 5-P 1.2 1.115
    Erythrose 4-P 1.5 1.37
    Glyceraldehyde 3-P 2 1.775
    3-P Glycerate 2 2
    Phosphoenolpyruvate 2 2
    Pyruvate 2 2
    Oxaloacetate, mitochondrial 2 1.969
    Acetyl-CoA, mitochondrial 2 2
    aKeto-glutarate, mitochondrial 1 1
    Succinyl-CoA, mitochondrial 1 1.595
  • The biomass demand in living cells is a requirement for the production of biosynthetic components such as amino acids, lipids and other molecules that are needed to provide cell integrity, maintenance, and growth. All the biosynthetic components were made from the 12 precursor metabolites in the central metabolism shown in Table 12. The rate of growth and biomass maintenance in mammalian cells however is typically much lower than the rate of metabolic activities. Thus to represent the cells' biosynthetic requirement, a small flux demand was imposed for the production of the 12 precursor metabolites while maximizing for ATP. In the absence of experimental measurements, the capability of the network to meet the biosynthetic requirements was examined by constructing a reaction in which all the precursor metabolites were made simultaneously with stoichiometric coefficients of one as set forth in the reaction below:

  • Precursor Demand: 3pg[c]+accoa[m]+akg[m]+e4p[c]+f6p[c]+g3p[c]+g6p[c]+oaa[m]+pep[c]+pyr[c]+r5p[c]+succoa[m]→(2)coa[m]
  • In the absence of quantitative measurement, the above reaction serves to demonstrate the ability of the network to meet both biomass and energy requirements in the cell simultaneously. The maximum ATP yield for the central metabolism with a demand of 0.01 mmol/g DW of precursor metabolites was computed to be 29.0, demonstrating that the energy and carbon requirements for precursor metabolite generation, as expected, reduce the maximum energy production in the cell and this amount can be quantified using the reconstructed model.
  • Triacylglycerol Storage and Utilization in Adipocyte Tissue
  • As described previously, a main function of adipocyte is to synthesize, store, and hydrolyze triacylglycerols. The stored TAG can be used to generate ATP during starvation or under high-energy demand conditions. TAG hydrolysis results in the formation of fatty acids and glycerol in adipocyte. Fatty acids are transported to other tissues such as the muscle tissue where they can be utilized to generate energy. Glycerol is utilized further by the liver and other tissues where it is converted into glycerol phosphate and enters glycolytic pathway.
  • To simulate the storage of triacylglycerol from glucose in adipocyte, TAG synthesis was simulated by maximizing an internal demand for cytosolic triacylglycerol. The maximum yield of triacylglycerol per glucose was computed to be 0.06 mol TAG/mol glucose, without any biomass demand. To demonstrate how the stored TAG can be reutilized to produce fatty acids, the influx of all other carbon sources including glucose was constrained to zero and glycerol secretion, which is assumed to be taken up by the liver, was maximized. When 2 mol of cytosolic proton was allowed to leave the system, a glycerol yield of 1 mol glycerol/mol TAG or 100% was computed. The excess two protons were formed in TAG degradation pathway. As shown in FIG. 11, degradation of TAG was performed in the following three steps: (1) TRIGH_ac_HS_ub; (2) 12DGRH_ac_HS_ub, and (3) MGLYCH_ac_HS_ub). Glycerol generated as an end product of this pathway was transported out of the cell via a proton-coupled symport mechanism. TAG was hydrolyzed completely to fatty acids and glycerol in three steps and in each step one proton is released. Glycerol transport was coupled to one proton. Thus, a net amount of two protons were generated per mol TAG degraded.
  • To balance protons, an ATPase reaction across the cytosolic membrane was used. However, since the β-oxidative pathways were not included in this adipocyte model, this network is unable to use membrane bound ATPase to balance the internal protons. When β-oxidative pathways are added to the adipocyte model, the model can completely balance protons.
  • In addition to triacylglycerol synthesis and hydrolysis, the maximum ATP yield on glucose (YATP/glucose) was computed in the adipocyte model. As for the central human metabolic network, YATP/glucose was 31.5 mol ATP/mol glucose.
  • Muscle Contraction During Aerobic and Anaerobic Exercise
  • The required energy in muscle tissue is generally supplied by glucose, stored glycogen, and phosphocreatine. During anaerobic exercise such as a sprint, for example, the blood vessels in the muscle tissue are compressed and the cells are isolated from the rest of the body (Devlin, supra). This compression restricts the oxygen supply to the tissue and enforces anaerobic energy metabolism in the cell. As a result, lactate is generated to balance the redox potential and must be secreted out of the cell. In the liver, lactate is converted into glucose. However, rapid muscle contraction and decreased blood flow to the muscle tissue cause lactate accumulation during anaerobic exercise and quickly impairs muscle contraction. During starvation or under high-energy demands, the glucose and glycogen storage of the muscle tissue quickly depletes and the energy storage in triacylglycerol molecules supplied by fatty cells is used to generate ATP.
  • To simulate the muscle physiology at steady state, phosphocreatine kinase reaction, myosin-actin activation mechanism, and β-oxidation pathway were included in the central metabolic network. The physiological function of muscle tissue was simulated by determining the maximum amount of contraction that is generated from the energy supplied by glucose, stored glycogen, phosphocreatine, and supplied fatty acids.
  • The metabolic capabilities of the myocyte model were assessed by first computing the maximum ATP yield on glucose. As for the central human metabolic network, YATP/glucose was 31.5 mol ATP/mol glucose. The muscle contraction was also examined with glucose as the sole carbon source. Maximum muscle contraction with glucose was computed to be 31.5 mol/mol glucose in aerobic and 2 mol/mol glucose in anaerobic condition. Lactate was secreted as a byproduct during anaerobic contraction (Yield lactate/glucose=2 mol/mol).
  • As lactate accumulates during anaerobic metabolism, its secretion rate quickly fails to meet the demand to release lactate into the blood. To simulation the impairment of muscle contraction in anaerobic exercise, the maximum lactate secretion rate was constrained to 75%, 50%, 25%, and 0% of its maximum value under anaerobic condition. The results using these different constraints are shown in FIG. 12 where the time is shown as an arbitrary unit, rate of contraction and lactate secretion are in mols per cell mass per unit time, r corresponds to rate and lac corresponds to lactate. The results show that as more lactate accumulates in anaerobic metabolism, the maximum allowable lactate secretion decreases and maximum muscle contraction decreased proportionally.
  • The muscle contraction was simulated also with stored glycogen and phosphocreatine as the energy source. The maximum contraction for glycogen was computed to be 32.5 mol/mol glycogen in aerobic and 3 mol/mol glycogen in anaerobic condition. The observed difference between the maximum contraction generated by glycogen in comparison to glucose arises from the absence of the phosphorylation or glucokinase step in the first step of glycolysis. The results of glycogen versus glucose utilization are illustrated in FIG. 13 where the glycogen utilization pathway is shown as the thick bent arrow on the left (red) and the glucose utilization pathway is shown as the thick straight arrow on the right (blue). The dashed circle (green) represents the endoplasmic reticulum membrane. The maximum contraction from phosphocreatine under both aerobic and anaerobic conditions was computed to be 1 mol/mol phosphocreatine. The energy generated from phosphocreatine is independent of the energy produced through oxidative phosphorylation and thus was computed to be the same in both aerobic and anaerobic conditions.
  • In addition, β-oxidative pathways in the myocyte tissue were examined by supplying the network with eicosanoate (n-C20:0), octadecenoate (C18:1, n-9), and pentadecanoate (C15:0) as examples of fatty acid oxidation of odd- and even-chain, and saturated and unsaturated fatty acids. The results are shown in Table 13 and demonstrate that maximum contraction in the myocyte model was 134 mol/mol for eicosanoate, 118.5 mol/mol for octadecenoate, and 98.5 mol/mol for pentadecanoate. The results also show that on a carbon-mole basis, all the fatty acids yielded approximately the same contraction, which was equivalent to ATP yield. Contraction was observed to be larger in terms of carbon yield than that generated from glucose (i.e. ˜6.6 mol ATP/C-mol fatty acid in comparison to 5.3 mol ATP/C-mol glucose). The maximum ATP yield for palmitate (C16:0) was also computed to be 106 mol ATP/mol palmitate, which was consistent with the previously calculated values (Vo et al, supra). One mol of cytosolic protons per mol of fatty acid was supplied to the network for fatty acid oxidation.
  • TABLE 13
    Maximum contraction in the myocyte model given different fatty acids
    Maximum Maximum
    Contraction Contraction
    Fatty Acid Abbreviation* (mol/mol fatty acid) (mol/C-mol)
    Eicosanoate C20:0 134 6.7
    Octadecenoate C18:1, n-9 118.5 6.6
    Palmitate C16:0 106 6.6
    Pentadecanoate C15:0 98.5 6.6
    *Abbreviation indicates: number of carbons in the fatty acid, number of double bonds, carbon number where the 1st double bond appears if the fatty acid is unsaturated.
  • A unit of proton per fatty acid is required in the network to balance fatty acyl CoA formation in the cell as illustrated in the following reaction:
  • Fatty Acid CoA Ligase: Fatty Acid + ATP + CoA → Fatty Acyl-CoA + AMP + PPi
    Adenylate Kinase: AMP + ATP  
    Figure US20150302141A1-20151022-P00001
      (2) ADP
    Inorganic Diphosphatase: PPi + H2O → H+ + (2) Pi
    Net: Fatty Acid + CoA + (2) ATP + H2O → Fatty Acyl-CoA + (2)O ADP + (2) Pi + H+
  • With respect to ATP balance (i.e. ATP+H2O→ADP+Pi+H+), the net reaction has one mol less H2O and H+. Water can freely diffuse through the membrane. However, cell membrane is impermeable to free protons and thus protons were balanced in all compartments. The proton requirement in the cell can be fulfilled with a proton-coupled fatty acid transporter. It has been observed that the proton electrochemical gradient across the inner membrane plays a crucial role in energizing the long-chain fatty acid transport apparatus in E. coli and the proton electrochemical gradient across the inner membrane is required for optimal fatty acid transport (DiRusso et al., Mol. Cell. Biochem. 192:41-52 (1999)). Fatty acid transporters in S. cerevisiae have also been studied, however, no evidence is currently available on the mechanism of transport. When a proton coupled fatty acid transporter was used in the model, the requirement for supplying a mol of proton to the system was eliminated.
  • Adipocyte-Myocyte Coupled Functions
  • Muscle cells largely rely on their stored glycogen and phosphocreatine content. During aerobic exercise, however, glucose, glycogen, and phosphocreatine storage of muscle cells are depleted and energy generation in myocytes is achieved by fatty acid oxidation. Lipolysis or lipid degradation proceeds in muscle cells following the transfer of fatty acids from adipocytes to myocytes via blood.
  • Modeling of multi-cellular metabolism was performed using a constraint-based approach as described herein where the metabolic networks of adipocyte and myocyte were combined into a multi-cellular metabolic model as shown in FIGS. 10-1 through 10-70. The integrated model was assessed by computing the network energy requirements during anaerobic exercise such as that corresponding to a sprint and aerobic exercise such as that corresponding to a marathon. From a purely additive perspective, combining all of the reactions from the adipocyte model with those from the myocyte model was initially performed as a sufficient indicator for the combined network to compute integrated physiological results. However, with the two models strictly combined in this manner they were deficient at computing integrated functions such as those described below and, in particular, the results described in the “Muscle Contraction in a Marathon” section below. Addition of buffer systems for bicarbonate and ammonia allowed the combined model to function more efficiently and predictably. In retrospect, the inclusion of intra-system reactions is consistent with the role that, for example, the kidney plays in integrated metabolic physiology.
  • Simulation of an Integrated Model for Muscle Contraction During a Sprint:
  • The energy requirements of myocytes in a sprint are extremely high and supplied primarily from the fuel present in the muscle. In addition, oxygen cannot be transported to the cells fast enough to trigger an aerobic metabolism. It has been estimated that only 5% of the energy in a sprint is supplied via oxidative phosphorylation and the remaining ATP is generated from anaerobic metabolism from stored glycogen and phosphocreatine (Biochemical and Physiological Aspects of Human Nutrition, Philadelphia, Ed. by M.H. Stipanuk, W.B. Saunders, (2000)).
  • To simulate the metabolic activity of the muscle in a sprint, the maximum muscle contraction in an aerobic condition was computed by supplying the multi-cellular model with glucose, glycogen, and phosphocreatine as shown in Table 14. In addition, muscle contraction was simulated under anaerobic condition by constraining the oxygen supply to zero. Maximum contraction was computed to be the same as in the isolated myocyte model, as expected, demonstrating that the integrated model retains the functionalities observed in the single-cell model.
  • TABLE 14
    Simulation results in the adipocyte-myocyte integrated model.1
    Objective (Cell Aerobic Anaerobic
    Carbon Source Type) mol/mol carbon source
    Glucose Contraction (M) 31.5 2
    Glycogen Contraction (M) 32.5 3
    Phosphocreatine Contraction (M) 1  1
    Glucose ATP synthesis (A) 32.5
    Glucose TAG synthesis (A)  0.06
    TAG Glycerol (I)  1*
    TAG supplying C12:0, Contraction (M) 253.9 
    C14:0, C15:0, C16:0, C18:0,
    C18:1 n-9, and C20:0
    *Two protons were allowed to leave the cytosol (see section “Triacylglycerol Storage and Utilization in Adipocyte Tissue”)
    — Not relevant
    1M, myocyte; A, adipocyte; I, intra-system; TAG, triacylglycerol; C12:0, dodecanoate; C14:0, tetradecanoate; C15:0, pentadecanoate; C16:0, palmitate, C18:0, octadecanoate; C18:1 n-9, octadecenoate; C20:0, eicosanoate
  • Simulation of an Integrated Model for Muscle Contraction During a Marathon:
  • The total energy expenditure in a marathon is about 12,000 kJ or 2868 kcal, which is equivalent to burning about 750 g of carbohydrate or 330 g of fat (Stipanuk, supra). Since the total stored carbohydrate in the body is only about 400 to 900 g, the mobilized fatty acids from adipose tissue provide an important part of the supplied energy to the muscle cells in an aerobic metabolism and especially in a marathon.
  • To simulate the aerobic oxidation of fatty acid in the muscle cells, the integrated model was first demonstrated to be able to synthesize and store triacylglycerol in the adipocyte compartment when supplied by glucose. As for the single cell model, the integrated adipocyte-myocyte network was able to store TAG in adipocyte compartment. The results are shown in Table 14. In addition, TAG degradation and fatty acid mobilization to the blood was simulated by maximizing glycerol secretion in the intra-system space generated from the stored TAG in adipocyte. As with the single cell model, TAG hydrolysis was simulated with the integrated adipocyte-myocyte model and maximum glycerol secretion rate was shown to be the same.
  • To demonstrate the coupled function of the two cell types, muscle contraction in an aerobic exercise was simulated by constraining all other alternative carbon sources including glucose, stored glycogen, and phosphocreatine to zero and supplying adipocyte with stored triacylglycerol as an energy source. Exchange fluxes were included to ensure the proper transfer of fatty acids between the two models. The maximum muscle contraction in the network that contains β-oxidative pathways for fatty acids C12:0, C14:0, C15:0, C, 16:0, C18:0, C18:1 n-9, and C20:0 was simulated and computed to be 253.9 mol/mol TAG. The total contraction in this simulation is the sum of maximum contraction that is generated if the model was supplied with each fatty acid individually. The results from using the integrated model demonstrated that energy generated in the muscle cell from triacylglycerol is produced in an additive fashion and metabolite balance in the two cell types does not reduce the energy production in the cell.
  • These studies further demonstrate the application of a constraint-based approach to modeling multi-cellular integrated metabolic models. The results also indicate that modeling multi-cellular networks can be optimized by incorporating intra-system reactions such as the bicarbonate and ammonia buffer systems into the integrated adipocyte-myocyte model. The reconstructed models and simulation results also demonstrated that metabolic functions of various cell types can be studied, understood and reproduced using the methods of the invention. Furthermore, coupling of the functions of multiple cell types in a system was demonstrated through the transport of various metabolites and the coupled function of different cell types were studied by imposing biologically appropriate objective function. Finally, the ability to predict further network modifications, such as the transport mechanism of fatty acids into myocyte, using the reconstructed models also was demonstrated. These results also indicate that multi-cellular modeling can be extended to the modeling of more than two cells and which correspond to various cell types including the same specie or among multiple different species, tissues, organs, and whole body by including additional genomic, biochemical, physiological, and high throughput datasets.
  • Throughout this application various publications have been referenced within parentheses. The disclosures of these publications in their entireties are hereby incorporated by reference in this application in order to more fully describe the state of the art to which this invention pertains.
  • Although the invention has been described with reference to the disclosed embodiments, those skilled in the art will readily appreciate that the specific examples and studies detailed above are only illustrative of the invention. It should be understood that various modifications can be made without departing from the spirit of the invention. Accordingly, the invention is limited only by the following claims.
  • TABLE 1
    Locus ID Gene Ab. Reaction Stolchiometry E.C.
    1. Carbohydrate Metabolism
    1.1 Glycolysis/Gluconeogenesis [PATH: hsa00010]
    3098 HK1 GLC + ATP -> G6P + ADP 2.7.1.1
    3099 HK2 GLC + ATP -> G6P + ADP 2.7.1.1
    3101 HK3 GLC + ATP -> G6P + ADP 2.7.1.1
    2645 GCK, HK4, MODY2, NIDDM GLC + ATP -> G6P + ADP 2.7.1.2
    2538 G6PC, G6PT G6P + H2O -> GLC + PI 3.1.3.9
    21321 GPI G6P <-> F6P 5.3.1.9
    5211 PFKL F6P + ATP -> FDP + ADP 2.7.1.11
    5213 PFKM F6P + ATP -> FDP + ADP 2.7.1.11
    5214 PFKP, PFK-C F6P + ATP -> FDP + ADP 2.7.1.11
    5215 PFKX F6P + ATP -> FDP + ADP 2.7.1.11
    2203 FBP1, FBP FDP + H2O -> F6P + PI 3.1.3.11
    8789 FBP2 FDP + H2O -> F6P + PI 3.1.3.11
    226 ALDOA FDP <-> T3P2 + T3P1 4.1.2.13
    229 ALDOB FDP <-> T3P2 + T3P1 4.1.2.13
    230 ALDOC FDP <-> T3P2 + T3P1 4.1.2.13
    7167 TPI1 T3P2 <-> T3P1 5.3.1.1
    2597 GAPD, GAPDH T3P1 + PI + NAD <-> NADH + 13PDG 1.2.1.12
    28330 GAPDS, GAPDH-2 T3P1 + PI + NAD <-> NADH + 13PDG 1.2.1.12
    5230 PGK1, PGKA 13PDG + ADP <-> 3PG + ATP 2.7.2.3
    5233 PGK2 13PDG + ADP <-> 3PG + ATP 2.7.2.3
    5223 PGAM1, PGAMA 13PDG -> 23PDG 5.4.2.4
    23PDG + H2O -> 3PG + PI 3.1.3.13
    3PG <-> 2PG 5.4.2.1
    5224 PGAM2, PGAMM 13PDG <-> 23PDG 5.4.2.4
    23PDG + H2O -> 3PG + PI 3.1.3.13
    3PG <-> 2PG 5.4.2.1
    669 BPGM 13PDG <-> 23PDG 5.4.2.4
    23PDG + H2O <-> 3PG + PI 3.1.3.13
    3PG <-> 2PG 5.4.2.1
    2023 ENO1, PPH, ENO1L1 2PG <-> PEP + 1-120 4.2.1.11
    2026 ENO2 2PG <-> PEP + 1420 4.2.1.11
    2027 ENO3 2PG <-> PEP + 1420 4.2.1.11
    26237 ENO1B 2PG <-> PEP + H2O 4.2.1.11
    5313 PKLR, PKI PEP + ADP -> PYR + ATP 2.7.1.40
    5315 PKM2, PK3, THBP1, OIP3 PEP + ADP -> PYR + ATP 2.7.1.40
    5160 PDHA1, PHE1A, PDHA PYRm + COAm + NADm -> + NADHm + CO2m + ACCOAm 1.2.4.1
    5161 PDHA2, PDHAL PYRm + COAm + NADm -> + NADHm + CO2m + ACCOAm 12.4.1
    5162 PDHB PYRm + COAm + NADm -> + NADHm + CO2m + ACCOAm 1.2.4.1
    1737 DLAT, DLTA, PDC-E2 PYRm + COAm + NADm -> + NADHm + CO2m + ACCOAm 2.3.1.12
    8050 PDX1, E3BP PYRm + COAm + NADm -> + NADHm + CO2m + ACCOAm 2.3.1.12
    3939 LDHA, LDH1 NAD + LAC <-> PYR + NADH 1.1.1.27
    3945 LDHB NAD + LAC <-> PYR + NADH 1.1.1.27
    3946 LDHC, LDH3 NAD + LAC <-> PYR + NADH 1.1.1.27
    5235 PGM1 G1P <-> G6P 5.4.2.2
    5237 PGM2 G1P <-> G6P 5.4.2.2
    5238 PGM3 G1P <-> G6P 5.4.2.2
    1738 DLD, LAD, PHE3, DLDH, E3 DLIPOm + FADm <-> LIPOm + FADH2m 1.8.1.4
    124 ADH1 ETH + NAD <-> ACAL + NADH 1.1.1.1
    125 ADH2 ETH + NAD <-> ACAL + NADH 1.1.1.1
    126 ADH3 ETH + NAD <-> ACAL + NADH 1.1.1.1
    127 ADH4 ETH + NAD <-> ACAL + NADH 1.1.1.1
    128 ADH5 FALD + RGT + NAD <-> FGT + NADH 1.2.1.1
    ETH + NAD <-> ACAL + NADH 1.1.1.1
    130 ADH6 ETH + WAD <-> ACAL + NADH 1.1.1.1
    131 ADH7 ETH + NAD <-> ACAL + NADH 1.1.1.1
    10327 AKR1A1, ALR, ALDR1 1.1.12
    97 ACYP1 3.6.1.7
    98 ACYP2 3.6.1.7
    1.2 Citrate cycle (TCA cycle) PATH: hsa00020
    1431 CS ACCOAm + OAm + H2Om -> COAm + CITm 4.1.3.7
    48 ACO1, IREB1, IRP1 CIT <-> ICIT 4.2.1.3
    50 ACO2 CITm <-> ICITm 4.2.1.3
    3417 IDH1 ICIT + NADP -> NADPH + CO2 + AKG 1.1.1.42
    3418 IDH2 ICITm + NADPm -> NADPHm + CO2m + AKGm 1.1.1.42
    3419 IDH3A ICITm + NADm -> CO2m + NADHm + AKGm 1,1.1.41
    3420 IDH3B ICITm + NADm -> CO2m + NADHm + AKGm 1.1.1.41
    3421 IDH3G ICITm + NADm -> CO2m + NADHm + AKGm 1.1.1.41
    4967 OGOH AKGm + NADm + COAm -> CO2m + NADHm + SUCCOAm 1.2.4.2
    1743 DLST, DLTS AKGm + NADm + COAm -> CO2m + NADHm + SUCCOAm 2.3.1.61
    8802 SUCLG1, SUCLA1 GTPm + SUCCm + COAm <-> GDPm + Plm + SUCCOAm 6.2.1.4
    8803 SUCLA2 ATPm + SUCCm + COAm <-> ADPm + Plm + SUCCOAm 6.2.1.4
    2271 FH FUMm + H2Om <-> MALm 4.2.1.2
    4190 MDH1 MAL + NAD <-> NADH + OA 1.1.1.37
    4191 MDH2 MALm + NADm <-> NADHm + OAm 1.1.1.37
    5091 PC, PCB PYRm + ATPm + CO2m -> ADPm + OAm + Plm 6.4.1.1
    47 ACLY, ATPCL, CLATP ATP + CIT + COA + H2O -> ADP + PI + ACCOA + OA 4.1.3.8
    3657
    5105 PCK1 OA + GTP -> PEP + GDP + CO2 4.1.1.32
    5106 PCK2, PEPCK OAm + GTPm -> PEPm + GDPm + CO2m 4.1.1.32
    1.3 Pentose phosphate cycle PATH: hsa00030
    2539 G6PD, G6PD1 G6P + NADP <-> D6PGL + NADPH 1.1.1.49
    9563 H6PD 1.1.1.47
    D6PGL + H2O -> D6PGC 3.1.1.31
    25796 PGLS, 6PGL D6PGL + H2O -> D6PGC 3.1.1.31
    5226 PGD D6PGC + NADP -> NADPH + CO2 + RL5P 1.1.1.44
    6120 RPE RL5P <-> X5P 5.1.3.1
    7086 TKT R5P + X5P <-> T3P1 + S7P 2.2.1.1
    X5P + E4P <-> F6P + T3P1
    8277 TKTL1, TKR, TKT2 R5P + X5P <-> T3P1 + S7P 2.2.1.1
    X5P + E4P <-> F6P + T3P1
    6888 TALDO1 T3P1 + S7P <-> E4P + F6P 2.2.1.2
    5631 PRPS1, PRS I, PRS, I R5P + ATP <-> PRPP + AMP 2.7.6.1
    5634 PRPS2, PRS II, PRS, II R5P + ATP <-> PRPP + AMP 2.7.6.1
    2663 GDH 1.1.1.47
    1.4 Pentose and glucuronate interconversions PATH: hsa00040
    231 AKR1B1 , AR, ALDR1, ADR 1.1.1.21
    7359 UGP1 G1P + UTP -> UDPG + PPI 2.7.7.9
    7360 UGP2, UGPP2 G1P + UTP -> UDPG + PPI 2.7.7.9
    7358 UGDH, UDPGDH 1.1.1.22
    10720 UGT2B11 2.4.1.17
    54658 UGT1A1, UGT1A, GNT1, UGT1 2.4.1.17
    7361 UGT1A, UGT1, UGT1A 2.4.1.17
    7362 UGT2B, UGT2, UGT2B 2.4.1.17
    7363 UGT2B4, UGT2B11 2.4.1.17
    7364 UGT2B7, UGT2B9 2.4.1.17
    7365 UGT2B10 2.4.1.17
    7366 UGT2B15, UGT2B8 2.4.1.17
    7367 UGT2B17 2.4.1.17
    13 AADAC, DAC 3.1.1.-
    3991 LIPE, LHS, HSL 3.1.1.-
    1.5 Fructose and mannose metabolism PATH: hsa00051
    4351 MPI, PMI1 MAN6P <-> F6P 5.3.1.8
    5372 PMM1 MAN6P <-> MAN1P 5.4.2.8
    5373 PMM2, CDG1, CDGS MAN6P <-> MAN1P 5.4.2.8
    2762 GMDS 4.2.1.47
    8790 FPGT, GFPP 2.7.7.30
    5207 PFKFB1, PFRX ATP + F6P -> ADP + F26P 2.7.1.105
    F26P -> F6P + PI 3.1.3.46
    5208 PFKFB2 ATP + F6P -> ADP + F26P 2.7.1.105
    F26P -> F6P + PI 3.1.3.46
    5209 PFKF83 ATP + F6P -> ADP + F26P 2.7.1.105
    F26P -> F6P + PI 3.1.3.46
    5210 PFKFB4 ATP + F6P -> ADP + F26P 2.7.1.105
    F26P -> F6P + PI 3.1.3.46
    3795 KHK 2.7.1.3
    6652 SORD DSOT + NAD -> FRU + NADH 1.1.1.14
    2526 FUT4, FCT3A, FUC-TIV 2.4.1.-
    2529 FUT7 2.4.1.-
    3036 HAS1, HAS 2.4.1.-
    3037 HAS2 2.4.1.-
    8473 OGT, O-GLCNAC 2.4.1.-
    51144 LOC51144 1.1.1.-
    1.6 Galactose metabolism PATH: hsa00052
    2584 GALK1, GALK GLAC + ATP -> GALA P + ADP 2.7.1.6
    2585 GALK2, GK2 GLAC + ATP -> GAL1P + ADP 2.7.1.6
    2592 GALT UTP + GAL1P <-> PPI + UDPGAL 2.7.7.10
    2582 GALE UDPGAL <-> UDPG 5.1.3.2
    2720 GLB1 3.2.1.23
    3938 LCT, LAC 3.2.1.62
    3.2.1.108
    2683 B4GALT1, GGT82, BETA4GAL-71, 2.4.1.90
    GT1, GTB 2.4.1.38
    2.4.1.22
    3906 LALBA 2.4.1.22
    2717 GLA, GALA MELI -> GLC + GLAC 3.2.1.22
    2548 GAA MLT -> 2 GLC 3.2.1.20
    6DGLC -> GLAC + GLC
    2594 GANAB MLT -> 2 GLC 3.2.1.20
    6DGLC -> GLAC + GLC
    2595 GANC MLT -> 2 GLC 3.2.1.20
    6DGLC -> GLAC + GLC
    8972 MGAM, MG, MGA MLT -> 2 GLC 3.2.1.20
    6DGLC -> GLAC + GLC 3.2.1.1
    1.7 Ascorbate and aldarate metabolism PATH:hsa00053
    216 ALDH1, PUMB1 ACAL + NAD -> NADH + AC 1.2.1.3
    217 ALDH2 ACALm + NADm -> NADHm + ACm 1.2.1.3
    219 ALDH5, ALDHX 1.2.1.3
    223 ALDH9, E3 1.2.1.3
    1.2.1.19
    224 ALDH10, FALDH, SLS 1.2.1.3
    8654 RALDH2 1.2.1.3
    1591 CYP24 1.14.-.-
    1592 CYP26A1, P450RAI 1.14.-.-
    1593 CYP27A1, CTX, CYP27 1.14.-.-
    1594 CYP27B1, PDDR, VDD1, VDR, CYP1, 1.14.-.-
    VDDR, I, P450C1
    1.8 Pyruvate metabolism PATH: hsa00620
    54988 FLJ20581 ATP + AC + COA -> AMP + PPI + ACCOA 6.2.1.1
    31 ACACA, ACAC, ACC ACCOA + ATP + CO2 <-> MALCOA + ADP + PI + H 6.4.1.2
    6.3.4.14
    32 ACACB, ACCB, HACC275, ACC2 ACCOA + ATP + CO2 <-> MALCOA + ADP + PI + H 6.4.1.2
    6.3.4.14
    2739 GLO1, GLYI RGT + MTHGXL <-> LGT 4.4.1.5
    3029 HAGH, GLO2 LGT -> RGT + LAC 3.1.2.6
    2223 FDH FALD + RGT + NAD <-> FGT + NADH 1.2.1.1
    9380 GRHPR, GLXR 1.1.1.79
    4200 ME2 MALm + NADm -> CO2m + NADHm + PYRm 1.1.1.38
    10873 ME3 MALm + NADPm -> CO2m + NADPHm + PYRm 1.1.1.40
    29897 HUMNDME MAL + NADP -> CO2 + NADPH + PYR 1.1.1.40
    4199 MEI MAL + NADP -> CO2 + NADPH + PYR 1.1.1.40
    38 ACAT1, ACAT, T2, THIL, MAT 2 ACCOAm <-> COAm + AACCOAm 2.3.1.9
    39 ACAT2 2 ACCOAm <-> COAm + AACCOAm 2.3.1.9
    1.9 Glyoxylate and dicarboxylate metabolism PATH: hsa00630
    5240 PGP 3.1.3.18
    2758 GLYD 3HPm + NADHm -> NADm + GLYAm 1.1.1.29
    10797 MTHFD2, NMDMC METHF <-> FTHF 3.5.4.9
    METTHF + NAD -> METHF + NADH 1.5.1.15
    4522 MTHFD1 METTHF + NADP <-> METHF + NADPH 1.5.1.1
    METHF <-> FTHF 3.5.4.9
    THF + FOR + ATP -> ADP + PI + FTHF 6.3.4.3
    1.10 Propanoate metabolism PATH: hsa00640
    34 ACADM, MCAD MBCOAm + FADm -> MCCOAm + FADH2m 1.3.99.3
    IBCOAm + FADm -> MACOAm + FADH2m
    IVCOAm + FADm -> MCRCOAm + FADH2m
    36 ACADSB MBCOAm + FADm -> MCCOAm + FADH2m 1.3.99.3
    IBCOAm + FADm -> MACOAm + FADH2m
    IVCOAm + FADm -> MCRCOAm + FADH2m
    1892 ECHS1, SCEH MACOAm + H2Om -> HIBCOAm 4.2.1.17
    MCCOAm + H2Om -> MHVCOAm
    1962 EHHADH MHVCOAm + NADm -> MAACOAm + NADHm 1.1.1.35
    HIBm + NADm -> MMAm + NADHm
    MACOAm + H2Om -> HIBCOArn 4.2.1.17
    MCCOAm + H2Om -> MHVCOAm
    3030 HADHA, MTPA, GBP MHVCOAm + NADm -> MAACOAm + NADHm 1.1.1.35
    HIBm + NADm -> MMAm + NADHm
    MACOAm + H2Om -> HIBCOAm 4.2.1.17
    MCCOAm + H2Om -> MHVCOAm
    C160CARm + COAm + FADm + NADm -> FADH2m + NADHm + 1.1.1.35
    C140COAm + ACCOAm 4.2.1.17
    23417 MLYCD, MCD 4.1.1.9
    18 ABAT, GABAT GABA + AKG -> SUCCSAL + GLU 2.6.1.19
    5095 PCCA PROPCOAm + CO2m + ATPm -> ADPm + Plm + DMMCOAm 6.4.1.3
    5096 PCCB PROPCOAm + CO2m + ATPm -> ADPm + Pim + DMMCOAm 6.4.1.3
    4594 MUT, MCM LMMCOAm -> SUCCOAm 5.4.99.2
    4329 MMSDH MMAm + COAm + NADm -> NADHm + CO2m + PROPCOAm 1.2.1.27
    8523 FACVL1, VLCS, VLACS 6.2.1.-
    1.11 Butanoate metabolism PATH:hsa00650
    3028 HADH2, ERAS C140COAm + 7 COAm + 7 FADm + 7 NADm -> 7 FADH2m + 7 1.1.1.35
    NADHm + 7 ACCOAm
    3033 HADHSC, SCHAD 1.1.1.35
    35 ACADS, SCAD MBCOAm + FADm -> MCCOAm + FADH2m 1.3.99.2
    IBCOAm + FADm -> MACOAm + FADH2m
    7915 ALDH5A1, SSADH, SSDH 1.2.1.24
    2571 GAD1, GAD, GAD67, GAD25 GLU -> GABA + CO2 4.1.1.15
    2572 GAD2 GLU -> GABA + CO2 4.1.1.15
    2573 GADS GLU -> GABA + CO2 4.1.1.15
    3157 HMGCS1, HMGCS H3MCOA + COA <-> ACCOA + AACCOA 4.1.3.5
    3158 HMGCS2 H3MCOA + COA <-> ACCOA + AACCOA 4.1.3.5
    3155 HMGCL, HL H3MCOAm -> ACCOAm + ACTACm 4.1.3.4
    5019 OXCT 2.8.3.5
    622 BDH 3HBm + NADm -> NADHm + Hm + ACTACm 1.1.1.30
    1629 DBT, BCATE2 OMVALm + COAm + NADm -> MBCOAm + NADHm + CO2m 2.3.1.-
    OIVALm + COAm + NADm -> IBCOAm + NADHm + CO2m
    OICAPm + COAm + NADHm -> IVCOAm + NADHm + CO2m
    1.13 Inositol metabolism PATH: hsa00031
    2. Energy Metabolism
    2.1 Oxidative phosphorylation PATH: hsa00190
    4535 MTND1 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    4636 MTND2 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    4537 MTND3 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    4538 MTND4 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    4539 MTND4L NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    4240 MINDS NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    4541 MTND8 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    4694 NDUFA1, MWFE NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    4695 NDUFA2, B8 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4696 NDUFA3, B9 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4697 NDUFA4, MLRQ NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4698 NDUFA5, UQOR13, 813 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4700 NOUFA6, B14 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4701 NOUFA7, B14.5a, B14.5A NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4702 NDUFA8, PGIV NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1,6.99.3
    4704 NDUFA9, NDUFS2L NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4705 NDUFA10 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4706 NDUFAB1, SDAP NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4707 NDUFB1, MNLL, CI-SGDH NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4708 NDUFB2, AGGG NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4709 NDUFB3, B12 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4710 NOUFB4, B15 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4711 NDUFB5, SGDH NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4712 NDUF86, B17 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4713 NDUFB7, B18 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4714 NDUFBB, ASHI NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4715 NDUFB9, UQOR22, B22 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4716 NDUFB10, PDSW NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4717 NDUFCI, KFYI NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4718 NDUFC2, B14.5b, B14.58 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4724 NDUFS4, AQDQ NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4725 NDUFS5 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4726 NDUFS6 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4731 NDUFV3 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    4127 NDUFS7, PSST NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4722 NDUFS3 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.1
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4720 NDUFS2 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    4729 NDUFV2 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4723 NDUFV1, UPOR1 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    4719 NDUFS1, PRO1304 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    4728 NDUFS8 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.5.3
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 1.6.99.3
    6391 SDHC SUCCm + FADm <-> FUMm + FADH2m 1.3.5.1
    FADH2m + Qm <-> FADm + QH2m
    6392 SDHD, CBT1, PGL, PGL1 SUCCm + FADm <-> FUMm + FADH2m 1.3.5.1
    FADH2m + Qm <-> FADm + QH2m
    6389 SDHA, SDH2, SDHF, FP SUCCm + FADm <-> FUMm + FADH2m 1.3.5.1
    FADH2m + Qm <-> FADm + QH2m
    6390 SDHB, SDH1, IP, SDH SUCCm + FADm <-> FUMm + FADH2m 1.3.5.1
    FADH2m + Qm <-> FADm + QH2m
    7386 UQCRFS1, RIS1 O2m + 4 FEROm + 4 Hm -> 4 FERIm + 2 H2Om + 4 H 1.10.2.2
    4519 MTCYB O2m + 4 FEROm + 4 Hm -> 4 FERIm + 2 H2Om + 4 H 1.10.2.2
    1537 CYC1 O2m + 4 FEROm + 4 Hm -> 4 FERIm + 2 H2Om + 4 H 1.10.2.2
    7384 UQCRCI, D3S3191 O2m + 4 FEROm + 4 Hm -> 4 FERIm + 2 H2Om + 4 H 1.10.2.2
    7385 UQCRC2 O2m + 4 FEROm + 4 Hm -> 4 FERIm + 2 H2Om + 4 H 1.10.2.2
    7388 UQCRH O2m + 4 FEROm + 4 Hm -> 4 FERIm + 2 H2Om + 4 H 1.10.2.2
    7381 UQCRB, QPC, UQBP, QP-C O2m + 4 FEROm + 4 Hm -> 4 FERIm + 2 H2Om + 4 H 1.10.2.2
    27089 QP-C O2m + 4 FEROm + 4 Hm -> 4 FERIm + 2 H2Om + 4 H 1.10.2.2
    10975 UQCR O2m + 4 FEROm + 4 Hm -> 4 FERIm + 2 H2Om + 4 H 1.10.2.2
    1333 COX5BL4 QH2m + 2 FERIm + 4 Hm -> Qm + 2 FEROm + 4 H 1.9.3.1
    4514 MTCO3 QH2m + 2 FERIm + 4 Hm -> Qm + 2 FEROm + 4 H 1.9.3.1
    4512 MTCO1 QH2m + 2 FERIm + 4 Hm -> Qm + 2 FEROm + 4 H 1.9.3.1
    4513 MTCO2 QH2m + 2 FERIm + 4 Hm -> Qm + 2 FEROm + 4 H 1.9.3.1
    1329 COX5B QH2m + 2 FERIm + 4 Hm -> Qm + 2 FEROm + 4 H 1.9.3.1
    1327 COX4 QH2m + 2 FERIm + 4 Hm -> Om + 2 FEROm + 4 H 1.9.3.1
    1337 COX6A1, COX6A QH2m + 2 FERIm + 4 Hm -> Qm + 2 FEROm + 4 H 1.9.3.1
    1339 COX6A2 QH2m + 2 FERIm + 4 Hm -> Qm + 2 FEROm + 4 H 1.9.3.1
    1340 COX6B QH2m + 2 FERIm + 4 Hm -> Qm + 2 FEROm + 4 H 1.9.3.1
    1345 COX6C QH2m + 2 FERIm + 4 Hm -> Qm + 2 FEROm + 4 H 1.9.3.1
    9377 COX5A, COX, VA, COX-VA QH2m + 2 FERIm + 4 Hm -> Qm + 2 FEROm + 4 H 1.9.3.1
    1346 COX7A1, COX7AM, COX7A QH2m + 2 FERIm + 4 Hm -> Qm + 2 FEROm + 4 H 1.9.3.1
    1347 COX7A2, COX VIIa-L QH2m + 2 FERIm + 4 Hm -> Om + 2 FEROm + 4 H 1.9.3.1
    1346 COX7A3 QH2m + 2 FERIm + 4 Hm -> Gm + 2 FEROm + 4 H 1.9.3.1
    1349 COX7B QH2m + 2 FERIm + 4 Hm -> Gm + 2 FEROm + 4 H 1.9.3.1
    9167 COX7A2L, COX7RP, EB1 QH2m + 2 FERIm + 4 Hm -> Qm + 2 FEROm + 4 H 1.9.3.1
    1350 COX7C QH2m + 2 FERIm + 4 Hm -> Qm + 2 FEROm + 4 H 1.9.3.1
    1351 COX8, COX VIII QH2m + 2 FERIm + 4 Hm -> Qm + 2 FEROm + 4 H 1.9.3.1
    4508 MTATP6 ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    4509 MTATP8 ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    499 ATP5A2 ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    507 ATP5BL1, ATPSBL1 ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    508 ATP5BL2, ATPSBL2 ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    519 ATP5H ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    537 ATP6S1, ORF, VATPS1, XAP-3 ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    514 ATP5E ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    513 ATP5D ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    506 ATP5B, ATPSB ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    509 ATP5C1, ATP5C ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    498 ATP5A1, ATP5A, ATPM, OMR, HATP1 ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    539 ATP5O, ATPO, OSCP ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    516 ATP5G1, ATP5G ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    517 ATP5G2 ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    518 ATP5G3 ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    515 ATP5F1 ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    521 ATP5I ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    522 ATP5J, ATP5A, ATPM, ATP5 ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    9551 ATP5J2, ATP5JL, F1FO-ATPASE ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    10476 ATP5JD ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    10632 ATP5JG ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    9296 ATP6S14 ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    528 ATP6D ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    523 ATP6A1, VPP2 ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    524 ATP6A2, VPP2 ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    525 ATP681, VPP3, VATB ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    526 ATP682, VPP3 ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    529 ATP6E ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    527 ATP8C, ATPL ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    533 ATP6F ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    10312 TCIRG1, TIRC7, OC-116, 0C-116kDa, ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    OC-116KDA, ATP6N1C
    23545 TJ6 ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    50617 ATP6N1B ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    535 ATP6N1 ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    51382 VATD ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    8992 ATP6H ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    9550 ATM ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    51606 LOC51606 ADPm + Pim + 3 H -> ATPm + 3 Hm + H2Om 3.6.1.34
    495 ATP4A, ATP6A ATP + H + Kxt + H2O <-> ADP + PI + Hext + K 3.6.1.36
    476 ATP4B, ATP6B ATP + H + Kxt + H2O <-> ADP + PI + Hext + K 3.6.1.36
    477 ATP1A1 ATP + 3 NA + 2 Kxt + H2O <-> ADP + 3 NAxt + 2 K + PI 3.8.1.37
    476 ATP1A2 ATP + 3 NA + 2 Kxt + H2O <-> ADP + 3 NAxt + 2 K + PI 3.6.1.37
    478 ATPIA3 ATP + 3 NA + 2 Kxt + H2O <-> ADP + 3 NAxt + 2 K + PI 3.6.1.37
    479 ATP1AL1 ATP + 3 NA + 2 Kxt + H2O <-> ADP + 3 NAxt + 2 K + PI 3.6.1.37
    23439 ATP1B4 ATP + 3 NA + 2 Kxt + H2O <-> ADP + 3 NAxt + 2 K + PI 3.6.1.37
    481 ATP1B1, ATP1B ATP + 3 NA + 2 Kxt + H2O <-> ADP + 3 NAxt + 2 K + PI 3.6.1.37
    482 ATP1B2, AMOG ATP + 3 NA + 2 Kxt + H2O <-> ADP + 3 NAxt + 2 K + PI 3.6.1.37
    483 ATP1B3 ATP + 3 NA + 2 Kxt + H2O <-> ADP + 3 NAxt + 2 K + PI 3.6.1.37
    27032 ATP2C1, ATP2C1A, PMR1 ATP + 2 CA + H2O <-> ADP + PI + 2 CAxt 3.6.1.38
    487 ATP2A1, SERCA1, ATP2A ATP + 2 CA + H2O <-> ADP + PI + 2 CAM 3.6.1.38
    488 ATP2A2, ATP2B, SERCA2, DAR, DD ATP + 2 CA + H2O <-> ADP + PI + 2 CAxt 3.6.1.38
    489 ATP2A3, SERCA3 ATP + 2 CA + H2O <-> ADP + PI + 2 CAxt 3.6.1.38
    490 ATP2B1, PMCA1 ATP + 2 CA + H2O <-> ADP + PI + 2 CAxt 3.6.1.38
    491 ATP2B2, PMCA2 ATP + 2 CA + H2O <-> ADP + PI + 2 CAxt 3.6.1.38
    492 ATP2B3, PMCA3 ATP + 2 CA + H2O <-> ADP + PI + 2 CAxt 3.6.1.38
    493 ATP2B4, ATP2B2, PMCA4 ATP + 2 CA + H2O <-> ADP + PI + 2 CAxt 3.6.1.38
    538 ATP7A, MK, MNK, OHS ATP + H2O + Cu2 -> ADP + PI + Cu2xt 3.6.3.4
    540 ATP7B, WND ATP + H2O + Cu2 -> ADP + PI + Cu2xt 3.6.3.4
    5464 PP, SID6-8061 PPI -> 2 PI 3.6.1.1
    2.2 Photosynthesis PATH: hsa00195
    2.3 Carbon fixation PATH: hsa00710
    2805 GOT1 OAm + GLUm <-> ASPm + AKGm 2.6.1.1
    2806 GOT2 OA + GLU <-> ASP + AKG 2.6.1.1
    2875 GPT PYR + GLU <-> AKG + ALA 2.6.1.2
    2.4 Reductive carboxylate cycle (CO2 fixation) PATH: hsa00720
    2.5 Methane metabolism PATH: hsa00680
    847 CAT 2 H2O2 -> O2 1.11.1.6
    4025 LPO, SPO 1.11.1.7
    4353 MPO 1.11.1.7
    8288 EPX, EPX-PEN, EPO, EPP 1.11.1.7
    9588 KIAA0106, AOP2 1.11.1.7
    6470 SHMTI, CSHMT THF + SER <-> GLY + METTHF 2.1.1.1
    6472 SHMT2, GM, SHMT THFm + SERm <-> GLYm + METTHFm 2.1.2.1
    51004 LOC51004 2OPMPm + O2m -> 2OPMBm 1.14.13.-
    2OPMMBm + O2m -> 2OMHMBm
    9420 CYP7B1 2OPMPm + O2m -> 2OPMBm 1.14.13.-
    2OPMMBrn + O2m -> 2OMHM8m
    2.6 Nitrogen metabolism PATH: hsa00910
    11238 CA5B 4.2.1.1
    23632 CA14 4.2.1.1
    759 CA1 4.2.1.1
    760 CA2 4.2.1.1
    761 CA3, CAIII 4.2.1.1
    762 CA4, CAIV 4.2.1.1
    763 CA5A, CA5, CAV, CAVA 4.2.1.1
    765 CA6 4.2.1.1
    766 CA7 4.2.1.1
    767 CA8, CALS, CARP 4.2.1.1
    768 CA9, MN 4.2.1.1
    770 CA11, CARP2 4.2.1.1
    771 CA12 4.2.1.1
    1373 CPS1 GLUm + CO2m + 2 ATPm -> 2 ADPm + 2 Plm + CAPm 6.3.4.16
    275 AMT GLYm + THFm + NADm <-> METTHFm + NADHm + CO2m + 2.1.2.10
    NH3m
    3034 HAL, HSTD, HIS HIS -> NH3 + URO 4.3.1.3
    2746 GLUD1, GLUD AKGm + NADHm + NH3m <-> NADm + H2Om + GLUm 1.4.1.3
    AKGm + NADPHm + NH3m <-> NADPm + H2Om + GLUm
    8307 GLUD2 AKGm + NADHm + NH3m <-> NADm + H2Om + GLUm 1.4.1.3
    AKGm + NADPHm + NH3m <-> NADPm + H2Om + GLUm
    2752 GLUL, GLNS GLUm + NH3m + ATPm -> GLNm + ADPm + Pim 6.3.1.2
    22842 KIAA0838 GLN -> GLU + NH3 3.5.1.2
    27165 GA GLN -> GLU + NH3 3.5.1.2
    2744 GLS GLNm -> GLUm + NH3m 3.5.1.2
    440 ASNS ASPm + ATPm + GLNm -> GLUm + ASNm + AMPm + PPIm 6.3.5.4
    1491 CTH LLCT + H2O -> CYS + HSER 4.4.1.1
    OBUT + NH3 <-> HSER 4.4.1.1
    2.7 Sulfur metabolism PATH: hsa00920
    9060 PAPSS2, ATPSK2, SK2 APS + ATP -> ADP + PAPS 2.7.1.25
    SLF + ATP -> PPI + APS 2.7.7.4
    9061 PAPSS1, ATPSK1, SK1 APS + ATP -> ADP + PAPS 2.7.1.25
    SLF + ATP -> PPI + APS 2.7.1.4
    10380 BPNT1 PAP -> AMP + PI 3.1.3.7
    6799 SULT1A2 2.8.2.1
    6817 SULT1A1, STP1 2.8.2.1
    6818 SULT1A3, STM 2.8.2.1
    6822 SULT2A1, STD 2.8.2.2
    6783 STE, EST 2.8.2.4
    6821 SUOX 1.8.3.1
    3. Lipid Metabolism
    3.1 Fatty acid biosynthesis (path 1) PATH: hsa00061
    2194 FASN 2.3.1.85
    3.2 Fatty acid biosynthesis (path 2) PATH: hsa00062
    10449 ACAA2, DSAEC MAACOAm -> ACCOAm + PROPCOAm 2.3.1.16
    30 ACAA1, ACM MAACOA -> ACCOA + PROPCOA 2.3.1.16
    3032 HADHB MAACOA -> ACCOA + PROPCOA 2.3.1.16
    3.3 Fatty acid metabolism PATH: hsa00071
    51 ACOX1, ACOX 1.3.3.6
    33 ACADL, LCAD 1.3.99.13
    2639 GCDH 1.3.99.7
    2179 FACL1, LACS ATP + LCCA + COA <-> AMP + PPI + ACOA 6.2.1.3
    2180 FACL2, FACL1, LACS2 ATP + LCCA + COA <-> AMP + PPI + ACOA 6.2.1.3
    2182 FACL4, ACS4 ATP + LCCA + COA <-> AMP + PPI + ACOA 6.2.1.3
    1374 CPT1A, CPT1, CPT1-L 2.3.1.21
    1375 CPT1B, CPT1-M 2.3.1.21
    1376 CPT2, CPT1, CPTASE 2.3.121
    1632 DCI 5.3.3.8
    11283 CYP4F8 1.14.14.1
    1543 CYP1A1, CYP1 1.14.14.1
    1544 CYP1A2 1.14.14.1
    1545 CYP1B1, GLC3A 1.14.14.1
    1548 CYP2A6, CYP2A3 1.14.14.1
    1549 CYP2A7 1.14.14.1
    1551 CYP3A7 1.14.14.1
    1553 CYP2A13 1.14.14.1
    1554 CYP2B 1.14.14.1
    1555 CYP2B6 1.14.14.1
    1557 CYP2C19, CYP2C, P450IIC19 1.14.14.1
    1558 CYP2C8 1.14.14.1
    1559 CYP2C9, P450IIC9, CYP2C10 1.14.14.1
    1562 CYP2C18, P450IIC17, CYP2C17 1.14.14.1
    1565 CYP2D6 1.14.14.1
    1571 CYP2E, CYP2E1, P450C2E 1.14.14.1
    1572 CYP2F1, CYP2F 1.14.14.1
    1573 CYP2J2 1.14.14.1
    1575 CYP3A3 1.14.14.1
    1576 CYP3A4 1.14.14.1
    1577 CYP3A5, PCN3 1.14.14.1
    1580 CYP481 1.14.14.1
    1588 CYP19, ARO 1.14.14.1
    1595 CYP51 1.14.14.1
    194 AHHR, AHH 1.14.14.1
    3.4 Synthesis and degradation of ketone bodies PATH: hsa00072
    3.5 Sterol biosynthesis PATH: hsa00100
    3156 HMGCR MVL + COA + 2 NADP <-> H3MCOA + 2 NADPH 1.1.1.34
    4598 MVK, MVLK ATP + MVL -> ADP + PMVL 2.7.1.36
    CTP + MVL -> CDP + PMVL
    GTP + MVL -> GDP + PMVL
    UTP + MVL -> UDP + PMVL
    10654 PMVK, PMKASE, PMK, HUMPMKI ATP + PMVL -> ADP + PPMVL 2.7.4.2
    4597 MVD, MPD ATP + PPMVL -> ADP + PI + IPPP + CO2 4.1.1.33
    3422 IDI1 IPPP <-> DMPP 5.3.3.2
    2224 FDPS GPP + IPPP -> FPP + PPI 2.5.1.10
    DMPP + IPPP -> GPP + PPI 2.5.1.1
    9453 GGPS1, GGPPS DMPP + IPPP -> GPP + PPI 2.5.1.1
    GPP + IPPP -> FPP + PPI 2.5.1.10
    2.5.1.29
    2222 FDFT1, DGPT 2 FPP + NADPH -> NADP + SQL 2.5.1.21
    6713 SQLE SQL + O2 + NADP -> S23E + NADPH 1.14.99.7
    4047 LSS, OSC S23E -> LNST 5.4.99.7
    1728 DIA4, NMOR1, NQO1, NMORI 1.6.99.2
    4835 NMOR2, NQO2 1.6.99.2
    37 ACADVL, VLCAD, LCACD 1.3.99.-
    3.6 Bile acid biosynthesis PATH: hsa00120
    1056 CEL, BSSL, BAL 3.1.1.3
    3.1.1.13
    3988 LIPA, LAL 3.1.1.13
    6646 SOAT1, ACAT, STAT, SOAT, ACAT1,
    ACACT 2.3.1.26
    1581 CYP7A1, CYP7 1.14.13.17
    6715 SRD5A1 1.3.99.5
    6716 SRD5A2 1.3.99.5
    6718 AKR1D1, SRD5B1, 3o5bred 1.3.99.6
    570 BAAT, BAT 2.3.1.64
    3.7 C21-Steroid hormone metabolism PATH: hsa00140
    1583 CYP11A, P450SCC 1.14.15.6
    3283 HSD3B1, HSD3B, HSDB3 IMZYMST -> IIMZYMST + CO2 5.3.3.1
    IMZYMST -> IIZYMST + CO2
    1.1.1.145
    3284 HSD382 IMZYMST -> IIMZYMST + CO2 5.3.3.1
    IMZYMST -> IIZYMST + CO2
    1.1.1.145
    1589 CYP21A2, CYP21, P450C21B,
    CA21H, CYP21B, P450c218 1.14.99.10
    1586 CYP17, P450C17 1.14.99.9
    1584 CYP11B1, P450C11, CYP11B 1.14.15.4
    1585 CYP1182, CYP11B 1.14.15.4
    3290 HSD11B1, HSD11, HSD11L, HSD11B 1.1.1.146
    3291 HSD1182, HSD11K 1.1.1.146
    3.8 Androgen and estrogen metabolism PATH: hsa00150
    3292 HSD17B1, EDH17B2, EDHB17,
    HSD17 1.1.1.62
    3293 HSD17B3, EDH17B3 1.1.1.62
    3294 HSD17B2, EDH17B2 1.1.1.62
    3295 HSD17B4 1.1.1.62
    3296 HSD17BP1, EDH17B1, EDHB17,
    HSD17 1.1.1.62
    51478 HSD17B7, PRAP 1.1.1.62
    412 STS, ARSC, ARSC1, SSDD 3.1.6.2
    414 ARSD 3.1.6.1
    415 ARSE, CDPX1, CDPXR, CDPX 3.1.6.1
    11185 INMT 2.1.1.-
    24140 JM23 2.1.1.-
    29104 N6AMT1, PRED28 2.1.1.-
    299640 FJH1 2.1.1.-
    3274 HRMT1L2, HCP1, PRMT1 2.1.1.-
    51628 LOC51628 2.1.1.-
    54743 HASJ4442 2.1.1.-
    27292 HSA9761 2.1.1.-
    4. Nucleotide Metabolism
    4.1 Purine metabolism PATH: hsa00230
    11164 NUDT5, HYSAH1, YSA1H 3.6.1.13
    5471 PPAT, GPAT PRPP + GLN -> PPI + GLU + PRAM 2.4.2.14
    2614 GART, PGFT, PRGS PRAM + ATP + GLY <-> ADP + PI + GAR 6.3.4.13
    FGAM + ATP -> ADP + PI + AIR 6.3.3.1
    GAR + FTHF -> THF + FGAR 2.1.2.2
    5198 PFAS, FGARAT, KIAA0361, PURL FGAR + ATP + GLN -> GLU + ADP + PI + FGAM 6.3.5.3
    10606 ADE2H1 CAIR + ATP + ASP <-> ADP + PI + SAICAR 6.3.2.6
    CAIR <-> AIR + CO2 4.1.1.21
    5059 PAICS, AIRC, PAIS CAIR + ATP + ASP <-> ADP + PI + SAICAR 8.3.2.6
    158 ADSL ASUC <-> FUM + AMP 4.3.2.2
    471 ATIC, PURH AICAR + FTHF <-> THF + PRFICA 2.1.2.3
    PRFICA <-> IMP 3.5.4.10
    3251 HPRT1, HPRT, HGPRT HYXAN + PRPP -> PPI + IMP 2.4.2.8
    GN + PRPP -> PPI + GMP
    3614 IMPDH1 IMP + NAD -> NAOH + XMP 1.1.1.205
    3615 IMPDH2 IMP + NAD -> NAOH + XMP 1.1.1.205
    8833 GMPS 6.3.5.2
    14923
    2987 GUK1 GMP + ATP <-> GDP + ADP 2.7.4.8
    DGMP + ATP <-> DGDP + ADP
    GMP + OATP <-> GDP + DADP
    2988 GUK2 GMP + ATP <-> GDP + ADP 2.7.4.8
    DGMP + ATP <-> DGDP + ADP
    GMP + DATP <-> GOP + DADP
    10621 RPC39 2.7.7.6
    10622 RPC32 2.7.7.6
    10623 RPC62 2.7.7.6
    11128 RPC155 2.7.7.6
    25885 DKFZP586M0122 2.7.7.6
    30834 2NRD1 2.7.7.6
    51082 LOC51082 2.7.7.6
    51728 LOC51728 2.7.7.6
    5430 POLR2A, RPOL2, POLR2, POLRA 2.7.7.6
    5431 POLR2B, POL2RB 2.7.7.6
    5432 POLR2C 2.7.7.6
    5433 POLR2D, HSRBP4, HSRPB4 2.7.7.6
    5434 POLR2E, RPB5, XAP4 2.7.7.6
    5435 POLR2F, RPB6, HRBP14.4 2.7.7.6
    5436 POLR2G, RPB7 2.7.7.6
    5437 POLR2H, RPB8, RPB17 2.7.7.6
    5438 POLR2I 2.7.7.6
    5439 POLR2J 2.7.7.6
    5440 POLR2K, RP87.0 2.7.7.6
    5441 POLR2L, RPB7.6, RPB10 2.7.7.6
    5442 POLRMT, APOLMT 2.7.7.6
    54479 FLJ10816, Rpo1-2 2.7.7.6
    55703 FLJ10388 2.7.7.6
    661 BN51T 2.7.7.6
    9533 RPA40, RPA39 2.7.7.6
    10721 POLQ 2.7.7.7
    11232 POLG2, MTPOLB, HP55, POLB 2.7.7.7
    23649 POLR2 2.7.7.7
    5422 POLA 2.7.7.7
    5423 POLB 2.7.7.7
    5424 POLD1, POLD 2.7.7.7
    5425 POLD2 2.7.7.7
    5426 POLE 2.7.7.7
    5427 POLE2 2.7.7.7
    5428 POLG 2.7.7.7
    5980 REV3L, POLZ, REV3 2.7.7.7
    7498 XDH 1.1.3.22
    1.1.1.204
    9615 GDA, KIAA1258, CYPIN, NEDASIN 3.5.4.3
    2766 GMPR 1.6.6.8
    51292 LOC51292 1.6.6.8
    7377 UOX 1.7.3.3
    6240 RRM1 ADP + RTHIO -> DADP + OTHIO 1.17.4.1
    GDP + RTHIO -> DGDP + OTHIO
    COP + RTHIO -> DCDP + OTHIO
    UDP + RTHIO -> DUDP + OTHIO
    6241 RRM2 ADP + RTHIO -> DADP + OTHIO 1.17.4.1
    GDP + RTHIO -> DGDP + OTHIO
    COP + RTHIO -> DCDP + OTHIO
    UDP + RTHIO -> DUDP + OTHIO
    4860 NP, PNP AND + PI <-> AD + R1P 2.4.2.1
    GSN + PI <-> GN + R1P
    DA+ PI <-> AD+ R1P
    DG + PI <-> GN + R1P
    DIN + PI <-> HYXAN + R1P
    INS + PI <-> HYXAN + R1P
    XTSINE + PI <-> XAN + R1P
    1890 ECGF1, hPD-ECGF DU + PI <-> URA + DR1P 2.4.2.4
    DT + PI <-> THY + DR1P
    353 APRT AD + PRPP -> PPI + AMP 2.4.2.7
    132 ADK ADN + ATP -> AMP + ADP 2.7.1.20
    1633 DCK 2.7.1.74
    1716 DGUOK 2.7.1.113
    203 AK1 ATP + AMP <-> 2 ADP 2.7.4.3
    GTP + AMP <-> ADP + GDP
    ITP + AMP <-> ADP + IDP
    204 AK2 ATP + AMP <-> 2 ADP 2.7.4.3
    GTP + AMP <-> ADP + GOP
    ITP + AMP <-> ADP + IDP
    205 AK3 ATP + AMP <-> 2 ADP 2.7.4.3
    GTP + Amp <-> ADP + GOP
    ITP + AMP <-> ADP + IDP
    26289 AK5 ATP + AMP <-> 2 ADP 2.7.4.3
    GTP + AMP <-> ADP + GDP
    ITP + AMP <-> ADP + IDP
    4830 NME1, NM23, NM23-H1 UDP + ATP <-> UTP + ADP 2.7.4.6
    COP + ATP <-> CTP + ADP
    GDP + ATP <-> GTP + ADP
    IDP + ATP <-> ITP + IDP
    DGDP + ATP <-> DGTP + ADP
    DUDP + ATP <-> DUTP + ADP
    DCDP + ATP <-> DCTP + ADP
    DTDP + ATP <-> DTTP + ADP
    DADP + ATP <-> DATP + ADP
    4831 NME2, NM23-H2 UDP + ATP <-> UTP + ADP 2.7.4.6
    COP + ATP <-> CTP + ADP
    GDP + ATP <-> GTP + ADP
    DP + ATP <-> ITP + IDP
    ()GDP + ATP <-> DGTP + ADP
    DUOP + ATP <-> DUTP + ADP
    DCDP + ATP <-> DCTP + ADP
    DTDP + ATP <-> DTTP + ADP
    DADP + ATP <-> DATP + ADP
    4832 NME3, DR-nm23, DR-NM23 UDP + ATP <-> UTP + ADP 2.7.4.6
    CDP + ATP <-> CTP + ADP
    GDP + ATP <-> GTP + ADP
    IDP + ATP <-> ITP + IDP
    DGDP + ATP <-> DGTP + ADP
    DUOP + ATP <-> DUTP + ADP
    DCDP + ATP <-> DCTP + ADP
    OTDP + ATP <-> DTTP + ADP
    DADP + ATP <-> DATP + ADP
    4833 NME4 UDPm + ATPm <-> UTPm + ADPm 2.7.4.6
    CDPm + ATPm <-> CTPm + ADPm
    GDPm + ATPm <-> GTPm + ADPm
    IDPm + ATPm <-> ITPm + IDPm
    DGDPm + ATPm <-> DGTPm + ADPm
    DUDPm + ATPm <-> DUTPm + ADPm
    DCDPm + ATPm <-> DCTPm + ADPm
    DTDPm + ATPm <-> DTTPm + ADPm
    DADPm + ATPm <-> DATPm + ADPm
    22978 NT5B, PNT5, NT5B-PENDING AMP + H2O -> PI + ADN 3.1.3.5
    GMP -> PI + GSN
    CMP -> CYTD + PI
    UMP -> PI + URI
    IMP -> PI + INS
    DUMP -> DU + PI
    DTMP -> DT + PI
    DAMP -> DA + PI
    DGMP -> OG + PI
    DCMP -> DC + PI
    XMP -> PI + XTSINE
    4877 NT3 AMP -> PI + AON 3.1.3.5
    GMP -> PI + GSN
    CMP -> CYTD + P1
    UMP -> PI + URI
    IMP -> PI + INS
    DUMP -> DU + PI
    DTMP -> DT + PI
    DAMP -> DA + PI
    DGMP -> DG + PI
    DCMP -3. DC + PI
    XMP -> PI + XTSINE
    4907 NT5, CD73 AMP -> PI + ADN 3.1.3.5
    GMP -> PI + GSN
    CMP -> CYTD + PI
    UMP -> PI + URI
    IMP -> PI + INS
    DUMP -> DU + PI
    DTMP -> DT + PI
    DAMP -> DA + PI
    DGMP -> DG + PI
    DCMP -> DC + PI
    XMP -> PI + XTSINE
    7370 UMPH2 AMP -> PI + ADN 3.1.3.5
    GMP -> PI + GSN
    CMP -> CYTD + PI
    UMP -> PI + URI
    IMP -> PI + INS
    DUMP -> DU + PI
    DTMP -> DT + PI
    DAMP -> DA + PI
    DGMP -> DG + PI
    DCMP -> DC + PI
    XMP -> PI + XTSINE
    10846 PDE10A cAMP -> AMP 3.1.4.17
    cAMP -> AMP
    cdAMP -> dAMP
    cIMP -> IMP
    cGMP -> GMP
    cCMP -> CMP
    27115 PDE713 cAMP -> AMP 3.1.4.17
    cAMP -> AMP
    cdAMP -> dAMP
    cIMP -> IMP
    cGMP -> GMP
    cCMP -> CMP
    5136 PDE1A cAMP -> AMP 3.1.4.17
    cAMP -> AMP
    cdAMP -> dAMP
    cIMP -> IMP
    cGMP -> GMP
    cCMP -> CMP
    5137 PDE1C, HCAM3 cAMP -> AMP 3.1.4.17
    cAMP -> AMP
    cdAMP -> dAMP
    cIMP -> IMP
    cGMP -> GMP
    cCMP -> CMP
    5138 PDE2A cAMP -> AMP 3.1.4.17
    cAMP -> AMP
    cdAMP -> dAMP
    cIMP -> IMP
    cGMP -> GMP
    cCMP -> CMP
    5139 PDE3A, CGI-PDE cAMP -> AMP 3.1.4.17
    cAMP -> AMP
    cdAMP -> dAMP
    cIMP -> IMP
    cGMP -> GMP
    cCMP -> CMP
    5140 PDE3B cAMP -> AMP 3.1.4.17
    cAMP -> AMP
    cdAMP -> dAMP
    cIMP -> IMP
    cGMP -> GMP
    cCMP -> CMP
    5141 PDE4A, DPDE2 cAMP -> AMP 3.1.4.17
    5142 PDE4B, DPDE4, PDEIVB cAMP -> AMP 3.1.4.17
    5143 PDE4C, DPDE1 cAMP -> AMP 3.1.4.17
    5144 PDE4D, DPDE3 cAMP -> AMP 3.1.4.17
    5145 PDE6A, PDEA, CGPR-A cGMP -> GMP 3.1.4.17
    5146 PDE6C, PDEA2 cGMP -> GMP 3.1.4.17
    5147 PDE6D cGMP -> GMP 3.1.4.17
    5148 PDE6G, PDEG cGMP -> GMP 3.1.4.17
    5149 PDE6H cGMP -> GMP 3.1.4.17
    5152 PDE9A cAMP -> AMP 3.1.4.17
    cAMP -> AMP
    cdAMP -> dAMP
    cIMP -> IMP
    cGMP -> GMP
    cCMP -> CMP
    5153 PDES1B cAMP -> AMP 3.1.4.17
    cAMP -> AMP
    cdAMP -> dAMP
    cIMP -> IMP
    cGMP -> GMP
    cCMP -> CMP
    5158 PDE6B, CSN83, PDEB cGMP -> GMP 3.1.4.17
    8654 PDE5A cGMP -> GMP 3.1.4.17
    100 ADA ADN -> INS + NH3 3.5.4.4
    DA -> DIN + NH3
    270 AMPD1, MADA AMP -> IMP + NH3 3.5.4.6
    271 AMPD2 AMP -> IMP + NH3 3.5.4.6
    272 AMPD3 AMP -> IMP + NH3 3.5.4.6
    953 ENTPD1, CD39 3.6.1.5
    3704 ITPA 3.6.1.19
    107 ADCY1 ATP -> cAMP + PPI 4.6.1.1
    108 ADCY2, HBAC2 ATP -> cAMP + PPI 4.6.1.1
    109 ADCY3, AC3, KIAA0511 ATP -> cAMP + ppl 4.6.1.1
    110 ADCY4 ATP -> cAMP + PPI 4.6.1.1
    111 ADCY5 ATP -> cAMP + pp! 4.6.1.1
    112 ADCY6 ATP -> CAMP + PPI 4.6.1.1
    113 ADCY7, KIAA0037 ATP -> cAMP + PPI 4.6.1.1
    114 ADCY8, ADCY3, HBAC1 ATP -> cAMP + PPI 4.6.1.1
    115 ADCY9 ATP -> cAMP + PPI 4.6.1.1
    2977 GUCY1A2, GUC1A2, GC-SA2 4.6.1.2
    2982 GUCY1A3, GUC1A3, GUCSA3, GC- 4.6.1.2
    SA3
    2983 GUCY1B3, GUC1B3, GUCSB3, GC- 4.6.1.2
    SBC
    2984 GUCY2C, GUC2C, STAR 4.6.1.2
    2986 GUCY2F, GUC2F, GC-F, GUC2DL, 4.6.1.2
    RETGC-2
    3000 GUCY2D, CORD6, GUC2D, LCA1, 4.6.1.2
    GUC1A4, LCA, retGC
    4881 NPR1, ANPRA, GUC2A, NPRA 4.6.12
    4882 NPR2, ANPRB, GUC28, NPRB,
    NPRBi 4.6.1.2
    159 ADSS IMP + GTP + ASP -> GDP + PI + ASUC 6.3.4.4
    318 NUDT2, APAH1 3.6.1.17
    5167 ENPP1, M6S1, LAPPS, PCA1, PC-1, 3.6.1.9
    PDNP1
    5168 ENPP2, ATX, PD-IALPHA, PDNP2 3.6.1.9
    5169 ENPP3, PD-IBETA, PDNP3 3.6.1.9
    3.1.4.1
    2272 FHIT 3.6.1.29
    4.2 Pyrimidine metabolism PATH: hsa00240
    790 CAD GLN + 2 ATP + CO2 -> GLU + CAP + 2 ADP + PI 6.3.5.5
    CAP + ASP -> CAASP + PI 2.1.3.2
    CAASP <-> DOROA 3.5.2.3
    1723 DHODH DOROA + O2 <-> H2O2 + OROA 1.3.3.1
    7372 UMPS, OPRT OMP -> CO2 + UMP 4.1.1.23
    OROA + PRPP <-> PPI + OMP 2.4.2.10
    51727 LOC51727 ATP + UMP <-> ADP + UDP 2.7.4.14
    CMP + ATP <-> ADP + COP
    DCMP + ATP <-> ADP + DCDP
    50808 AKL3L 2.7.4.10
    1503 CTPS UTP + GLN + ATP -> GLU + CTP + ADP + PI 6.3.4.2
    ATP + UTP + NH3 -> ADP + PI + CTP
    7371 UMPK, TSA903 URI + ATP -> ADP + UMP 2.7.1.48
    URI + GTP -> UMP + GDP
    CYTD + GTP -> GDP + CMP
    7378 UP URI + PI <-> URA + R1P 2.4.2.3
    1806 DPYD, DPD 1.3.1.2
    1807 DPYS, DHPase, DHPASE, DHP 3.5.2.2
    51733 LOC51733 3.5.1.6
    7296 TXNRD1, TXNR OTHIO + NADPH -> NADP + RTHIO 1.6.4.5
    1854 DUT DUTP -> PPI + DUMP 3.6.1.23
    7298 TYMS, TMS, TS DUMP + METTHF -> DHF + DTMP 2.1.1.45
    978 CDA, CDD CYTD -> URI + NH3 3.5.4.5
    DC -> NH3 + DU
    1635 DCTD DCMP <-> DUMP + NH3 3.5.4.12
    7083 TK1 DU + ATP -> DUMP + ADP 2.7.1.21
    DT + ATP -> ADP + DTMP
    7084 TK2 DUm + ATPm -> DUMPm + ADPm 2.7.1.21
    DTm + ATPm -> ADPm + DTMPm
    1841 DTYMK, TYMK, CDC8 DTMP + ATP <-> ADP + DTDP 2.7.4.9
    4.3 Nucleotide sugars metabolism PATH: hsa00520
    23483 TDPGD 4.2.1.46
    1486 CTBS, CTB 3.2.1.-
    5. Amino Acid Metabolism
    5.1 Glutamate metabolism PATH: hsa00251
    8659 ALDH4, P5CDH P5C + NAD + H2O -> NADH + GLU 1.5.1.12
    2058 EPRS, QARS, QPRS GLU + ATP -> GTRNA + AMP + PPI 6.1.1.17
    6.1.1.15
    2673 GFPT1, GFA, GFAT, GFPT F6P + GIN -> GLU + GA6P 2.6.1.16
    9945 GFPT2, GFAT2 F6P + GLN -> GLU + GA6P 2.6.1.16
    5859 QARS 6.1.1.18
    2729 GLCLC, GCS, GLCL CYS + GLU + ATP -> GC + PI + ADP 6.3.2.2
    2730 GLCLR CYS + GLU + ATP -> GC + PI + ADP 6.3.2.2
    2937 GSS, GSHS GLY + GC + ATP -> RGT + PI + ADP 6.3.2.3
    2936 GSR NADPH + OGT -> NADP + RGT 1.6.4.2
    5188 PET112L, PET112 6.3.5.-
    5.2 Alanine and aspartate metabolism PATH: hsa00252
    4677 NARS, ASNRS ATP + ASP + TRNA -> AMP + PPI + ASPTRNA 6.1.1.22
    435 ASL ARGSUCC -> FUM + ARG 4.12.1
    189 AGXT, SPAT SERm + PYRm <-> ALAm + 3HPm 2.6.1.51
    ALA + GLX <-> PYR + GLY 2.6.1.44
    16 AARS 6.1.1.7
    1615 DARS 6.1.1.12
    445 ASS, CTLN1, ASS1 CITR + ASP + ATP <-> AMP + PPI + ARGSUCC 6.3.4.5
    443 ASPA, ASP, ACY2 3.5.1.15
    1384 CRAT, CAT1 2.3.1.7
    ACCOA + CAR -> COA + ACAR
    8528 DDO 1.4.3.1
    5.3 Glycine, serine and threonine metabolism PATH: hsa00260
    5723 PSPH, PSP 3PSER + H2O -> PI + SER 3.1.3.3
    29968 PSA PHP + GLU <-> AKG + 3PSER 2.6.1.52
    OHB + GLU <-> PHT + AKG
    26227 PHGDH, SERA, PGDH, PGD, PGAD 3PG + NAD <-> NADH + PHP 1.1.1.95
    GCAT, KBL 2.3.1.29
    211 ALAS1, ALAS SUCCOA + GLY -> ALAV + COA + CO2 2.3.1.37
    212 ALAS2, ANH1, ASB SUCCOA + GLY -> ALAV + COA + CO2 2.3.1.37
    4128 MAOA AMA + H2O + FAD -> NH3 + FADH2 + MTHGXL 1.4.3.4
    4129 MAOB AMA + H2O + FAD -> NH3 + FADH2 + MTHGXL 1.4.3.4
    26 ABP1, AOC1, DAO 1.4.3.6
    314 AOC2, DAO2, RAO 1.4.16
    8639 AOC3, VAP-1, VAP1, HPAO 1.4.3.6
    2731 GLDC GLY + LIPO <-> SAP + CO2 1.4.4.2
    1610 DAO, DAMOX 1.4.3.3
    2617 GARS 6.1.1.14
    2628 GATM 2.1.4.1
    2593 GAMT 2.1.1.2
    23761 PISD, PSSC, DKFZP566G2246, PS -> PE + CO2 4.1.1.65
    DJ858B16
    635 BHMT 2.1.1.5
    29958 DMGDH 1.5.99.2
    875 CBS SER + HCYS -> LLCT + H2O 4.2.1.22
    6301 SARS, SERS 6.1.1.11
    10993 SDS, SDH SER -> PYR + NH3 + H2O 4.2.1.13
    6897 TARS 6.1.1.3
    5.4 Methionine metabolism PATH: hsa00271
    4143 MAT1A, MATA1, SAMS1, MAT, SAMS MET + ATP + H2O -> PPI + PI + SAM 2.5.1.6
    4144 MAT2A, MATA2, SAMS2, MATII MET + ATP + H2O -> PPI + PI + SAM 2.5.1.6
    1786 DNMT1, MCMT, DNMT SAM + DNA -> SAH + DNA5MC 2.1.1.37
    10768 AHCYL1, XPVKONA SAH + H2O -> HCYS + ADN 3.3.1.1
    191 AHCY, SAHH SAH + H2O -> HCYS + ADN 3.3.1.1
    4141 MARS, METRS, MTRNS 6.1.1.10
    4548 MTR HCYS + MTHF -> THF + MET 2.1.1.13
    5.5 Cysteine metabolism PATH: hsa00272
    833 CARS 6.1.1.16
    1036 CDO1 CYS + O2 <-> CYSS 1.13.11.20
    8509 NDST2, HSST2, NST2 2.8.2.-
    5.6 Valine, leucine and isoleucine degradation PATH: hsa00280
    586 BCAT1, BCT1, ECA39, MECA39 AKG + ILE -> OMVAL + GLU 2.6.1.42
    AKG + VAL -> OIVAL + GLU
    AKG + LEU -> OICAP + GLU
    587 BCAT2, BCT2 OICAPm + GLUm <-> AKGm + LEUm 2.6.1.42
    OMVALm + GLUm <-> AKGm + ILEm
    5014 OVD1A 1.2.4.4
    593 BCKDHA, MSUD1 OMVALm + COAm + NADm -> MBCOAm + NADHm + CO2m 1.2.4.4
    OIVALm + COAm + NADm -> IBCOArn + NADHm + CO2m
    OICAPm + COAm + NADm -> IVCOAm + NADHm + CO2m
    594 BCKDHB, E1B OMVALm + COAm + NADm -> MBCOAm + NADHm + CO2m 1.2.4.4
    OIVALm + COAm + NADm -> IBCOAm + NADHm + CO2m
    OICAPm + COAm + NADH -> IVCOAm + NADHm + CO2m
    3712 IVD IVCOAm + FADm -> MCRCOAm + FADH2m 1.3.99.10
    316 AOX1, AO 1.2.3.1
    4164 MCCC1 MCRCOAm + ATPm + CO2m + H2Om -> MGCOAm + ADPm + 6.4.1.4
    Pim
    4165 MCCC2 MCRCOAm + ATPm + CO2m + H2Om -> MGCOAm + ADPm + 6.4.1.4
    Pim
    5.7 Valine, leucine and Isoleucine biosynthesis PATH: hsa00290
    23395 KIAA0028, LARS2 6.4.1.4
    3926 LARS 6.4.1.4
    3376 IARS, ILRS 6.1.1.5
    7406 VARS1, VARS 6.1.1.9
    7407 VARS2, G7A 6.1.1.9
    5.8 Lysine biosynthesis PATH: ttsa00300
    3735 KARS, KIAA0070 ATP + LYS + LTRNA -> AMP + PPI + LLTRNA 6.1.1.6
    5.9 Lysine degradation PATH: hsa00310
    8424 BBOX, BBH, GAMMA-BBH, G-BBH 1.14.11.1
    5351 PLOD, LLH 1.14.11.4
    5352 PLOD2 1.14.11.4
    8985 PLOD3, 1H3 1.14.11.4
    10157 LKR/SDH, AASS LYS + NADPH + AKG -> NADP + H2O + SAC 1.5.1.9
    SAC + H2O + NAD -> GLU + NADH + AASA
    5.10 Arginine and praline metabolism PATH: hsa00330
    5009 OTC ORNm + CAPm -> CITRm + Pim + Hm 2.1.3.3
    383 ARG1 ARG -> ORN + UREA 3.5.3.1
    384 ARG2 ARG -> ORN + UREA 3.5.3.1
    4842 NOS1, NOS 1.14.13.39
    4843 NOS2A, NOS2 1.14.13.39
    4846 NOS3, ECHOS 1.14.13.38
    4942 OAT ORN + AKG <-> GLUGSAL + GLU 2.8.1.13
    5831 PYCRI, P5C, PYCR P5C + NADPH -> PRO + NADP 1.5.1.2
    P5C + NADH -> PRO + NAD
    PHC + NADPH -> HPRO + NADP
    PHC + NADH -> HPRO + NAD
    5033 P4HA1, P4HA 1.14.11.2
    5917 RARS ATP + ARG + ATRNA -> AMP + PPI + ALTRNA 6.1.1.19
    1152 CKB, CKBB PCRE + ADP -> CRE + ATP 2.7.3.2
    1156 CKBE 2.7.3.2
    1158 CKM, CKMM 2.7.3.2
    1159 CKMT1, CKMT, UMTCK 2.7.3.2
    1160 CKMT2, SMTCK 2.7.3.2
    6723 SRM, SPS1, SRML1 PTRSC + SAM -> SPRMD + 5MTA 2.5.1.16
    262 AMD1, ADOMETDC SAM <-> DSAM + CO2 4.1.1.50
    263 AMDP1, AMD, AMD2 SAM <-> DSAM + CO2 4.1.1.50
    1725 DHPS SPRMD + Om -> DAPRP + QH2m 1.5.99.6
    6611 SMS DSAM + SPRMD -> 5MTA + SPRM 2.5.1.22
    4953 ODC1 ORN -> PTRSC + CO2 4.1.1.17
    6303 SAT, SSAT 2.3.1.57
    5.11 Histidine metabolism PATH: hsa00340
    10841 FTCD FIGLU + THF -> NFTHF + GLU 2.1.2.5
    4.3.1.4
    3067 HDC 4.1.1.22
    1644 DDC, AADC 4.1.1.28
    3176 HNMT 2.1.1.8
    218 ALDH3 ACAL + NAD -> NADH + AC 1.2.1.5
    220 ALDH6 ACAL + NAD -> NADH + AC 1.2.1.5
    221 ALDH7, ALDH4 ACAL + NAD -> NADH + AC 1.2.1.5
    222 ALDH8 ACAL + NAD -> NADH + AC 1.2.1.5
    3035 HARS ATP + HIS + HTRNA -> AMP + PPI + HHTRNA 6.1.1.21
    5.12 Tyrosine metabolism PATH: hsa00350
    6898 TAT AKG + TYR -> HPHPYR + GLU 2.6.1.5
    3242 HPD, PPD HPHPYR + O2 -> HGTS + CO2 1.13.11.27
    3081 HGD, AKU, HGO HGTS + O2 -> MACA 1.13.11.5
    2954 GSTZI, MAAI MACA -> FACA 5.2.1.2
    2.5.1.14
    2184 FAH FACA + H2O -> FUM + ACA 3.7.1.2
    7299 TYR, OCAIA 1.14.18.1
    7054 TH, TYH 1.14.16.2
    1621 DBH 1.14.17.1
    5409 PNMT, PENT 2.1.1.28
    1312 COMT 2.1.1.6
    7173 TPO, TPX 1.11.1.8
    5.13 Phenylalanine metabolism PATH: hsa00360
    501 ATQ1 1.2.1.-
    5.14 Tryptophan metabolism PATH: hsa00380
    6999 TDO2, TPH2, TRPO, TDO TRP + O2 -> FKYN 1.13.11.11
    8564 KMO KYN + NADPH + O2 -> HKYN + NADP + H2O 1.14.13.9
    8942 KYNU KYN -> ALA + AN 3.7.1.3
    HKYN + H2O -> HAN + ALA
    23498 HMO, HAO, 3-HAO HAN + O2 -> CMUSA 1.13.11.6
    7166 TPH, TPRH 1.14.16.4
    438 ASMT, HIOMT, ASMTY 2.1.1.4
    15 AANAT, SNAT 2.3.1.87
    3620 INDO, IDO 1.13.11.42
    10352 WARS2 ATPm + TRPm + TRNAm -> AMPm + PPIm + TRPTRNAm 6.1.1.2
    7453 WARS, IFP53, IF153, GAMMA-2 ATP + TRP + TRNA -> AMP + PPI + TRPTRNA 6.1.1.2
    4734 NEDD4, KIAA0093 6.3.2.-
    5.15 Phenylalanine, tyrosine and tryptophan biosynthesis PATH: hsa00400
    5053 PAH, PKU1 PHE + THBP + O2 -> TYR + DHBP + H2O 1.14.16.1
    10667 FARS1 6.1.1.20
    2193 FARSL, CML33 6.1.1.20
    10056 PheHB 6.1.1.20
    8565 YARS, TYRRS, YTS, YRS 6.1.1.1
    5.16 Urea cycle and metabolism of amino groups PATH: hsa00220
    5832 PYCS 2.7.2.11
    GLUP + NADH -> NAD + PI + GLUGSAL 1.2.1.41
    GLUP + NADPH -> NADP + PI + GLUGSAL
    95 ACY1 3.5.1.14
    6. Metabolism of Other Amino Acids
    6.1 beta-Alanine metabolism PATH: hsa00410
    6.2 Taurine and hypotaurine metabolism PATH: hsa00430
    2678 GGT1, GTG, D22S672, D22S732, RGT + ALA -> CGLY + ALAGLY 2.3.2.2
    GGT
    2679 GGT2, GGT RGT + ALA -> CGLY + ALAGLY 2.3.2.2
    2680 GGT3 RGT + ALA -> CGLY + ALAGLY 2.3.2.2
    2687 GGTLA1, GGT-REL, DKFZP566O011 RGT + ALA -> CGLY + ALAGLY 2.3.2.2
    6.3 Aminophosphonate metabolism PATH: hsa00440
    5130 PCYT1A, CTPCT, CT, PCYT1 PCHO + CTP -> CDPCHO + PPI 2.7.7.15
    9791 PTDSS1, KIAA0024, PSSA CDPDG + SER <-> CMP + PS 2.7.8.-
    6.4 Selenoamino acid metabolism PATH: hsa00450
    22928 SPS2 2.7.9.3
    22929 SPS, SELD 2.7.9.3
    6.5 Cyanoamino acid metabolism PATH: hsa00460
    6.6 D-Glutamine and D-glutamate metabolism PATH: hsa00471
    6.7 D-Arginine and D-ornithine metabolism PATH: hsa00472
    6.9 Glutathione metabolism PATH: hsa00480
    5182 PEPB 3.4.11.4
    2655 GCTG 2.3.2.4
    2876 GPX1, GSHPX1 2 RGT + H2O2 <-> OGT 1.11.1.9
    2877 GPX2, GSHPX-GI 2 RGT + H2O2 <-> OGT 1.11.1.9
    2878 GPX3 2 RGT + H2O2 <-> OGT 1.11.1.9
    2879 GPX4 2 RGT + H2O2 <-> OGT 1.11.1.9
    2880 GPX5 2 RGT + H2O2 <-> OGT 1.11.1.9
    2881 GPX6 2 RGT + H2O2 <-> OGT 1.11.1.9
    2938 GSTA1 2.5.1.18
    2939 GSTA2, GST2 2.5.1.18
    2940 GSTA3 2.5.1.18
    2941 GSTA4 2.5.1.18
    2944 GSTM1, GST1, MU 2.5.1.18
    2946 GSTM2, GST4 2.5.1.18
    2947 GSTM3, GST5 2.5.1.18
    2948 GSTM4 2.5.1.18
    2949 GSTM5 2.5.1.18
    2950 GSTP1, FAEES3, DFN7, GST3, PI 2.5.1.18
    2952 GSTT1 2.5.1.18
    2953 GSTT2 2.5.1.18
    4257 MGST1, GST12, MGST, MGST-I 2.5.1.18
    4258 MGST2, GST2, MGST-II 2.5.1.18
    4259 MGST3, GST-III 2.5.1.18
    7. Metabolism of Complex Carbohydrates
    7.1 Starch and sucrose metabolism PATH: hsa00500
    6476 SI 3.2.1.10
    3.2.1.48
    11181 TREH, TRE, TREA TRE -> 2 GLC 3.2.1.28
    2990 GUSB 3.2.1.31
    2632 GBE1 GLYCOGEN + PI -> G1 P 2.4.1.18
    5834 PYGB GLYCOGEN + PI -> G1P 2.4.1.1
    5836 PYGL GLYCOGEN + PI -> G1P 2.4.1.1
    5837 PYGM GLYCOGEN + PI -> G1P 2.4.1.1
    2997 GYS1, GYS UDPG -> UDP + GLYCOGEN 2.4.1.11
    2998 GYS2 UDPG -> UDP + GLYCOGEN 2.4.1.11
    276 AMY1A, AMY1 3.2.1.1
    277 AMY1B, AMY1 3.2.1.1
    278 AMY1C, AMY1 3.2.1.1
    279 AMY2A, AMY2 3.2.1.1
    280 AMY2B, AMY2 3.2.1.1
    178 AGL, GDE 2.4.1.25
    3.2.1.33
    10000 AKT3, PKBG, RAC-GAMMA, PRKBG 2.7.1.-
    1017 CDK2
    1018 CDK3 2.7.1.-
    1019 CDK4, PSK-J3 2.7.1.-
    1020 CDK5, PSSALRE 2.7.1.-
    1021 CDK8, PLSTIRE 2.7.1.-
    1027 CDK7, CAK1, STK1, CDKN7 2.7.1.-
    1024 CDK8, K35 2.7.1.-
    1025 CDK9, PITALRE, CDC2L4 2.7.1.-
    10298 PAK4 2.7.1.-
    10748 MAP3K2, MEKK2 2.7.1.-
    1111 CHEK1, CHK1 2.7.1.-
    11200 RAD53, CHK2, CDS1, HUCDS1 2.7.1.-
    1195 CLK1, CLK 2.7.1.-
    1326 MAP3K8, COT, EST, ESTF, TPL-2 2.7.1.-
    1432 MAPK14, CSBP2, CSPB1, PRKM14,
    PRKM15, CSBP1, P38, MXI2 2.7.1.-
    1452 CSNK1A1 2.7.1.-
    1453 CSNK1D, HCKID 2.7.1.-
    1454 CSNK1E, HCKIE 2.7.1.-
    1455 CSNK1G2 2.7.1.-
    1456 CSNK1G3 2.7.1.-
    1612 DAPK1, DAPK 2.7.1.-
    1760 DMPK, DM, DMK, DM1 2.7.1.-
    1859 DYRKIA, DYRK1, DYRK, MNB, MNBH 2.7.1.-
    208 AKT2, RAC-BETA, PRKBB, PKBBETA 2.7.1.-
    269 AMHR2, AMHR 2.7.1.-
    27733 RPS6KA6, RSK4 2.7.1.-
    2868 GPRK2L, GPRK4 2.7.1.-
    2869 GPRK5, GRK5 2.7.1.-
    2870 GPRK6, GRK6 2.7.1.-
    29904 HSU93850 2.7.1.-
    30811 HUNK 2.7.1.-
    3611 ILK, P59 2.7.1.-
    3654 IRAK1, IRAK 2.7.1.-
    369 ARAF1, PKS2, RAFA1 2.7.1.-
    370 ARAF2P, PKS1, ARAF2 2.7.1.-
    3984 LIMK1, LIMK 2.7.1.-
    3985 LIMK2 2.7.1.-
    4117 MAK 2.7.1.-
    4140 MARK3, KP78 2.7.1.-
    4215 MAP3K3, MAPKKK3, MEKK3 2.7.1.-
    4216 MAP3K4, MAPKKK4, MTK1, MEKK4,
    KIAA0213 2.7.1.-
    4217 MAP3K5, ASK1, MAPKKK5, MEKK5 2.7.1.-
    4293 MAP3K9, PRKE1, MLK1 2.7.1.-
    4294 MAP3K10, MLK2, MST 2.7.1.-
    4342 MOS 2.7.1.-
    4751 NEK2, NLK1 2.7.1.-
    4752 NEK3 2.7.1.-
    5058 PAK1, PAKalpha
    5062 PAK2, PAK65, PAKgamma 2.7.1.-
    5063 PAK3, MRX30, PAK3beta 2.7.1.-
    5127 PCTK1, PCTGAIRE 2.7.1.-
    5128 PCTK2 2.7.1.-
    5129 PCTK3, PCTAIRE 2.7.1.-
    5292 PIM1, PIM 2.7.1.-
    5347 PLK, PLK1 2.7.1.-
    5562 PRKAA1 2.7.1.-
    5563 PRKAA2, AMPK, PRKAA 2.7.1.-
    5578 PRKCA, PKCA 2.7.1.-
    5579 PRKCB1, PKCB, PRKCB, PRKCB2 2.7.1.-
    5580 PRKCD 2.7.1.-
    5581 PRKCE 2.7.1.-
    5582 PRKCG, PKCC, PKCG 2.7.1.-
    5583 PRKCH, PKC-L, PRKCL 2.7.1.-
    5584 PRKCI, DXS1179E, PKCI 2.7.1.-
    5585 PRKCLI, PAK1, PRK1, DBK, PKN 2.7.1.-
    5586 PRKCL2, PRK2 2.7.1.-
    5510 PRKCQ 2.7.1.-
    5590 PRKCZ 2.7.1.-
    5594 MAPK1, PRKM1, P41MAPK,
    P42MAPK, ERK2, ERK, MAPK2, 2.7.1.-
    PRKM2
    5595 MAPK3, ERK1, PRKM3, P44ERK1,
    P44MAPK 2.7.1.-
    5597 MAPK6, PRKM6, P97MAPK, ERK3 2.7.1.-
    5598 MAPK7, BMKI, ERK5, PRKM7 2.7.1.-
    5599 MAPK8, JNK, JNK1, SAPK1, PRKM8, 2.7.1.-
    JNK1A2
    5601 MAPK9, JNK2, PRKM9, P54ASAPK, 2.7.1.-
    JUNKINASE
    5602 MAPK10, JNK3, PRKM10, P493F12,
    P54BSAPK 2.7.1.-
    5603 MAPK13, SAPK4, PRKM13,
    P38DELTA 2.7.1.-
    5604 MAP2K1, MAPKK1, MEK1, MKK1,
    PRKMK1 2.7.1.-
    5605 MAP2K2, MEK2, PRKMK2 2.7.1.-
    5606 MAP2K3, MEK3, MKK3, PRKMK3 2.7.1.-
    5607 MAP2K5, MEK5, PRKMK5 2.7.1.-
    5608 MAP2K6, MEK6, MKK6, SAPKK3,
    PRKMK6 2.7.1.-
    5609 MAP2K7, MAPKK7, MKK7, PRKMK7,
    JNKK2 2.7.1.-
    5610 PRKR, EIF2AK1, PKR 2.7.1.-
    5613 PRKX, PKX1 2.7.1.-
    5894 RAF1 2.7.1.-
    613 BCR CML, PHL, BCR1 D22S11,
    D22S662 2.7.1.-
    6195 RPS6KA1, HU-1, RSK, RSK1,
    MAPKAPK1A 2.7.1.-
    6196 RPS6KA2, HU-2, MAPKAPKIC, RSK,
    RSK3 2.7.1.-
    6197 RPS6KA3, RSK2, HU-2, HU-3, RSK, 2.7.1.-
    MAPKAPK1B, ISPK-1
    6198 RPS6KB1, STK14A 2.7.1.-
    6199 RPS6KB2, P70-BETA, P70S6KB 2.7.1.-
    MAPK12, ERK6, PRKM12, SAPK3,
    6300 P38GAMMA, SAPK-3 2.7.1.-
    MAP2K4, JNKK1, MEK4, PRKMK4,
    6416 SERK1, MKK4 2.7.1.-
    6446 SGK 2.7.1.-
    658 BMPR1B, ALK-6, ALK6 2.7.1.-
    659 BMPR2, BMPR-II, BMPR3, BRK-3 2.7.1.-
    673 BRAF 2.7.1.-
    6792 STK9 2.7.1.-
    6794 STK11, LKB1, PJS 2.7.1.-
    6885 MAP3K7, TAK1 2.7.1.-
    699 BUB1 2.7.1.-
    701 BUB1B, BUBR1, MAD3L 2.7.1.-
    7016 TESK1 2.7.1.-
    7272 TTK, MPS1L1 2.7.1.-
    7867 MAPKAPK3, 3PK, MAPKAP3 2.7.1.-
    8408 ULK1 2.7.1.-
    8558 CDK10, PISSLRE 2.7.1.-
    8621 CDC2L5, CDC2L, CHED 2.7.1.-
    8737 RIPK1, RIP 2.7.1.-
    8814 CDKL1, KKIALRE 2.7.1.-
    8899 PRP4, PR4H 2.7.1.-
    9064 MAP3K6, MAPKKK6 2.7.1.-
    9149 DYRK1B 2.7.1.-
    92 ACVR2, ACTRII 2.7.1.-
    9201 DCAMKLI, KIAA0369 2.7.1.-
    93 ACVR2B 2.7.1.-
    983 CDC2 2.7.1.-
    984 CDC2L1 2.7.1.-
    5205 FIC1, BRIC, PFIC1, PFIC, ATP8B1 3.6.1.-
    DHPP -> DHP + PI
    GTP -> GSN + 3 PI
    DGTP -> DG + 3 PI
    7.2 Glycoprotein biosynthesis PATH: hsa00510
    1798 DPAGT1, DPAGT, UGAT, UAGT, 2.7.8.15
    D11S366, DGPT, DPAGT2, GPT
    29880 ALG5 2.4.1.117
    8813 DPM1 GDPMAN + DOLP -> GDP + DOLMANP 2.4.1.83
    1650 DDOST, OST, OST48, KIAA0115 2.4.1.119
    6184 RPN1 2.4.1.119
    6185 RPN2 2.4.1.119
    10130 P5 5.3.4.1
    10954 PDIR 3.3.4.1
    11008 PDI 5.3.4.1
    2923 GRP58, ERp57, ERp60, ERp61, 5.3.4.1
    GRP57, P58, PI-PLC, ERP57, ERP60,
    ERP61
    5034 P4HB, PROHB, PO4DB, ERBA2L 5.3.4.1
    7841 GCS1 3.2.1.106
    4121 MAN1A1, MAN9, HUMM9 3.2.1.113
    4245 MGAT1, GLYT1, GLCNAC-TI, GNT-I, 2.4.1.101
    MGAT
    4122 MAN2A2, MANA2X 3.2.1.114
    4124 MAN2A1, MANA2 3.2.1.114
    4247 MGAT2, CDGS2, GNT-II, GLCNACTII,
    GNT2 2.4.1.143
    4248 MGAT3, GNT-III 2.4.1.144
    6487 SIAT6, ST3GALII 2.4.99.6
    6480 SIAT1 2.4.99.1
    2339 FNTA, FPTA, PGGT1A 2.5.1.-
    2342 FNTB, FPTB 2.5.1.-
    5229 PGGT1B, BGGI, GGTI 2.5.1.-
    5875 RABGGTA 2.5.1.-
    5876 RABGGTB 2.5.1.-
    1352 COX10 2.5.1.-
    7.3 Glycoprotein degradation PATH: hsa00511
    4758 NEU1, NEU 3.2.1.18
    3073 HEXA, TSD 3.2.1.52
    3074 HEXB 3.2.1.52
    4123 MAN2C1, MANA, MANA1, MAN6A8 3.2.1.24
    4125 MAN2B1, MANS, LAMAN 3.2.1.24
    4126 MANBA, MANB1 3.2.1.25
    2517 FUCA1 3.2.1.51
    2519 FUCA2 3.2.1.51
    175 AGA, AGU 3.5.1.26
    7.4 Aminosugars metabolism PATH: hsa00530
    6675 UAP1, SPAG2, AGX1 UTP + NAGAI P <-> UDPNAG + PPI 2.7.7.23
    10020 GNE, GLCNE 5.1.3.14
    22951 CMAS 2.7.7.43
    1727 DIA1 1.6.2.2
    4669 NAGLU, NAG 3.2.1.50
    7.5 Lipopolysaccharide biosynthesis PATH: hsa00540
    6484 SIAT5, SAT3, STZ 2,4.99.-
    7903 SIAT8D, PST, PST1, ST8SIA-IV 2.4.99.-
    8128 SIAT8B, STX, STSSIA-II 2.4.99.-
    7.7 Glycosaminoglycan degradation PATH: hsa00531
    3423 IDS, MPS2, SIDS 3.1.6.13
    3425 IDUA, IDA 3.2.1.76
    411 ARSB 3.1.6.12
    2799 GNS, G6S 3.1.6.14
    2588 GALNS, MPS4A, GALNAC6S, GAS 3.1.6.4
    8. Metabolism of Complex Lipids
    8.1 Glycerolipid metabolism PATH: hsa00561
    10554 AGPAT1, LPAAT-ALPHA, G15 AGL3P + 0.017 C100ACP + 0.062 C120ACP + 0.100 C140ACP + 2.3.1.51
    0.270 C160ACP + 0.169 C161ACP + 0.055 C180ACP + 0.235
    C181ACP + 0.093 C182ACP -> PA + ACP
    10555 AGPAT2, LPAAT-BETA AGL3P + 0.017 C100ACP + 0.062 C120ACP + 0.100 C140ACP + 2.3.1.51
    0.270 C160ACP + 0.169 C161ACP + 0.055 C180ACP + 0.235
    C181ACP + 0.093 C182ACP -> PA + ACP
    1606 DGKA, DAGK, DAGK1 2.7.1.107
    1608 DGKG, DAGK3 2.7.1.107
    1609 DGKO, DAGK4 2.7.1.107
    8525 DGKZ, DAGK5, HDGKZETA 2.7.1.107
    8526 DGKE, DAGK6, DGK 2.7.1.107
    8527 DGKD, DGKDELTA, KIAA0145 2.7.1.107
    1120 CHKL ATP + CHO -> ADP + PCHO 2.7.1.32
    EKI1 ATP + ETHM -> ADP + PETHM 2.7.1.82
    1119 CHK, CKI ATP + CHO -> ADP + PCHO 2.7.1.32
    43 ACHE, YT 3.1.1.7
    1103 CHAT 2.3.1.6
    5337 PLD1 3.1.4.4
    26279 PLA2G2D, SPLA2S 3.1.1.4
    30814 PLA2G2E 3.1.1.4
    5319 PLA2G1B, PIA2, PLA2A, PPLA2 3.1.1.4
    5320 PLA2G2A, MOM1, PLA2B, PLA2L 3.1.1.4
    5322 PLA2G5 3.1.1.4
    8398 PLA2G6, IPLA2 3.1.1.4
    8399 PLA2G10, SPLA2 3.1.1.4
    1040 CDS1 PA + CTP <-> CDPDG + PPI 2.7.7.41
    10423 PIS CDPDG + MYOI -> CMP + PINS 2.7.8.11
    2710 GK GL + ATP -> GL3P + ADP 2.7.1.30
    2820 GPD2 GL3Pm + FADm -> T3P2m + FADH2m 1.1.99.5
    2819 GPD1 T3P2 + NADH <-> GL3P + NAD 1.1.1.8
    248 ALPI AHTD -> DHP + 3 PI 3.1.3.1
    249 ALPL, HOPS, TNSALP AHTD -> OHP + 3 PI 3.1.3.1
    250 ALPP AHTD -> DHP + 3 PI 3.1.3.1
    251 ALPPL2 AHTD -> DHP + 3 PI 3.1.3.1
    439 ASNA1, ARSA-I 3.6.1.16
    8694 DGAT, ARGP1 DAGLY + 0,017 C100ACP + 0.062 C120ACP + 0.100 C140ACP + 2.3.1.20
    0.270 C160ACP + 0.169 C161ACP + 0.055 C180ACP + 0.235
    C181ACP + 0.093 C182ACP -> TAGLY + ACP
    3989 LIPB 3.1.1.3
    3990 LIPC, HL 3.1.1.3
    5406 PNLIP 3.1.1.3
    5407 PNLIPRP1, PLRP1 3.1.1.4
    5408 PNLIPRP2, PLRP2 3.1.1.3
    8513 LIPF, HGL, HLAL 3.1.1.3
    4023 LPL, LIPD 3.1.1.34
    8443 GNPAT, DHAPAT, DAP-AT 2.3.1.42
    8540 AGPS, ADAP-S, ADAS, ADHAPS, 2.5.1.26
    ADPS, ALDHPSY
    4186 MDCR, MDS, L1S1 3.1.1.47
    5048 PAFAH1B1, LIS1, MDCR, PAFAH 3.1.1.47
    5049 PAFAH1B2 3.1.1.47
    5050 PAFAH1B3 3.1.1.47
    5051 PAFAH2, HSD-PLA2 3.1.1.47
    7941 PLA2G7, PAFAH, LDL-PLA2 3.1.1.47
    8.2 Inositol phosphate metabolism PATH: hsa00562
    5290 PIK3CA ATP + PINS -> ADP + PINSP 2.7.1.137
    5291 PIK3CB, PIK3C1 ATP + PINS -> ADP + PINSP 2.7.1.137
    5293 PIK3CD ATP + PINS -> ADP + PINSP 2.7.1.137
    5294 PIK3CG ATP + PINS -> ADP + PINSP 2.7.1.137
    5297 PIK4CA, PI4K-ALPHA ATP + PINS -> ADP + PINS4P 2.7.1.67
    5305 PIP5K2A PINS4P + ATP -> D45P1 + ADP 2.7.1.68
    5330 PLCB2 D45P1-> TPI + DAGLY 3.1.4.11
    5331 PLCB3 D45P1-> TPI + DAGLY 3.1.4.11
    5333 PLCD1 D45PI -> TPI + DAGLY 3.1.4.11
    5335 PLCG1, PLC1 D45PI -> TPI + DAGLY 3.1.4.11
    5336 PLCG2 D45PI -> TPI + DAGLY 3.1.4.11
    3612 IMPA1, IMPA MI1P -> MYO1+ PI 3.1.3.25
    3613 IMPA2 MI1P -> MYOI + PI 3.1.3.25
    3628 INPP1 3.1.3.57
    3632 INPP5A
    3633 INPP5B 3.1.3.56
    3636 INPPL1, SHIP2 3.1.3.56
    4952 OCRL, LOCR, OCRL1, INPP5F 3.1.3.56
    8867 SYNJ1, INPP5G 3.1.3.56
    3706 ITPKA 2.7.1.127
    51477 ISYNA1 G6P -> MI1P 5.5.1.4
    3631 INPP4A, INPP4 3.1.3.66
    8821 INPP4B 3.1.3.66
    8.3 Sphingophospholipid biosynthesis PATH: hsa00570
    6609 SMPD1, NPD 3.1.4.12
    8.4 Phospholipid degradation PATH: hsa00580
    1178 CLC 3.1.1.5
    5321 PLA2G4A, CPLA2-ALPHA, PLA2G4 3.1.1.5
    8.5 Sphingoglycolipid metabolism PATH: hsa00600
    10558 SPTLC1, LCB1, SPTI PALCOA + SER -> COA + DHSPH + CO2 2.3.1.50
    9517 SPTLC2, KIAA0526, LCB2 PALCOA + SER -> COA + DHSPH + CO2 2.3.1.50
    427 ASAH, AC, PHP32 3.5.1.23
    7357 UGCG, GCS 2.4.1.80
    2629 GBA, GLUC 3.2.1.45
    2583 GALGT, GALNACT 2.4.1.92
    6489 SIAT8A SIAT8, ST8SIA-I 2.4.99.8
    6481 SIAT2 2.4.99.2
    4668 NAGA, D22S674, GALB 3.2.1.49
    9514 CST 2.8.2.11
    410 ARSA, MLD 3.1.6.8
    8.6 Blood group glycolipid biosynthesis - loci series PATH: hsa00601
    28 ABO 2.4.1.40
    2.4.1.37
    2525 FUT3, LE 2.4.1.65
    2527 FUT5, FUC-TV 2.4.1.65
    2528 FUT6 2.4.1.65
    2523 FUT1, H, HH 2.4.1.69
    2524 FUT2, SE 2.4.1.69
    8.7 Blood group glycolipid biosynthesis - neolact series PATH:hsa00602
    2651 GCNT2, IGNT, NACGT1, NAGCT1 2.4.1.150
    8.8 Prostaglandin and leukotriene metabolism PATH:hsa00590
    239 ALOX12, LOG12 1.13.11.31
    246 ALOX15 1.13.11.33
    240 ALOX5 1.13.11.34
    4056 LTC4S 2.5.1.37
    4048 LTA4H 3.3.2.6
    4051 CYP4F3, CYP4F, LTB4H 1.14.13.30
    8529 CYP4F2 1.14.13.30
    5742 PTGS1, PGHS-1 1.14.99.1
    5743 PTGS2, COX-2, COX2 1.14.99.1
    27306 PGDS 5.3.99.2
    5730 PTGDS 5.3.99.2
    5740 PTGIS, CYP8, PGIS 5.3.99.4
    6916 TBXAS1, CYP5 5.3.99.5
    873 CBR1, CBR 1.1.1.184
    1.1.1.189
    1.1.1.197
    874 CBR3 1.1.1.184
    9. Metabolism of Cofactors and Vitamins
    9.2 Riboflavin metabolism PATH: hsa00740
    52 ACP1 3.1.3.48
    FMN -> RIBOFLAV + PI 3.1.3.2
    53 ACP2 FMN -> RIBOFLAV + PI 3.1.3.2
    54 ACP5, TRAP FMN -> RIBOFLAV + PI 3.1.3.2
    55 ACPP, PAP FMN -> RIBOFLAV + PI 3.1.3.2
    9.3 Vitamin 86 metabolism PATH: hssa00750
    8566 PDXK, PKH, PNK PYRDX + ATP -> P5P + ADP 2.7.1.35
    PDLA + ATP -> POLA5P + ADP
    PL + ATP -> PL5P + ADP
    9.4 Nicotinate and nicotinamide metabolism PATH: hsa00760
    23475 QPRT QA + PRPP -> NAMN + CO2 + PPI 2.4.2.19
    4837 NNMT 2.1.1.1
    683 BST1, CD157 NAO -> NAM + AOPRIB 3.2.2.5
    952 CD38 NAD -> NAM + AOPRIB 3.2.2.5
    23530 NNT 1.6.1.2
    9.5 Pantothenate and CoA biosynthesis PATH: hsa00770
    9.6 Biotin metabolism PATH: hsa00780
    3141 HLCS, HCS 6.3.4.-
    6.3.4.9
    6.3.4.10
    6.3.4.11
    6.3.4.15
    686 BTD
    9.7 Folate biosynthesis PATH: hsa00790
    2643 GCH1, DYT5, GCH, GTPCH1 GTP -> FOR + AHTD 3.5.4.16
    1719 DHFR DHF + NADPH -> NADP + THF 1.5.1.3
    2356 FPGS THF + ATP + GLU <-> ADP + PI + THFG 6.3.2.17
    8836 GGH, GH 3.4.19.9
    5805 PTS 4.6.1.10
    6697 SPR 1.1.1.153
    5860 QDPR, DHPR, PKU2 NADPH + DHBP -> NADP + THBP 1.6.99.7
    9.8 One carbon pool by folate PATH: hsa00670
    10840 FTHFD 1.5.1.6
    10588 MTHFS ATP + FTHF -> ADP + PI + MTHF 6.3.3.2
    9.10 Porphyrin and chlorophyll metabolism PATH: hsa00860
    210 ALAD 2 ALAV -> PBG 4.2.1.24
    3145 HMBS, PBGD, UPS 4 PBG -> HMB + 4 NH3 4.3.1.8
    7390 UROS HMB -> UPRG 4.2.1.75
    7389 UROD UPRG -> 4 CO2 + CPP 4.1.1.37
    1371 CPO, CPX O2 + CPP -> 2 CO2 + PPHG 1.3.3.3
    5498 PPDX, PPO O2 + PPHGm -> PPIXm 1.3.3.4
    2235 FECH, FCE PPIXm -> PTHm 4.99.1.1
    3162 HMOX1, HO-1 1.14.99.3
    3163 HMOX2, 140-2 1.14.99.3
    644 BLVRA, BLVR 1.3.1.24
    645 BLVR8, FLR 1.3.1.24
    1.6.99.1
    2232 FDXR, ADXR 1.18.1.2
    3052 HCCS, CCHL 4.4.1.17
    1356 CP 1.16.3.1
    9.11 Ubiquinone biosynthesis PATH: hsa00130
    4938 OAS1, IFI-4, OIAS 2.7.7.-
    4939 OAS2, P69 2.7.7.-
    5557 PRIM1 2.7.7.-
    5558 PRIM2A, PRIM2 2.7.7.-
    5559 PRIM2B, PRIM2 2.7.7.-
    7015 TERT, EST2, TCS1, TP2, TRT 2.7.7.-
    8638 OASL, TRIP14 2.7.7.-
    10. Metabolism of Other Substances
    10.1 Terpenoid biosynthesis PATH: hsa00900
    10.2 Flavonoids, stilbene and lignin biosynthesis PATH: hsa00940
    10.3 Alkaloid biosynthesis I PATH: hsa00950
    10.4 Alkaloid biosynthesis II PATH: hsa00960
    10.6 Streptomycin biosynthesis PATH: hsa00521
    10.7 Erythromycin biosynthesis PATH: hsa00522
    10.8 Tetracycline biosynthesis PATH: hsa00253
    10.14 gamma-Hexachlorocyclohexane degradation PATH: hsa00361
    5444 PON1, ESA, PON 3.1.8.1
    3.1.1.2
    5445 PON2 3.1.1.2
    3.1.8.1
    10.18 1,2-Dichloroethane degradation PATH: hsa00631
    10.20 Tetrachloroethene degradation PATH: hsa00625
    2052 EPHX1, EPHX, MEH 3.3.2.3
    2053 EPHX2 3.3.2.3
    10.21 Styrene degradation PATH: hsa00643
    11. Transcription (condensed)
    11.1 RNA polymerase PATH: hsa03020
    11.2 Transcription factors PATH: hsa03022
    12. Translation (condensed)
    12.1 Ribosome PATH: hsa03010
    12.2 Translation factors PATH: hsa03012
    1915 EEF1A1, EF1A, ALPHA, EEF-1,
    EEF1A 3.6.1.48
    1917 EEF1A2, EF1A 3.6.1.48
    1938 EEF2, EF2, EEF-2 3.6.1.48
    12.3 Aminoacyl-tRNA biosynthesis PATH: hsa00970
    13. Sorting and Degradation (condensed)
    13.1 Protein export PATH: hsa03060
    23478 SPC18 3.4.21.89
    13.4 Proteasome PATH: hsa03050
    5687 PSMA6, IOTA, PROS27 3.4.99.46
    5683 PSMA2, HC3, MU, PMSA2, PSC2 3.4.99.46
    5685 PSMA4, HC9 3.4.99.46
    5688 PSMA7, XAPC7 3.4.99.46
    5686 PSMAS, ZETA, PSC5 3.4.99.46
    5682 PSMA1, HC2, NU, PROS30 3.4.99.46
    5684 PSMA3, HC8 3.4.99.46
    5698 PSMB9, LMP2, RING12 3.4.99.46
    5695 PSMB7, Z 3.4.99.46
    5691 PSMB3, HC10-II 3.4.99.46
    5690 PSMB2, HC7-I 3.4.99.46
    5693 PSMB5, LMPX, MB1 3.4.99.46
    5689 PSMB1, HCS, PMSB1 3.4.99.46
    5692 PSMB4, HN3, PROS26 3.4.99.46
    14. Replication and Repair
    14.1 DNA polymerase PATH: hsa03030
    14.2 Replication Complex PATH: hsa03032
    23626 SPO11 5.99.1.3
    7153 TOP2A, TOP2 5.99.1.3
    7155 TOP2B 5.99.1.3
    7156 TOP3A, TOP3 5.99.1.2
    TOP3B 5.99.1.2
    22. Enzyme Complex
    22.1 Electron Transport System, Complex I PATH: hsa03100
    22.2 Electron Transport System, Complex II PATH: hsa03150
    22.3 Electron Transport System, Complex III PATH: hsa03140
    22.4 Electron Transport System, Complex IV PATH: hsa03130
    22.5 ATP Synthase PATH: hsa03110
    22.8 ATPases PATH: hsa03230
    23. Unassigned
    23.1 Enzymes
    5538 PPT1, CLN1, PPT, INCL C160ACP + H2O -> C160 + ACP 3.1.2.22
    23.2 Non-enzymes
    22934 RPIA, RPI RL5P <-> R5P 5.3.1.6
    5250 SLC25A3, PHC PI + H <-> Hm + Plm
    6576 CIT + MALm <-> CITm + MAL
    51166 LOC51168 AADP + AKG -> GLU + KADP 2.6.1.39
    5625 PRODH PRO + FAD -> P5C + FADH2 1.5.3.-
    6517 SLC2A4, GLUT4 GLCxt -> GLC
    6513 SLC2A1, GLUT1, GLUT GLCxt -> GIG
    26275 HIBCH, HIBYL-COA-H HIBCOAm + H2Om -> HIBm + COAm 3.1.2.4
    23305 KIAA0837, ACS2, LACS5, IACS2 C160 + COA + ATP -> AMP + PPI + C160COA
    8611 PPAP2A, PAP-2A PA + H2O -> DAGLY + PI
    8612 PPAP2C, PAP-2C PA + H2O -> DAGLY + PI
    8613 PPAP2B, PAP-28 PA + H2O -> DAGLY + PI
    56994 LOC56994 CDPCHO + DAGLY -> PC + CMP
    10400 PEMT, PEMT2 SAM + PE -> SAH + PMME
    5833 PCYT2, ET PETHM + CTP -? CDPETN + PPI
    10390 CEPT1 CDPETN + DAGLY <-> CMP + PE
    8394 PIP5K1A PINS4P + ATP -> D45PI + ADP
    8395 P1P5K1B, STMT, MSS4 PINS4P + ATP -> D45PI + ADP
    8396 PIP5K2B PINS4P + ATP -> D45PI + ADP
    23396 PIP5K1C, KIAA0589, PIP5K-GAMMA PINS4P + ATP -> D45PI + ADP
    24. Our own reactions which need to be found in KEGG
    GL3P <-> GL3Pm
    T3P2 <-> T3P2m
    PYR <-> PYRm + Hm
    ADP + ATPm + PI + H -> Hm + ADPm + ATP + Plm
    AKG + MAIm <-> AKGm + MAL
    ASPm + GLU + H -> Hm + GLUm + ASP
    GDP + GTPm + PI + H -> Hm + GDPm + GTP + Plm
    C160Axt + FABP -> C160FP + ALBxt
    C160FP -> C160 + FABP
    C180Axt + FABP -> C180FP + ALBxt
    C180FP -> C180 + FABP
    C161Axt + FABP -> C161FP + ALBxt
    C161FP -> C161 + FABP
    C181Axt + FABP -> C181FP + ALBxt
    C181FP -> C181 + FABP
    C182Axt + FABP -> C182FP + ALBxt
    C182FP -> C182 + FABP
    C204Axt + FABP -> C204FP + ALBxt
    C204FP -> C204 + FABP
    O2xt -> O2
    O2 <-> O2m
    ACTACm + SUCCOAm -> SUCCm + AACCOAm
    3HB -> 3HBm
    MGCOAm + H2Om -> H3MCOAm 4.2.1.18
    OMVAL -> OMVALm
    OIVAL -> OIVALm
    OICAP -> OICAPm
    C160CAR <-> C160CARm
    CAR <-> CARm
    DMMCOAm -> LMMCOAm 5.1.99.1
    amino acid metabolism
    THR -> NH3 + H2O + OBUT 4.2.1.16
    THR + NAD -> CO2 + NADH + AMA 1.1.1.103
    THR + NAD + COA -> NADH + ACCOA + GLY
    MSA + NAD -> NADH + AADP 1.2.1.31
    FKYN + H2O -> FOR + KYN 3.5.1.9
    CMUSA -> CO2 + AM6SA 4.1.1.4
    AM6SA + NAD -> AMUCO + NADH 1.2.1.32
    AMUCO + NADPH -> KADP + NADP + NH4 1.5.1.-
    CYSS + MG <-> GLU + SPYR
    URO + H2O -> 4I5P 4.2.1.49
    4I5P + H2O -> FIGLU 3.5.2.7
    GLU <-> GLUm + Hm
    ORN + Hm -> ORNm
    ORN + Hm + CITRm <-> CITR + ORNm
    GLU + ATP + NADPH -> NADP + ADP + PI + GLUGSAL
    GLYAm + ATPm -> ADPm + 2PGm
    AM6SA -> PIC
    SPYR + H2O -> H2SO3 + PYR
    P5C <-> GLUGSAL
    fatty acid synthesis
    MALCOA + ACP <-> MALACP + COA 2.3.1.39
    ACCOA + ACP <-> ACACP + COA
    ACACP + 4 MALACP + 8 NADPH -> 8 NADP + C100ACP + 4
    CO2 + 4 ACP
    ACACP + 5 MALACP + 10 NADPH -> 10 NADP + C120ACp + 5
    CO2 + 5 ACP
    ACACP + 6 MALACP + 12 NADPH -> 12 NADP + C140ACP + 6
    CO2 + 6 ACP
    ACACP + 6 MALACP + 11 NADPH -> 11 NADP + C141ACP + 6
    CO2 + 6 ACP
    ACACP + 7 MALACP + 14 NADPH -> 14 NADP + C160ACP + 7
    CO2 + 7 ACP
    ACACP + 7 MALACP + 13 NADPH -> 13 NADP + C181ACP + 7
    CO2 + 7 ACP
    ACACP + 8 MALACP + 16 NADPH -> 16 NADP + C180ACP + 8
    CO2 + 8 ACP
    ACACP + 8 MALACP + 15 NADPH -> 15 NADP + C181ACP + 8
    CO2 + 8 ACP
    ACACP + 8 MALACP + 14 NADPH -> 14 NADP + C182ACP + 8
    CO2 + 8 ACP
    C160COA + CAR -> C160CAR + COA
    fatty acid depredation C160CARm + COAm -> C160COAm + CARm
    GL3P + 0.017 C100ACP + 0.062 C120ACP + 0.1 C140ACP +
    0.27 C160ACP + 0.169 C161ACP + 0.055 C180ACP + 0.235
    C181ACP + 0.093 C182ACP -> AGL3P + ACP
    TAGLYm + 3 H2Om -> GLm + 3 C160m
    Phospholipid metabolism
    SAM + PMME -> SAH + PDME
    PDME + SAM -> PC + SAH
    PE + SER <-> PS + ETHM
    Muscle contraction
    MYOACT + ATP -> MYOATP + ACTIN
    MYOATP + ACTIN -> MYOADPAC
    MYOADPAC -> ADP + PI + MYOACT + CONTRACT
  • TABLE 2
    // Homo Sapiens Core Metabolic Network //
    // Glycolysis //
    −1 GLC −1 ATP +1 G6P +1 ADP  0 HK1
    −1 G6P −1 H2O +1 GLC +1 PI  0 G6PC
    −1 G6P +1 F6P  0 GPIR
    −1 F6P −1 ATP +1 FDP +1 ADP  0 PFKL
    −1 FDP −1 H2O +1 F6P +1 PI  0 FBP1
    −1 FDP +1 T3P2 +1 T3P1  0 ALDOAR
    −1 T3P2 +1 T3P1  0 TPI1R
    −1 T3P1 −1 PI −1 NAD +1 NADH +1 13PDG  0 GAPDR
    −1 13PDG −1 ADP +1 3PG +1 ATP  0 PGK1R
    −1 13PDG +1 23PDG  0 PGAM1
    −1 23PDG −1 H2O +1 3PG +1 PI  0 PGAM2
    −1 3PG +1 2PG  0 PGAM3R
    −1 2PG +1 PEP +1 H2O  0 ENO1R
    −1 PEP −1 ADP +1 PYR +1 ATP  0 PKLR
    −1 PYRm −1 COAm −1 NADm +1 NADHm +1 CO2m +1 ACCOAm
    0 PDHA1
    −1 NAD −1 LAC +1 PYR +1 NADH 0 LDHAR
    −1 G1P +1 G6P  0 PGM1R
    // TCA //
    −1 ACCOAm −1 OAm −1 H2Om +1 COAm +1 CITm  0 CS
    −1 CIT +1 ICIT  0 ACO1R
    −1 CITm +1 ICITm  0 ACO2R
    −1 ICIT −1 NADP +1 NADPH +1 CO2 +1 AKG  0 IDH1
    −1 ICITm −1 NADPm +1 NADPHm +1 CO2m +1 AKGm  0 IDH2
    −1 ICITm −1 NADm +1 CO2m +1 NADHm +1 AKGm  0 IDH3A
    −1 AKGm −1 NADm −1 COAm +1 CO2m +1 NADHm +1 SUCCOAm
    0 OGDH
    −1 GTPm −1 SUCCm −1 COAm +1 GDPm +1 PIm +1 SUCCOAm
    0 SUCLG1R
    −1 ATPm −1 SUCCm −1 COAm +1 ADPm +1 PIm +1 SUCCOAm
    0 SUCLA2R
    −1 FUMm −1 H2Om +1 MALm  0 FHR
    −1 MAL −1 NAD +1 NADH +1 OA  0 MDH1R
    −1 MALm −1 NADm +1 NADHm +1 OAm  0 MDH2R
    −1 PYRm −1 ATPm −1 CO2m +1 ADPm +1 OAm +1 PIm  0 PC
    −1 OA −1 GTP +1 PEP +1 GDP +1 CO2  0 PCK1
    −1 OAm −1 GTPm +1 PEPm +1 GDPm +1 CO2m  0 PCK2
    −1 ATP −1 CIT −1 COA −1 H2O +1 ADP +1 PI +1 ACCOA +1 OA
    0 ACLY
    // PPP //
    −1 G6P −1 NADP +1 D6PGL +1 NADPH  0 G6PDR
    −1 D6PGL −1 H2O +1 D6PGC  0 PGLS
    −1 D6PGC −1 NADP +1 NADPH +1 CO2 +1 RL5P  0 PGD
    −1 RL5P +1 X5P  0 RPER
    −1 R5P −1 X5P +1 T3P1 +1 S7P  0 TKT1R
    −1 X5P −1 E4P +1 F6P +1 T3P1  0 TKT2R
    −1 T3P1 −1 S7P +1 E4P +1 F6P   0 TALDO1R
    −1 RL5P +1 R5P  0 RPIAR
    // Glycogen //
    −1 G1P −1 UTP +1 UDPG +1 PPI  0 UGP1
    −1 UDPG +1 UDP +1 GLYCOGEN  0 GYS1
    −1 GLYCOGEN −1 PI +1 G1P  0 GBE1
    // ETS //
    −1 MALm −1 NADPm +1 CO2m +1 NADPHm +1 PYRm  0 ME3
    −1 MALm −1 NADm +1 CO2m +1 NADHm +1 PYRm  0 ME2
    −1 MAL −1 NADP +1 CO2 +1 NADPH +1 PYR  0 ME1
    −1 NADHm −1 Qm −4 Hm +1 QH2m +1 NADm +4 H  0 MTND1
    −1 SUCCm −1 FADm +1 FUMm +1 FADH2m  0 SDHC1R
    −1 FADH2m −1 Qm +1 FADm +1 QH2m 0 SDHC2R
    −1 O2m −4 FEROm −4 Hm +4 FERIm +2 H2Om +4 H 0 UQCRFS1
    −1 QH2m −2 FERIm −4 Hm +1 Qm +2 FEROm +4 H 0 COX5BL4
    −1 ADPm −1 PIm −3 H +1 ATPm +3 Hm +1 H2Om 0 MTAT
    −1 ADP −1 ATPm −1 PI −1 H +1 Hm +1 ADPm +1 ATP +1 PIm
    0 ATPMC
    −1 GDP −1 GTPm −1 PI −1 H +1 Hm +1 GDPm +1 GTP +1 PIm
    0 GTPMC
    −1 PPI +2 PI  0 PP
    −1 ACCOA −1 ATP −1 CO2 +1 MALCOA +1 ADP +1 PI  0 ACACAR
    −1 GDP −1 ATP +1 GTP +1 ADP  0 GOT3R
    // Transporters //
    −1 CIT −1 MALm +1 CITm +1 MAL  0 CITMCR
    −1 PYR −1 H +1 PYRm +1 Hm  0 PYRMCR
    // Glycerol Phosphate Shuttle //
    −1 GL3Pm −1 FADm +1 T3P2m +1 FADH2m  0 GPD2
    −1 T3P2 −1 NADH +1 GL3P +1 NAD  0 GPD1
    −1 GL3P +1 GL3Pm  0 GL3PMCR
    −1 T3P2 +1 T3P2m  0 T3P2MCR
    // Malate/Aspartate Shuttle //
    −1 OAm −1 GLUm +1 ASPm +1 AKGm  0 GOT1R
    −1 ASP −1 AKG +1 OA +1 GLU  0 GOT2R
    −1 AKG −1 MALm +1 AKGm +1 MAL  0 MALMCR
    −1 ASPm −1 GLU −1 H +1 Hm +1 GLUm +1 ASP  0 ASPMC
    // Exchange Fluxes //
    +1 GLC 0 GLCexR
    +1 PYR 0 PYRexR
    +1 CO2 0 CO2exR
    +1 O2 0 O2exR
    +1 PI 0 PIexR
    +1 H2O 0 H2OexR
    +1 LAC 0 LACexR
    +1 CO2m 0 CO2min
    −1 CO2m 0 CO2mout
    +1 O2m 0 O2min
    −1 O2m 0 O2mout
    +1 H2Om 0 H2Omin
    −1 H2Om 0 H2Omout
    +1 PIm 0 PImin
    −1 PIm 0 Plmout
    // Output //
    −1 ATP +1 ADP +1 PI 0 Output
    0.0 end
    end E
    0
    max
    1 Output
    0 end
    0 GLCexR 1
    −1000 PYRexR 0
    −1000 LACexR 0
    0 end 0
    rev. rxn 33
    nonrev. rxn 31
    total rxn 64
    matrix columns 97
    unique enzymes 52
  • TABLE 3
    Abbrev. Reaction Rxn Name
    Glycolysis
    HK1 GLC + ATP -> G6P + ADP HK1
    G6PC, G6PT G6P + H2O -> GLC + PI G6PC
    GPI G6P <-> F6P GPI
    PFKL F6P + ATP -> FDP + ADP PFKL
    FBP1, FBP FDP + H2O -> F6P + PI FBP1
    ALDOA FDP <-> T3P2 + T3P1 ALDOA
    TPI1 T3P2 <-> T3P1 TPI1
    GAPD, GAPDH T3P1 + PI + NAD <-> NADH + 13PDG GAPD
    PGK1, PGKA 13PDG + ADP <-> 3PG + ATP PGK1
    PGAM1, PGAMA 13PDG <-> 23PDG PGAM1
    23PDG + H2O -> 3PG + PI PGAM2
    3PG <-> 2PG PGAM3
    ENO1, PPH, ENO1L1 2PG <-> PEP + H2O ENO1
    PKLR, PK1 PEP + ADP -> PYR + ATP PKLR
    PDHA1, PHE1A, PDHA PYRm + COAm + NADm -> + NADHm + CO2m + ACCOAm PDHA1
    LDHA, LDH1 NAD + LAC <-> PYR + NADH LDHA
    PGM1 G1P <-> G6P PGM1
    TCA
    CS ACCOAm + OAm + H2Om -> COAm + CITm CS
    ACO1, IREB1, IRP1 CIT <-> ICIT ACO1
    ACO2 CITm <-> ICITm ACO2
    IDH1 ICIT + NADP -> NADPH + CO2 + AKG IDH1
    IDH2 ICITm + NADPm -> NADPHm + CO2m + AKGm IDH2
    IDH3A ICITm + NADm -> CO2m + NADHm + AKGm IDH3A
    OGDH AKGm + NADm + COAm -> CO2m + NADHm + SUCCOAm OGDH
    SUCLG1, SUCLA1 GTPm + SUCCm + COAm <-> GDPm + PIm + SUCCOAm SUCLG1
    SUCLA2 ATPm + SUCCm + COAm <-> ADPm + PIm + SUCCOAm SUCLA2
    FH FUMm + H2Om <-> MALm FH
    MDH1 MAL + NAD <-> NADH + OA MDH1
    MDH2 MALm + NADm <-> NADHm + OAm MDH2
    PC, PCB PYRm + ATPm + CO2m -> ADPm + OAm + PIm PC
    ACLY, ATPCL, CLATP ATP + CIT + COA + H2O -> ADP + PI + ACCOA + OA ACLY
    PCK1 OA + GTP -> PEP + GDP + CO2 PCK1
    PPP
    G6PD, G6PD1 G6P + NADP <-> D6PGL + NADPH G6PD
    PGLS, 6PGL D6PGL + H2O -> D6PGC PGLS
    PGD D6PGC + NADP -> NADPH + CO2 + RL5P PGD
    RPE RL5P <-> X5P RPE
    TKT R5P + X5P <-> T3P1 + S7P TKT1
    X5P + E4P <-> F6P + T3P1 TKT2
    TALDO1 T3P1 + S7P <-> E4P + F6P TALDO1
    UGP1 G1P + UTP -> UDPG + PPI UGP1
    ACACA, ACAC, ACC ACCOA + ATP + CO2 <-> MALCOA + ADP + PI + H ACACA
    ETS
    ME3 MALm + NADPm -> CO2m + NADPHm + PYRm ME3
    MTND1 NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H MTND1
    SDHC SUCCm + FADm <-> FUMm + FADH2m SDHC1
    FADH2m + Qm <-> FADm + QH2m SDHC2
    UQCRFS1, RIS1 O2m + 4 FEROm + 4 Hm -> 4 FERIm + 2 H2Om + 4 H UQCRFS1
    COX5BL4 QH2m + 2 FERIm + 4 Hm -> Qm + 2 FEROm + 4 H COX5BL4
    MTATP6 ADPm + PIm + 3 H -> ATPm + 3 Hm + H2Om MTAT
    PP, SID6-8061 PPI -> 2 PI PP
    Malate Aspartate shunttle
    GOT1 OAm + GLUm <-> ASPm + AKGm GOT1
    GOT2 OA + GLU <-> ASP + AKG GOT2
    GDP + ATP <-> GTP + ADP GOT3
    Glycogen
    GBE1 GLYCOGEN + PI -> G1P GBE1
    GYS1, GYS UDPG -> UDP + GLYCOGEN GYS1
    Glycerol Phosphate Shunttle
    GPD2 GL3Pm + FADm -> T3P2m + FADH2m GPD2
    GPD1 T3P2 + NADH -> GL3P + NAD GPD1
    RPIA, RPI RL5P <-> R5P RPIA
    Mitochondria Transport
    CIT + MALm <-> CITm + MAL CITMC
    GL3P <-> GL3Pm GL3PMC
    T3P2 <-> T3P2m T3P2MC
    PYR <-> PYRm + Hm PYRMC
    ADP + ATPm + PI + H -> Hm + ADPm + ATP + PIm ATPMC
    AKG + MALm <-> AKGm + MAL MALMC
    ASPm + GLU + H -> Hm + GLUm + ASP ASPMC
    GDP + GTPm + PI + H -> Hm + GDPm + GTP + PIm GTPMC
  • TABLE 4
    Metabolic Reaction for Muscle Cells
    Reaction Rxt Name
    GLC + ATP -> G6P + ADP 0 HK1
    G6P <-> F6P 0 GPI
    F6P + ATP -> FDP + ADP 0 PFKL1
    FDP + H2O -> F6P + PI 0 FBP1
    FDP <-> T3P2 + T3P1 0 ALDOA
    T3P2 <-> T3P1 0 TPI1
    T3P1 + PI + NAD <-> NADH + 13PDG 0 GAPD
    13PDG + ADP <-> 3PG + ATP 0 PGK1
    3PG <-> 2PG 0 PGAM3
    2PG <-> PEP + H2O 0 ENO1
    PEP + ADP -> PYR + ATP 0 PK1
    PYRm + COAm + NADm -> + NADHm + CO2m + ACCOAm 0 PDHA1
    NAD + LAC <-> PYR + NADH 0 LDHA
    G1P <-> G6P 0 PGM1
    ACCOAm + OAm + H2Om -> COAm + CITm 0 CS
    CIT <-> ICIT 0 ACO1
    CITm <-> ICITm 0 ACO2
    ICIT + NADP -> NADPH + CO2 + AKG 0 IDH1
    ICITm + NADPm -> NADPHm + CO2m + AKGm 0 IDH2
    ICITm + NADm -> CO2m + NADHm + AKGm 0 IDH3A
    AKGm + NADm + COAm -> CO2m + NADHm + SUCCOAm 0 OGDH
    GTPm + SUCCm + COAm <-> GDPm + PIm + SUCCOAm 0 SUCLG1
    ATPm + SUCCm + COAm <-> ADPm + PIm + SUCCOAm 0 SUCLA2
    FUMm + H2Om <-> MALm 0 FH
    MAL + NAD <-> NADH + OA 0 MDH1
    MALm + NADm <-> NADHm + OAm 0 MDH2
    PYRm + ATPm + CO2m -> ADPm + OAm + PIm 0 PC
    ATP + CIT + COA + H2O -> ADP + PI + ACCOA + OA 0 ACLY
    OA + GTP -> PEP + GDP + CO2 0 PCK1
    OAm + GTPm -> PEPm + GDPm + CO2m 0 PCK2
    G6P + NADP <-> D6PGL + NADPH 0 G6PD
    D6PGL + H2O -> D6PGC 0 H6PD
    D6PGC + NADP -> NADPH + CO2 + RL5P 0 PGD
    RL5P <-> X5P 0 RPE
    R5P + X5P <-> T3P1 + S7P 0 TKT1
    X5P + E4P <-> F6P + T3P1 0 TKT2
    T3P1 + S7P <-> E4P + F6P 0 TALDO1
    RL5P <-> R5P 0 RPIA
    G1P + UTP -> UDPG + PPI 0 UGP1
    GLYCOGEN + PI -> G1P 0 GBE1
    UDPG -> UDP + GLYCOGEN 0 GYS1
    MALm + NADm -> CO2m + NADHm + PYRm 0 ME2
    MALm + NADPm -> CO2m + NADPHm + PYRm 0 ME3
    MAL + NADP -> CO2 + NADPH + PYR 0 HUMNDME
    NADHm + Qm + 4 Hm -> QH2m + NADm + 4 H 0 MTND1
    SUCCm + FADm <-> FUMm + FADH2m 0 SDHC1
    FADH2m + Qm <-> FADm + QH2m 0 SDHC2
    O2m + 4 FEROm + 4 Hm -> 4 FERIm + 2 H2Om + 4 H 0 UQCRFS1
    QH2m + 2 FERIm + 4 Hm -> Qm + 2 FEROm + 4 H 0 COX5BL4
    ADPm + PIm + 3 H -> ATPm + 3 Hm + H2Om 0 MTAT1
    ADP + ATPm + PI + H -> Hm + ADPm + ATP + PIm 0 ATPMC
    GDP + GTPm + PI + H -> Hm + GDPm + GTP + PIm 0 GTPMC
    PPI -> 2 PI 0 PP
    GDP + ATP <-> GTP + ADP 0 NME1
    ACCOA + ATP + CO2 <-> MALCOA + ADP + PI + H 0 ACACA
    MALCOA + ACP <-> MALACP + COA 0 FAS1_1
    ACCOA + ACP <-> ACACP + COA 0 FAS1_2
    ACACP + 4 MALACP + 8 NADPH -> 8 NADP + C100ACP + 4 CO2 + 4 ACP 0 C100SY
    ACACP + 5 MALACP + 10 NADPH -> 10 NADP + C120ACP + 5 CO2 + 5 0 C120SY
    ACP
    ACACP + 6 MALACP + 12 NADPH -> 12 NADP + C140ACP + 6 CO2 + 6 0 C140SY
    ACP
    ACACP + 6 MALACP + 11 NADPH -> 11 NADP + C141ACP + 6 CO2 + 6 0 C141SY
    ACP
    ACACP + 7 MALACP + 14 NADPH -> 14 NADP + C160ACP + 7 CO2 + 7 0 C160SY
    ACP
    ACACP + 7 MALACP + 13 NADPH -> 13 NADP + C161ACP + 7 CO2 + 7 0 C161SY
    ACP
    ACACP + 8 MALACP + 16 NADPH -> 16 NADP + C180ACP + 8 CO2 + 8 0 C180SY
    ACP
    ACACP + 8 MALACP + 15 NADPH -> 15 NADP + C181ACP + 8 CO2 + 8 0 C181SY
    ACP
    ACACP + 8 MALACP + 14 NADPH -> 14 NADP + C182ACP + 8 CO2 + 8 0 C182SY
    ACP
    C160ACP + H2O -> C160 + ACP 0 PPT1
    C160 + COA + ATP -> AMP + PPI + C160COA 0 KIAA
    C160COA + CAR -> C160CAR + COA 0 C160CA
    C160CARm + COAm -> C160COAm + CARm 0 C160CB
    C160CARm + COAm + FADm + NADm -> FADH2m + NADHm + 0 HADHA
    C140COAm + ACCOAm
    C140COAm + 7 COAm + 7 FADm + 7 NADm -> 7 FADH2m + 7 NADHm + 7 0 HADH2
    ACCOAm
    TAGLYm + 3 H2Om -> GLm + 3 C160m 0 TAGRXN
    GL3P + 0.017 C100ACP + 0.062 C120ACP + 0.1 C140ACP + 0.27 0 GAT1
    C160ACP + 0.169 C161ACP + 0.055 C180ACP + 0.235 C181ACP + 0.093
    C182ACP -> AGL3P + ACP
    AGL3P + 0.017 C100ACP + 0.062 C120ACP + 0.100 C140ACP + 0.270 0 AGPAT1
    C160ACP + 0.169 C161ACP + 0.055 C180ACP + 0.235 C181ACP + 0.093
    C182ACP -> PA + ACP
    ATP + CHO -> ADP + PCHO 0 CHKLT1
    PCHO + CTP -> CDPCHO + PPI 0 PCYT1A
    CDPCHO + DAGLY -> PC + CMP 0 LOC
    SAM + PE -> SAH + PMME 0 PEMT
    SAM + PMME -> SAH + PDME 0 MFPS
    PDME + SAM -> PC + SAH 0 PNMNM
    G6P -> MI1P 0 ISYNA1
    MI1P -> MYOI + PI 0 IMPA1
    PA + CTP <-> CDPDG + PPI 0 CDS1
    CDPDG + MYOI -> CMP + PINS 0 PIS
    ATP + PINS -> ADP + PINSP 0 PIK3CA
    ATP + PINS -> ADP + PINS4P 0 PIK4CA
    PINS4P + ATP -> D45PI + ADP 0 PIP5K1
    D45PI -> TPI + DAGLY 0 PLCB2
    PA + H2O -> DAGLY + PI 0 PPAP2A
    DAGLY + 0.017 C100ACP + 0.062 C120ACP + 0.100 C140ACP + 0.270 0 DGAT
    C160ACP + 0.169 C161ACP + 0.055 C180ACP + 0.235 C181ACP + 0.093
    C182ACP -> TAGLY + ACP
    CDPDG + SER <-> CMP + PS 0 PTDS
    CDPETN + DAGLY <-> CMP + PE 0 CEPT1
    PE + SER <-> PS + ETHM 0 PESER
    ATP + ETHM -> ADP + PETHM 0 EKI1
    PETHM + CTP -> CDPETN + PPI 0 PCYT2
    PS -> PE + CO2 0 PISD
    3HBm + NADm -> NADHm + Hm + ACTACm 0 BDH
    ACTACm + SUCCOAm -> SUCCm + AACOAm 0 3OCT
    THF + SER <-> GLY + METTHF 0 SHMT1
    THFm + SERm <-> GLYm + METTHFm 0 SHMT2
    SERm + PYRm <-> ALAm + 3HPm 0 AGXT
    3PG + NAD <-> NADH + PHP 0 PHGDH
    PHP + GLU <-> AKG + 3PSER 0 PSA
    3PSER + H2O -> PI + SER 0 PSPH
    3HPm + NADHm -> NADm + GLYAm 0 GLYD
    SER -> PYR + NH3 + H2O 0 SDS
    GLYAm + ATPm -> ADPm + 2PGm 0 GLTK
    PYR + GLU <-> AKG + ALA 0 GPT
    GLUm + CO2m + 2 ATPm -> 2 ADPm + 2 PIm + CAPm 0 CPS1
    AKGm + NADHm + NH3m <-> NADm + H2Om + GLUm 0 GLUD1
    AKGm + NADPHm + NH3m <-> NADPm + H2Om + GLUm 0 GLUD2
    GLUm + NH3m + ATPm -> GLNm + ADPm + PIm 0 GLUL
    ASPm + ATPm + GLNm -> GLUm + ASNm + AMPm + PPIm 0 ASNS
    ORN + AKG <-> GLUGSAL + GLU 0 OAT
    GLU <-> GLUm + Hm 0 GLUMT
    GLU + ATP + NADPH -> NADP + ADP + PI + GLUGSAL 0 P5CS
    GLUP + NADH -> NAD + PI + GLUGSAL 0 PYCS
    P5C <-> GLUGSAL 0 SPTC
    HIS -> NH3 + URO 0 HAL
    URO + H2O -> 4I5P 0 UROH
    4I5P + H2O -> FIGLU 0 IMPR
    FIGLU + THF -> NFTHF + GLU 0 FTCD
    MET + ATP + H2O -> PPI + PI + SAM 0 MAT1A
    SAM + DNA -> SAH + DNA5MC 0 DNMT1
    SAH + H2O -> HCYS + ADN 0 AHCYL1
    HCYS + MTHF -> THF + MET 0 MTR
    SER + HCYS -> LLCT + H2O 0 CBS
    LLCT + H2O -> CYS + HSER 0 CTH1
    OBUT + NH3 <-> HSER 0 CTH2
    CYS + O2 <-> CYSS 0 CDO1
    CYSS + AKG <-> GLU + SPYR 0 CYSAT
    SPYR + H2O -> H2SO3 + PYR 0 SPTB
    LYS + NADPH + AKG -> NADP + H2O + SAC 0 LKR1
    SAC + H2O + NAD -> GLU + NADH + AASA 0 LKR2
    AASA + NAD -> NADH + AADP 0 2ASD
    AADP + AKG -> GLU + KADP 0 LOC5
    TRP + O2 -> FKYN 0 TDO2
    FKYN + H2O -> FOR + KYN 0 KYNF
    KYN + NADPH + O2 -> HKYN + NADP + H2O 0 KMO
    HKYN + H2O -> HAN + ALA 0 KYNU2
    HAN + O2 -> CMUSA 0 HAAO
    CMUSA -> CO2 + AM6SA 0 ACSD
    AM6SA -> PIC 0 SPTA
    AM6SA + NAD -> AMUCO + NADH 0 AMSD
    AMUCO + NADPH -> KADP + NADP + NH4 0 2AMR
    ARG -> ORN + UREA 0 ARG2
    ORN + Hm -> ORNm 0 ORNMT
    ORN + Hm + CITRm <-> CITR + ORNm 0 ORNCITT
    ORNm + CAPm -> CITRm + PIm + Hm 0 OTC
    CITR + ASP + ATP <-> AMP + PPI + ARGSUCC 0 ASS
    ARGSUCC -> FUM + ARG 0 ASL
    PRO + FAD -> P5C + FADH2 0 PRODH
    P5C + NADPH -> PRO + NADP 0 PYCR1
    THR -> NH3 + H2O + OBUT 0 WTDH
    THR + NAD -> CO2 + NADH + AMA 0 TDH
    AMA + H2O + FAD -> NH3 + FADH2 + MTHGXL 0 MAOA
    GLYm + THFm + NADm <-> METTHFm + NADHm + CO2m + NH3m 0 AMT
    PHE + THBP + O2 -> TYR + DHBP + H2O 0 PAH
    NADPH + DHBP -> NADP + THBP 0 QDPR
    AKG + TYR -> HPHPYR + GLU 0 TAT
    HPHPYR + O2 -> HGTS + CO2 0 HPD
    HGTS + O2 -> MACA 0 HGD
    MACA -> FACA 0 GSTZ1
    FACA + H2O -> FUM + ACA 0 FAH
    AKG + ILE -> OMVAL + GLU 0 BCAT1A
    OMVALm + COAm + NADm -> MBCOAm + NADHm + CO2m 0 BCKDHAA
    MBCOAm + FADm -> MCCOAm + FADH2m 0 ACADMA
    MCCOAm + H2Om -> MHVCOAm 0 ECHS1B
    MHVCOAm + NADm -> MAACOAm + NADHm 0 EHHADHA
    MAACOAm -> ACCOAm + PROPCOAm 0 ACAA2
    2 ACCOAm <-> COAm + AACCOAm 0 ACATm1
    AKG + VAL -> OIVAL + GLU 0 BCAT1B
    OIVALm + COAm + NADm -> IBCOAm + NADHm + CO2m 0 BCKDHAB
    IBCOAm + FADm -> MACOAm + FADH2m 0 ACADSB
    MACOAm + H2Om -> HIBCOAm 0 EHHADHC
    HIBCOAm + H2Om -> HIBm + COAm 0 HIBCHA
    HIBm + NADm -> MMAm + NADHm 0 EHHADHB
    MMAm + COAm + NADm -> NADHm + CO2m + PROPCOAm 0 MMSDH
    PROPCOAm + CO2m + ATPm -> ADPm + PIm + DMMCOAm 0 PCCA
    DMMCOAm -> LMMCOAm 0 HIBCHF
    LMMCOAm -> SUCCOAm 0 MUT
    AKG + LEU -> OICAP + GLU 0 BCAT1C
    OICAPm + COAm + NADm -> IVCOAm + NADHm + CO2m 0 BCKDHAC
    OICAPm + COAm + NADH -> IVCOAm + NADHm + CO2m 0 BCKDHBC
    OICAPm + COAm + NADHm -> IVCOAm + NADHm + CO2m 0 DBTC
    IVCOAm + FADm -> MCRCOAm + FADH2m 0 IVD
    MCRCOAm + ATPm + CO2m + H2Om -> MGCOAm + ADPm + PIm 0 MCCC1
    MGCOAm + H2Om -> H3MCOAm 0 HIBCHB
    H3MCOAm -> ACCOAm + ACTACm 0 HMGCL
    MYOACT + ATP -> MYOATP + ACTIN 0 MYOSA
    MYOATP + ACTIN -> MYOADPAC 0 MYOSB
    MYOADPAC -> ADP + PI + MYOACT + CONTRACT 0 MYOSC
    PCRE + ADP -> CRE + ATP 0 CREATA
    AMP + H2O -> PI + ADN 0 CREATB
    ATP + AMP <-> 2 ADP 0 CREATC
    O2 <-> O2m 0 O2MT
    3HB -> 3HBm 0 HBMT
    CIT + MALm <-> CITm + MAL 0 CITMC
    PYR <-> PYRm + Hm 0 PYRMC
    C160CAR + COAm -> C160COAm + CAR 0 C160CM
    OMVAL -> OMVALm 0 HIBCHC
    OIVAL -> OIVALm 0 HIBCHD
    OICAP -> OICAPm 0 HIBCHE
    GL <-> GLm 0 GLMT
    GL3Pm + FADm -> T3P2m + FADH2m 0 GPD2
    T3P2 + NADH <-> GL3P + NAD 0 GPD1
    GL3P <-> GL3Pm 0 GL3PMC
    T3P2 <-> T3P2m 0 T3P2MC
    OAm + GLUm <-> ASPm + AKGm 0 GOT1
    OA + GLU <-> ASP + AKG 0 GOT2
    AKG + MALm <-> AKGm + MAL 0 MALMC
    ASPm + GLU + H -> Hm + GLUm + ASP 0 ASPMC
    GLCxt -> GLC 0 GLUT4
    O2xt -> O2 0 O2UP
    C160Axt + FABP -> C160FP + ALBxt 0 FAT1
    C160FP -> C160 + FABP 0 FAT2
    C180Axt + FABP -> C180FP + ALBxt 0 FAT3
    C180FP -> C180 + FABP 0 FAT4
    C161Axt + FABP -> C161FP + ALBxt 0 FAT5
    C161FP -> C161 + FABP 0 FAT6
    C181Axt + FABP -> C181FP + ALBxt 0 FAT7
    C181FP -> C181 + FABP 0 FAT8
    C182Axt + FABP -> C182FP + ALBxt 0 FAT9
    C182FP -> C182 + FABP 0 FAT10
    C204Axt + FABP -> C204FP + ALBxt 0 FAT11
    C204FP -> C204 + FABP 0 FAT12
    PYRxt + HEXT <-> PYR + H 0 PYRUP
    LACxt + HEXT <-> LAC + HEXT 0 LACUP
    H <-> HEXT 0 HextUP
    CO2 <-> CO2m 0 CO2MT
    H2O <-> H2Om 0 H2OMT
    ATP + AC + COA -> AMP + PPI + ACCOA 0 FLJ2
    C160CAR <-> C160CARm 0 C160MT
    CARm <-> CAR 0 CARMT
    CO2xt <-> CO2 0 CO2UP
    H2Oxt <-> H2O 0 H2OUP
    PIxt + HEXT <-> HEXT + PI 0 PIUP
    <-> GLCxt 0 GLCexR
    <-> PYRxt 0 PYRexR
    <-> CO2xt 0 CO2exR
    <-> O2xt 0 O2exR
    <-> PIxt 0 PlexR
    <-> H2Oxt 0 H2OexR
    <-> LACxt 0 LACexR
    <-> C160Axt 0 C160AexR
    <-> C161Axt 0 C161AexR
    <-> C180Axt 0 C180AexR
    <-> C181Axt 0 C181AexR
    <-> C182Axt 0 C182AexR
    <-> C204Axt 0 C204AexR
    <-> ALBxt 0 ALBexR
    <-> 3HB 0 HBexR
    <-> GLYCOGEN 0 GLYex
    <-> PCRE 0 PCREex
    <-> TAGLYm 0 TAGmex
    <-> ILE 0 ILEex
    <-> VAL 0 VALex
    <-> CRE 0 CREex
    <-> ADN 0 ADNex
    <-> PI 0 PIex
  • TABLE 5
    Human Cell Types
    Keratinizing epithelial cells
      Epidermal keratinocyte (differentiating epidermal cell)
      Epidermal basal cell (stem cell)
      Keratinocyte of fingernails and toenails
      Nail bed basal cell (stem cell)
      Medullary hair shaft cell
      Cortical hair shaft cell
      Cuticular hair shaft cell
      Cuticular hair root sheath cell
      Hair root sheath cell of Huxley's layer
      Hair root sheath cell of Henle's layer
      External hair root sheath cell
      Hair matrix cell (stem cell)
    Wet stratified barrier epithelial cells
      Surface epithelial cell of stratified squamous epithelium of cornea, tongue, oral cavity,
      esophagus, anal canal, distal urethra and vagina
      basal cell (stem cell) of epithelia of cornea, tongue, oral cavity, esophagus, anal canal, distal
      urethra and vagina
      Urinary epithelium cell (lining urinary bladder and urinary ducts)
    Exocrine secretory epithelial cells
      Salivary gland mucous cell (polysaccharide-rich secretion)
      Salivary gland serous cell (glycoprotein enzyme-rich secretion)
      Von Ebner's gland cell in tongue (washes taste buds)
      Mammary gland cell (milk secretion)
      Lacrimal gland cell (tear secretion)
      Ceruminous gland cell in ear (wax secretion)
      Eccrine sweat gland dark cell (glycoprotein secretion)
      Eccrine sweat gland clear cell (small molecule secretion)
      Apocrine sweat gland cell (odoriferous secretion, sex-hormone sensitive)
      Gland of Moll cell in eyelid (specialized sweat gland)
      Sebaceous gland cell (lipid-rich sebum secretion)
      Bowman's gland cell in nose (washes olfactory epithelium)
      Brunner's gland cell in duodenum (enzymes and alkaline mucus)
      Seminal vesicle cell (secretes seminal fluid components, including fructose for swimming
      sperm)
      Prostate gland cell (secretes seminal fluid components)
      Bulbourethral gland cell (mucus secretion)
      Bartholin's gland cell (vaginal lubricant secretion)
      Gland of Littre cell (mucus secretion)
      Uterus endometrium cell (carbohydrate secretion)
      Isolated goblet cell of respiratory and digestive tracts (mucus secretion)
      Stomach lining mucous cell (mucus secretion)
      Gastric gland zymogenic cell (pepsinogen secretion)
      Gastric gland oxyntic cell (hydrogen chloride secretion)
      Pancreatic acinar cell (bicarbonate and digestive enzyme secretion)
      Paneth cell of small intestine (lysozyme secretion)
      Type II pneumocyte of lung (surfactant secretion)
      Clara cell of lung
    Hormone secreting cells
      Anterior pituitary cells
      Somatotropes
      Lactotropes
      Thyrotropes
      Gonadotropes
      Corticotropes
      Intermediate pituitary cell, secreting melanocyte-stimulating hormone
      Magnocellular neurosecretory cells
      secreting oxytocin
      secreting vasopressin
      Gut and respiratory tract cells secreting serotonin
      secreting endorphin
      secreting somatostatin
      secreting gastrin
      secreting secretin
      secreting cholecystokinin
      secreting insulin
      secreting glucagon
      secreting bombesin
      Thyroid gland cells
      thyroid epithelial cell
      parafollicular cell
      Parathyroid gland cells
      Parathyroid chief cell
      oxyphil cell
      Adrenal gland cells
      chromaffin cells
      secreting steroid hormones (mineralcorticoids and gluco corticoids)
      Leydig cell of testes secreting testosterone
      Theca interna cell of ovarian follicle secreting estrogen
      Corpus luteum cell of ruptured ovarian follicle secreting progesterone
      Kidney juxtaglomerular apparatus cell (renin secretion)
      Macula densa cell of kidney
      Peripolar cell of kidney
      Mesangial cell of kidney
    Epithelial absorptive cells (Gut, Exocrine Glands and Urogenital Tract)
      Intestinal brush border cell (with microvilli)
      Exocrine gland striated duct cell
      Gall bladder epithelial cell
      Kidney proximal tubule brush border cell
      Kidney distal tubule cell
      Ductulus efferens nonciliated cell
      Epididymal principal cell
      Epididymal basal cell
    Metabolism and storage cells
      Hepatocyte (liver cell)
      White fat cell
      Brown fat cell
      Liver lipocyte
    Barrier function cells (Lung, Gut, Exocrine Glands and Urogenital Tract)
      Type I pneumocyte (lining air space of lung)
      Pancreatic duct cell (centroacinar cell)
      Nonstriated duct cell (of sweat gland, salivary gland, mammary gland, etc.)
      Kidney glomerulus parietal cell
      Kidney glomerulus podocyte
      Loop of Henle thin segment cell (in kidney)
      Kidney collecting duct cell
      Duct cell (of seminal vesicle, prostate gland, etc.)
    Epithelial cells lining closed internal body cavities
      Blood vessel and lymphatic vascular endothelial fenestrated cell
      Blood vessel and lymphatic vascular endothelial continuous cell
      Blood vessel and lymphatic vascular endothelial splenic cell
      Synovial cell (lining joint cavities, hyaluronic acid secretion)
      Serosal cell (lining peritoneal, pleural, and pericardial cavities)
      Squamous cell (lining perilymphatic space of ear)
      Squamous cell (lining endolymphatic space of ear)
      Columnar cell of endolymphatic sac with microvilli (lining endolymphatic space of ear)
      Columnar cell of endolymphatic sac without microvilli (lining endolymphatic space of ear)
      Dark cell (lining endolymphatic space of ear)
      Vestibular membrane cell (lining endolymphatic space of ear)
      Stria vascularis basal cell (lining endolymphatic space of ear)
      Stria vascularis marginal cell (lining endolymphatic space of ear)
      Cell of Claudius (lining endolymphatic space of ear)
      Cell of Boettcher (lining endolymphatic space of ear)
      Choroid plexus cell (cerebrospinal fluid secretion)
      Pia-arachnoid squamous cell
      Pigmented ciliary epithelium cell of eye
      Nonpigmented ciliary epithelium cell of eye
      Corneal endothelial cell
    Ciliated cells with propulsive function
      Respiratory tract ciliated cell
      Oviduct ciliated cell (in female)
      Uterine endometrial ciliated cell (in female)
      Rete testis cilated cell (in male)
      Ductulus efferens ciliated cell (in male)
      Ciliated ependymal cell of central nervous system (lining brain cavities)
    Extracellular matrix secretion cells
      Ameloblast epithelial cell (tooth enamel secretion)
      Planum semilunatum epithelial cell of vestibular apparatus of ear (proteoglycan secretion)
      Organ of Corti interdental epithelial cell (secreting tectorial membrane covering hair cells)
      Loose connective tissue fibroblasts
      Corneal fibroblasts
      Tendon fibroblasts
      Bone marrow reticular tissue fibroblasts
      Other nonepithelial fibroblasts
      Blood capillary pericyte
      Nucleus pulposus cell of intervertebral disc
      Cementoblast/cementocyte (tooth root bonelike cementum secretion)
      Odontoblast/odontocyte (tooth dentin secretion)
      Hyaline cartilage chondrocyte
      Fibrocartilage chondrocyte
      Elastic cartilage chondrocyte
      Osteoblast/osteocyte
      Osteoprogenitor cell (stem cell of osteoblasts)
      Hyalocyte of vitreous body of eye
      Stellate cell of perilymphatic space of ear
    Contractile cells
      Red skeletal muscle cell (slow)
      White skeletal muscle cell (fast)
      Intermediate skeletal muscle cell
      nuclear bag cell of Muscle spindle
      nuclear chain cell of Muscle spindle
      Satellite cell (stem cell)
      Ordinary heart muscle cell
      Nodal heart muscle cell
      Purkinje fiber cell
      Smooth muscle cell (various types)
      Myoepithelial cell of iris
      Myoepithelial cell of exocrine glands
      Red Blood Cell
    Blood and immune system cells
      Erythrocyte (red blood cell)
      Megakaryocyte (platelet precursor)
      Monocyte
      Connective tissue macrophage (various types)
      Epidermal Langerhans cell
      Osteoclast (in bone)
      Dendritic cell (in lymphoid tissues)
      Microglial cell (in central nervous system)
      Neutrophil granulocyte
      Eosinophil granulocyte
      Basophil granulocyte
      Mast cell
      Helper T cell
      Suppressor T cell
      Cytotoxic T cell
      B cells
      Natural killer cell
      Reticulocyte
      Stem cells and committed progenitors for the blood and immune system (various types)
    Sensory transducer cells
      Photoreceptor rod cell of eye
      Photoreceptor blue-sensitive cone cell of eye
      Photoreceptor green-sensitive cone cell of eye
      Photoreceptor red-sensitive cone cell of eye
      Auditory inner hair cell of organ of Corti
      Auditory outer hair cell of organ of Corti
      Type I hair cell of vestibular apparatus of ear (acceleration and gravity)
      Type II hair cell of vestibular apparatus of ear (acceleration and gravity)
      Type I taste bud cell
      Olfactory receptor neuron
      Basal cell of olfactory epithelium (stem cell for olfactory neurons)
      Type I carotid body cell (blood pH sensor)
      Type II carotid body cell (blood pH sensor)
      Merkel cell of epidermis (touch sensor)
      Touch-sensitive primary sensory neurons (various types)
      Cold-sensitive primary sensory neurons
      Heat-sensitive primary sensory neurons
      Pain-sensitive primary sensory neurons (various types)
      Proprioceptive primary sensory neurons (various types)
    Autonomic neuron cells
      Cholinergic neural cell (various types)
      Adrenergic neural cell (various types)
      Peptidergic neural cell (various types)
    Sense organ and peripheral neuron supporting cells
      Inner pillar cell of organ of Corti
      Outer pillar cell of organ of Corti
      Inner phalangeal cell of organ of Corti
      Outer phalangeal cell of organ of Corti
      Border cell of organ of Corti
      Hensen cell of organ of Corti
      Vestibular apparatus supporting cell
      Type I taste bud supporting cell
      Olfactory epithelium supporting cell
      Schwann cell
      Satellite cell (encapsulating peripheral nerve cell bodies)
      Enteric glial cell
    Central nervous system neurons and glial cells
      Neuron cells (large variety of types, still poorly classified)
      Astrocyte (various types)
      Oligodendrocyte
    Lens cells
      Anterior lens epithelial cell
      Crystallin-containing lens fiber cell
    Pigment cells
      Melanocyte
      Retinal pigmented epithelial cell
    Germ cells
      Oogonium/Oocyte
      Spermatid
      Spermatocyte
      Spermatogonium cell (stem cell for spermatocyte)
      Spermatozoon
    Nurse cells
      Ovarian follicle cell
      Sertoli cell (in testis)
      Thymus epithelial cell
  • TABLE 6
    Human Tissues
    Epithelial Tissue Connective Tissues
      Unilaminar (simple) epithelia   Fluid Connective Tissues
        Squamous     Lymph
        Cuboidal     Blood
        Columnar   Connective Tissues Proper
        Sensory     Loose Connective Tissues
        Myoepitheliocyte       Areolar
      Multilaminar eipithelia     Loose Connective Tissues and Inflammation
        Replacing or stratified squamous epithelia       Adipose
        Stratified cuboidal and columnar eipithelia       Reticular
      Urothelium (transitional epithelium)     Dense Connective Tissues
        Seminiferous eipthelium       Regular(collagen)
      Glands       Irregular(collagen)
        Exocrine glands       Regular(elastic)
          Ducts and Tubules   Supportive Connective Tissues
        Endocrine glands     Osseous Tissue
    Nervous Tissue       Compact
      Neurons       Cancellous
        Multipolar Neurons in CNS     Cartilage
      Nerves       Hyaline
        Nerves of the PNS       Elastic
      Receptors       Fibrocartilage
        Miessner's and Pacinian Corpuscles Muscle Tissue
      Non-striated
        Smooth Muscle
      Striated
        Skeletal Muscle
        Cardiac Muscle
    Systems Major Structures
    Skeletal Bones, cartilage, tendons, ligaments, and joints
    Muscular Muscles (skeletal, cardiac, and smooth)
    Integumentary Skin, hair nails, breast
    Circulatory Heart, blood vessels, blood
    Respiratory Trachea, air passages, lungs
    Immune Lymph nodes and vessels, white blood cells
    Digestive Mouth, esophagus, stomach, liver, pancreas, duodenum, jejunum, ileum,
    caecum, rectum, gallbladder, pancreas, small and large intestines
    Excretory and Urinary Kidneys, ureters, bladder, urethra
    Nervous Brain, spinal cord, nerves, sense organs, receptors, dorsal root ganglion
    Endocrine Endocrine glands, pineal gland, pituitary gland, adrenal gland, thyroid
    gland, and hormones
    Lymphatic Lymph nodes, spleen, lymph vessels
    Reproductive Ovaries, uterus, fallopian tube, mammary glands (in females), vas
    deferens, prostate, testes (in males), umbilical cord, placenta
    Functions
    provides structure; supports and protects internal organs
    provides structure; supports and moves trunk and limbs; moves
    substances through body
    protects against pathogens; helps regulate body temperature
    transports nutrients and wastes to and from all body tissues
    carries air into and out of lungs, where gases (oxygen and carbon
    dioxide) are exchanged
    provides protection against infection and disease
    stores and digests food; absorbs nutrients; eliminates waste
    eliminate waste; maintains water and chemical balance
    controls and coordinates body movements and senses; controls
    consciousness and creativity; helps monitor and maintain other body
    systems
    maintain homeostasis; regulates metabolism, water and mineral
    balance, growth and sexual development, and reproduction
    cleans and returns tissue fluid to the blood and destroys pathogens that
    enter the body
    produce gametes and offspring
  • TABLE 7
    Cells of the Liver
    Hepatocytes
    Perisinusoidal (Ito) cells
    Endotheliocytes
    Macrophages (Kupffer cells)
    Lymphocytes (pit cells)
    Cells of the biliary tree
      Cuboidal epitheliocytes
      Columnar epitheliocytes
    Connective tissue cells
  • TABLE 15
    Adipocyte-myocyte reactions
    Reaction Protein
    Abbreviation Reaction Name Equation Subsystem Classification
    G6PASEer_ac glucose-6-phosphatase [f]: g6p + h2o --> glc-D + pi Glycolysis/Gluconeogenesis EC-3.1.3.9
    G6PASEer_mc glucose-6-phosphatase [u]: g6p + h2o --> glc-D + pi Glycolysis/Gluconeogenesis EC-3.1.3.9
    PFK26_ac 6-phosphofructo-2-kinase [a]: atp + f6p --> adp + f26bp + h Glycolysis/Gluconeogenesis EC-2.7.1.105
    PGI_ac glucose-6-phosphate [a]: g6p <==> f6p Glycolysis/Gluconeogenesis EC-5.3.1.9
    isomerase
    PGK_ac phosphoglycerate kinase [a]: 13dpg + adp <==> 3pg + atp Glycolysis/Gluconeogenesis EC-2.7.2.3
    PGM_ac phosphoglycerate mutase [a]: 3pg <==> 2pg Glycolysis/Gluconeogenesis EC-5.4.2.1
    PYK_ac pyruvate kinase [a]: adp + h + pep --> atp + pyr Glycolysis/Gluconeogenesis EC-2.7.1.40
    TPI_ac triose-phosphate [a]: dhap <==> g3p Glycolysis/Gluconeogenesis EC-5.3.1.1
    isomerase
    ACONTm_ac Aconitate hydratase [b]: cit <==> icit Central Metabolism EC-4.2.1.3
    ACONTm_mc Aconitate hydratase [z]: cit <==> icit Central Metabolism EC-4.2.1.3
    AKGDm_ac 2-oxoglutarate [b]: akg + coa + nad --> co2 + Central Metabolism
    dehydrogenase, nadh + succoa
    mitochondrial
    AKGDm_mc 2-oxoglutarate [z]: akg + coa + nad --> co2 + Central Metabolism
    dehydrogenase, nadh + succoa
    mitochondrial
    CITL2_ac Citrate lyase (ATP- [a]: atp + cit + coa --> accoa + adp + Central Metabolism EC-4.1.3.8
    requiring) oaa + pi
    CITL2_mc Citrate lyase (ATP- [y]: atp + cit + coa --> accoa + adp + Central Metabolism EC-4.1.3.8
    requiring) oaa + pi
    CSm_ac citrate synthase [b]: accoa + h2o + oaa --> cit + Central Metabolism EC-4.1.3.7
    coa + h
    CSm_mc citrate synthase [z]: accoa + h2o + oaa --> cit + Central Metabolism EC-4.1.3.7
    coa + h
    ENO_ac enolase [a]: 2pg <==> h2o + pep Central Metabolism EC-4.2.1.11
    ENO_mc enolase [y]: 2pg <==> h2o + pep Central Metabolism EC-4.2.1.11
    FBA_ac fructose-bisphosphate [a]: fdp <==> dhap + g3p Central Metabolism EC-4.1.2.13
    aldolase
    FBA_mc fructose-bisphosphate [y]: fdp <==> dhap + g3p Central Metabolism EC-4.1.2.13
    aldolase
    FBP26_ac Fructose-2,6-bisphosphate [a]: f26bp + h2o --> f6p + pi Central Metabolism EC-3.1.3.46
    2-phosphatase
    FBP26_mc Fructose-2,6-bisphosphate [y]: f26bp + h2o --> f6p + pi Central Metabolism EC-3.1.3.46
    2-phosphatase
    FBP_ac fructose-bisphosphatase [a]: fdp + h2o --> f6p + pi Central Metabolism EC-3.1.3.11
    FBP_mc fructose-bisphosphatase [y]: fdp + h2o --> f6p + pi Central Metabolism EC-3.1.3.11
    FUMm_ac fumarase, mitochondrial [b]: fum + h2o <==> mal-L Central Metabolism EC-4.2.1.2
    FUMm_mc fumarase, mitochondrial [z]: fum + h2o <==> mal-L Central Metabolism EC-4.2.1.2
    G3PD1_ac glycerol-3-phosphate [a]: glyc3p + nad <==> dhap + h + Central Metabolism EC-1.1.1.94
    dehydrogenase (NAD), nadh
    adipocyte
    G3PD_mc Glycerol-3-phosphate [y]: dhap + h + nadh --> glyc3p + Central Metabolism EC-1.1.1.8
    dehydrogenase (NAD) nad
    G3PDm_ac glycerol-3-phosphate [b]: fad + glyc3p --> dhap + fadh2 Central Metabolism EC-1.1.99.5
    dehydrogenase
    G3PDm_mc glycerol-3-phosphate [z]: fad + glyc3p --> dhap + fadh2 Central Metabolism EC-1.1.99.5
    dehydrogenase
    G6PDH_ac glucose 6-phosphate [a]: g6p + nadp --> 6pgl + h + Central Metabolism EC-1.1.1.49
    dehydrogenase nadph
    G6PDH_mc glucose 6-phosphate [y]: g6p + nadp --> 6pgl + h + Central Metabolism EC-1.1.1.49
    dehydrogenase nadph
    GAPD_ac glyceraldehyde-3- [a]: g3p + nad + pi <==> 13dpg + Central Metabolism EC-1.2.1.12
    phosphate dehydrogenase h + nadh
    (NAD)
    GAPD_mc glyceraldehyde-3- [y]: g3p + nad + pi <==> 13dpg + Central Metabolism EC-1.2.1.12
    phosphate dehydrogenase h + nadh
    (NAD)
    GL3Ptm_ac glycerol-3-phosphate glyc3p[a] <==> glyc3p[b] Central Metabolism
    transport, adipocyte
    mitochondrial
    GLCP_ac glycogen phosphorylase [a]: glycogen + pi --> g1p Central Metabolism EC-2.4.1.1
    HCO3Em_ac HCO3 equilibration [b]: co2 + h2o <==> h + hco3 Central Metabolism EC-4.2.1.1
    reaction, mitochondrial
    HCO3Em_mc HCO3 equilibration [z]: co2 + h2o <==> h + hco3 Central Metabolism EC-4.2.1.1
    reaction, mitochondrial
    HEX1_ac hexokinase (D- [a]: atp + glc-D --> adp + g6p + h Central Metabolism EC-2.7.1.2
    glucose:ATP)
    HEX1_mc hexokinase (D- [y]: atp + glc-D --> adp + g6p + h Central Metabolism EC-2.7.1.2
    glucose:ATP)
    ICDHxm_ac Isocitrate dehydrogenase [b]: icit + nad --> akg + co2 + nadh Central Metabolism EC-1.1.1.41
    (NAD+)
    ICDHxm_mc Isocitrate dehydrogenase [z]: icit + nad --> akg + co2 + nadh Central Metabolism EC-1.1.1.41
    (NAD+)
    ICDHym_ac Isocitrate dehydrogenase [b]: icit + nadp --> akg + co2 + Central Metabolism EC-1.1.1.42
    (NADP+) nadph
    ICDHym_mc Isocitrate dehydrogenase [z]: icit + nadp --> akg + co2 + Central Metabolism EC-1.1.1.42
    (NADP+) nadph
    LDH_L_mc L-lactate dehydrogenase [y]: lac-L + nad <==> h + nadh + Central Metabolism EC-1.1.1.27
    pyr
    MDH_ac malate dehydrogenase [a]: mal-L + nad <==> h + nadh + Central Metabolism EC-1.1.1.37
    oaa
    MDH_mc malate dehydrogenase [y]: mal-L + nad <==> h + nadh + Central Metabolism EC-1.1.1.37
    oaa
    MDHm_ac malate dehydrogenase, [b]: mal-L + nad <==> h + nadh + Central Metabolism EC-1.1.1.37
    mitochondrial oaa
    MDHm_mc malate dehydrogenase, [z]: mal-L + nad <==> h + nadh + Central Metabolism EC-1.1.1.37
    mitochondrial oaa
    ME1m_ac malic enzyme (NAD), [b]: mal-L + nad --> co2 + nadh + Central Metabolism EC-1.1.1.38
    mitochondrial pyr
    ME1m_mc malic enzyme (NAD), [z]: mal-L + nad --> co2 + nadh + Central Metabolism EC-1.1.1.38
    mitochondrial pyr
    ME2_ac malic enzyme (NADP) [a]: mal-L + nadp --> co2 + nadph + Central Metabolism EC-1.1.1.40
    pyr
    ME2_mc malic enzyme (NADP) [y]: mal-L + nadp --> co2 + nadph + Central Metabolism EC-1.1.1.40
    pyr
    ME2m_ac malic enzyme (NADP), [b]: mal-L + nadp --> co2 + nadph + Central Metabolism EC-1.1.1.40
    mitochondrial pyr
    ME2m_mc malic enzyme (NADP), [z]: mal-L + nadp --> co2 + nadph + Central Metabolism EC-1.1.1.40
    mitochondrial pyr
    PCm_mc pyruvate carboxylase, [z]: atp + hco3 + pyr --> adp + h + Central Metabolism EC-6.4.1.1
    mitochondrial oaa + pi
    PDHm_mc pyruvate dehydrogenase, [z]: coa + nad + pyr --> accoa + Central Metabolism EC-1.2.1.51
    mitochondrial co2 + nadh
    PFK26_mc 6-phosphofructo-2-kinase [y]: atp + f6p --> adp + f26bp + h Central Metabolism EC-2.7.1.105
    PFK_ac phosphofructokinase [a]: atp + f6p --> adp + fdp + h Central Metabolism EC-2.7.1.11
    PFK_mc phosphofructokinase [y]: atp + f6p --> adp + fdp + h Central Metabolism EC-2.7.1.11
    PGDH_mc phosphogluconate [y]: 6pgc + nadp --> co2 + nadph + Central Metabolism EC-1.1.1.44
    dehydrogenase ru5p-D
    PGI_mc glucose-6-phosphate [y]: g6p <==> f6p Central Metabolism EC-5.3.1.9
    isomerase
    PGK_mc phosphoglycerate kinase [y]: 13dpg + adp <==> 3pg + atp Central Metabolism EC-2.7.2.3
    PGL_mc 6- [y]: 6pgl + h2o --> 6pgc + h Central Metabolism EC-3.1.1.31
    phosphogluconolactonase
    PGM_mc phosphoglycerate mutase [y]: 3pg <==> 2pg Central Metabolism EC-5.4.2.1
    PPA_ac inorganic diphosphatase [a]: h2o + ppi --> h + (2) pi Central Metabolism EC-3.6.1.1
    PPA_mc inorganic diphosphatase [y]: h2o + ppi --> h + (2) pi Central Metabolism EC-3.6.1.1
    PPCKG_ac phosphoenolpyruvate [a]: gtp + oaa --> co2 + gdp + pep Central Metabolism EC-4.1.1.32
    carboxykinase (GTP)
    PPCKG_mc phosphoenolpyruvate [y]: gtp + oaa --> co2 + gdp + pep Central Metabolism EC-4.1.1.32
    carboxykinase (GTP)
    PYK_mc pyruvate kinase [y]: adp + h + pep --> atp + pyr Central Metabolism EC-2.7.1.40
    RPE_mc ribulose 5-phosphate 3- [y]: ru5p-D <==> xu5p-D Central Metabolism EC-5.1.3.1
    epimerase
    RPI_mc ribose-5-phosphate [y]: r5p <==> ru5p-D Central Metabolism EC-5.3.1.6
    isomerase
    SUCD1m_mc succinate dehydrogenase [z]: succ + ubq <==> fum + qh2 Central Metabolism EC-1.3.5.1
    SUCD3m_mc succinate dehydrogenase [z]: fadh2 + ubq <==> fad + qh2 Central Metabolism
    cytochrome b
    SUCOASAm_mc Succinate--CoA ligase [z]: atp + coa + succ <==> adp + Central Metabolism EC-6.2.1.4
    (ADP-forming) pi + succoa
    SUCOASGm_mc Succinate--CoA ligase [z]: coa + gtp + succ <==> gdp + Central Metabolism EC-6.2.1.4
    (GDP-forming) pi + succoa
    TAL_mc transaldolase [y]: g3p + s7p <==> e4p + f6p Central Metabolism EC-2.2.1.2
    TKT1_mc transketolase [y]: r5p + xu5p-D <==> g3p + s7p Central Metabolism EC-2.2.1.1
    TKT2_mc transketolase [y]: e4p + xu5p-D <==> f6p + g3p Central Metabolism EC-2.2.1.1
    TPI_mc triose-phosphate [y]: dhap <==> g3p Central Metabolism EC-5.3.1.1
    isomerase
    SUCOASAm_ac Succinate--CoA ligase [b]: atp + coa + succ <==> adp + Citrate Cycle (TCA) EC-6.2.1.4
    (ADP-forming) pi + succoa
    SUCOASGm_ac Succinate--CoA ligase [b]: coa + gtp + succ <==> gdp + Citrate Cycle (TCA) EC-6.2.1.4
    (GDP-forming) pi + succoa
    PGDH_ac phosphogluconate [a]: 6pgc + nadp --> co2 + nadph + Pentose Phosphate EC-1.1.1.44
    dehydrogenase ru5p-D Cycle
    PGL_ac 6- [a]: 6pgl + h2o --> 6pgc + h Pentose Phosphate EC-3.1.1.31
    phosphogluconolactonase Cycle
    RPE_ac ribulose 5-phosphate 3- [a]: ru5p-D <==> xu5p-D Pentose Phosphate EC-5.1.3.1
    epimerase Cycle
    RPI_ac ribose-5-phosphate [a]: r5p <==> ru5p-D Pentose Phosphate EC-5.3.1.6
    isomerase Cycle
    TAL_ac transaldolase [a]: g3p + s7p <==> e4p + f6p Pentose Phosphate EC-2.2.1.2
    Cycle
    TKT1_ac transketolase [a]: r5p + xu5p-D <==> g3p + s7p Pentose Phosphate EC-2.2.1.1
    Cycle
    TKT2_ac transketolase [a]: e4p + xu5p-D <==> f6p + g3p Pentose Phosphate EC-2.2.1.1
    Cycle
    PCm_ac pyruvate carboxylase, [b]: atp + hco3 + pyr --> adp + h + Pyruvate metabolism EC-6.4.1.1
    mitochondrial oaa + pi
    PDHm_ac pyruvate dehydrogenase, [b]: coa + nad + pyr --> accoa + Pyruvate metabolism EC-1.2.1.51
    mitochondrial co2 + nadh
    ATPM_ac ATP maintenance [a]: atp + h2o --> adp + h + pi Energy Metabolism
    requirment
    ATPM_mc ATP maintenance [y]: atp + h2o --> adp + h + pi Energy Metabolism
    requirment
    ATPS4m_ac ATP synthase, adipocyte adp[b] + (4) h[a] + pi[b] --> atp[b] + Energy Metabolism EC-3.6.1.14,
    mitochondrial (3) h[b] + h2o[b]
    ATPS4m_mc ATP synthase, myocyte adp[z] + (4) h[y] + pi[z] --> atp[z] + Energy Metabolism EC-3.6.1.14,
    mitochondrial (3) h[z] + h2o[y]
    ATPSis_ac ATPase, adipocyte atp[a] + h2o[a] --> adp[a] + h[i] + Energy Metabolism EC-3.6.3.6,
    cytosolic pi[a]
    ATPSis_mc ATPase, myocyte atp[y] + h2o[y] --> adp[y] + h[c] + Energy Metabolism EC-3.6.3.6,
    cytosolic pi[y]
    CREATK_mc creatine kinase, myocyte [y]: atp + creat <==> adp + creatp Energy Metabolism EC-2.7.3.2
    cytosol
    CREATPD_mc creatine phosphate [y]: creatp --> crtn + h + pi Energy Metabolism
    dephosphorylation,
    spontaneous
    CYOO4m_ac cytochrome c oxidase (4) focytc[b] + (8) h[b] + o2[b] --> Energy Metabolism EC-1.9.3.1,
    (adipocyte mitochondrial 4 (4) ficytc[b] + (4) h[a] + (2) h2o[b]
    protons)
    CYOO4m_mc cytochrome c oxidase (4) focytc[z] + (8) h[z] + o2[z] --> Energy Metabolism EC-1.9.3.1,
    (myocyte mitochondrial 4 (4) ficytc[z] + (4) h[y] + (2) h2o[z]
    protons)
    CYOR4m_ac ubiquinol cytochrome c (2) ficytc[b] + (2) h[b] + qh2[b] --> Energy Metabolism EC-1.10.2.2,
    reductase, adipocyte (2) focytc[b] + (4) h[a] + ubq[b]
    CYOR4m_mc ubiquinol cytochrome c (2) ficytc[z] + (2) h[z] + qh2[z] --> Energy Metabolism EC-1.10.2.2,
    reductase, myocyte (2) focytc[z] + (4) h[y] + ubq[z]
    NADH4m_mc NADH dehydrogenase, (5) h[z] + nadh[z] + ubq[z] --> (4) Energy Metabolism EC-1.6.99.3,
    mitochondrial h[y] + nad[z] + qh2[z]
    NADH4m_ac NADH dehydrogenase, (5) h[b] + nadh[b] + ubq[b] --> (4) Oxidative EC-1.6.99.3,
    adipocyte mitochondrial h[a] + nad[b] + qh2[b] phosphorylation
    SUCD1m_ac succinate dehydrogenase [b]: succ + ubq <==> fum + qh2 Oxidative EC-1.3.5.1
    phosphorylation
    SUCD3m_ac succinate dehydrogenase [b]: fadh2 + ubq <==> fad + qh2 Oxidative
    cytochrome b phosphorylation
    GALUi_ac UTP-glucose-1-phosphate [a]: g1p + h + utp --> ppi + udpg Galactose metabolism EC-2.7.7.9
    uridylyltransferase
    (irreversible)
    PGMT_ac phosphoglucomutase [a]: g1p <==> g6p Galactose metabolism EC-5.4.2.2
    GALUi_mc UTP-glucose-1-phosphate [y]: g1p + h + utp --> ppi + udpg Carbohydrate EC-2.7.7.9
    uridylyltransferase Metabolism
    (irreversible)
    GLCP_mc glycogen phosphorylase [y]: glycogen + pi --> g1p Carbohydrate EC-2.4.1.1
    Metabolism
    GLYGS_ac glycogen synthase [a]: udpg --> glycogen + h + udp Carbohydrate EC-2.4.1.11
    (UDPGlc) Metabolism
    GLYGS_mc glycogen synthase [y]: udpg --> glycogen + h + udp Carbohydrate EC-2.4.1.11
    (UDPGlc) Metabolism
    PGMT_mc phosphoglucomutase [y]: g1p <==> g6p Carbohydrate EC-5.4.2.2
    Metabolism
    ACACT10m_ac acetyl-CoA C- [b]: 2maacoa + coa --> accoa + Amino Acid Metabolism EC-2.3.1.16
    acyltransferase, adipocyte ppcoa
    mitochondrial
    ACOAD3m_ac acyl-CoA dehydrogenase, [b]: 2mbcoa + fad <==> 2mb2coa + Amino Acid Metabolism EC-1.3.99.3
    adipocyte mitochondrial fadh2
    ASPO_D_ac D-aspartate oxidase [a]: asp-D + h2o + o2 --> h + h2o2 + Amino Acid Metabolism EC-1.4.3.16
    nh3 + oaa
    ASPR_ac aspartase racemase, [a]: asp-D <==> asp-L Amino Acid Metabolism EC-5.1.1.13
    adipocyte cytosolic
    ASPTA1_ac aspartate transaminase [a]: akg + asp-L <==> glu-L + oaa Amino Acid Metabolism EC-2.6.1.1
    ASPTA1_mc aspartate transaminase [y]: akg + asp-L <==> glu-L + oaa Amino Acid Metabolism EC-2.6.1.1
    ASPTA1m_ac aspartate transaminase, [b]: akg + asp-L <==> glu-L + oaa Amino Acid Metabolism EC-2.6.1.1
    mitochondrial
    ASPTA1m_mc aspartate transaminase, [z]: akg + asp-L <==> glu-L + oaa Amino Acid Metabolism EC-2.6.1.1
    mitochondrial
    ECOAH3m_ac enoyl-CoA hydratase, [b]: 2mb2coa + h2o <==> Amino Acid Metabolism EC-4.2.1.17
    adipocyte mitochondrial 3hmbcoa
    HACD8m_ac 3-hydroxyacyl-CoA [b]: 3hmbcoa + nad <==> Amino Acid Metabolism EC-1.1.1.35
    dehydrogenase (2- 2maacoa + h + nadh
    Methylacetoacetyl-CoA),
    adipocyte mitochondrial
    ILETA_ac isoleucine transaminase, [a]: akg + ile-L <==> 3mop + glu-L Amino Acid Metabolism EC-2.6.1.42
    adipocyte cytosolic
    MOBD3m_ac 3-Methyl-2-oxobutanoate [b]: 3mop + coa + nad --> 2mbcoa + Amino Acid Metabolism
    dehydrogenase, adipocyte co2 + nadh
    mitochondrial
    CSNAT_mc carnitine O- [y]: accoa + crn --> acrn + coa Carnitine Shuttle EC-2.3.1.7
    acetyltransferase, myocyte
    cytosol
    CSNATifm_mc carnitine O- [z]: acrn + coa --> accoa + crn Carnitine Shuttle EC-2.3.1.7
    aceyltransferase, forward
    reaction, myocyte
    mitochondrial
    PPS_ac propionyl-CoA synthetase, [a]: atp + coa + ppa <==> amp + Propanoate EC-6.2.1.1
    adipocyte cytosolic ppcoa + ppi Metabolism
    PPSm_ac propionyl-CoA synthetase, [b]: atp + coa + ppa <==> amp + Propanoate EC-6.2.1.1
    adipocyte mitochondrial ppcoa + ppi Metabolism
    ACACT10m_mc acetyl-CoA C- [z]: accoa + occoa <==> 3odcoa + Fatty Acid Degradation EC-2.3.1.16
    acyltransferase (octanoyl- coa
    CoA)
    ACACT11m_mc acetyl-CoA C- [z]: accoa + nncoa <==> 3oedcoa + Fatty Acid Degradation EC-2.3.1.16
    acyltransferase (nonanoyl- coa
    CoA)
    ACACT12m_mc acetyl-CoA C- [z]: accoa + dccoa <==> 3oddcoa + Fatty Acid Degradation EC-2.3.1.16
    acyltransferase (decanoyl- coa
    CoA)
    ACACT13m_mc acetyl-CoA C- [z]: accoa + edcoa <==> 3otrdcoa + Fatty Acid Degradation EC-2.3.1.16
    acyltransferase coa
    (endecanoyl-CoA)
    ACACT145m_mc acetyl-CoA C- [z]: accoa + cis-dd2coa <==> Fatty Acid Degradation EC-2.3.1.16
    acyltransferase 3otdecoa5 + coa
    (dodecenoyl-CoA
    C12:1CoA, n-3)
    ACACT14m_mc acetyl-CoA C- [z]: accoa + ddcoa <==> 3otdcoa + Fatty Acid Degradation EC-2.3.1.16
    acyltransferase coa
    (dodecanoyl-CoA)
    ACACT15m_mc acetyl-CoA C- [z]: accoa + trdcoa <==> 3opdcoa + Fatty Acid Degradation EC-2.3.1.16
    acyltransferase coa
    (tridecanoyl-CoA)
    ACACT167m_mc acetyl-CoA C- [z]: accoa + tdecoa5 <==> Fatty Acid Degradation EC-2.3.1.16
    acyltransferase 3ohdecoa7 + coa
    (tetradecenoyl-CoA
    C14:1CoA, n-5)
    ACACT16m_mc acetyl-CoA C- [z]: accoa + tdcoa <==> 3ohdcoa + Fatty Acid Degradation EC-2.3.1.16
    acyltransferase coa
    (tetradecanoyl-CoA)
    ACACT189m_mc acetyl-CoA C- [z]: accoa + hdcoa7 <==> Fatty Acid Degradation EC-2.3.1.16
    acyltransferase 3oodcecoa9 + coa
    (hexadecenoyl-CoA
    C16:1CoA, n-7)
    ACACT18m_mc acetyl-CoA C- [z]: accoa + pmtcoa <==> Fatty Acid Degradation EC-2.3.1.16
    acyltransferase (palmitoyl- 3oodcoa + coa
    CoA C16:0CoA)
    ACACT20m_mc acetyl-CoA C- [z]: accoa + strcoa <==> 3oescoa + Fatty Acid Degradation EC-2.3.1.16
    acyltransferase coa
    (octadecanoyl-CoA
    C18:0CoA)
    ACACT22p_mc acetyl-CoA C- [w]: accoa + ecsacoa <==> Fatty Acid Degradation EC-2.3.1.16
    acyltransferase 3odscoa + coa
    (eicosanoyl-CoA
    C20:0CoA)
    ACACT4m_mc acetyl-CoA C- [z]: (2) accoa <==> aacoa + coa Fatty Acid Degradation EC-2.3.1.16
    acyltransferase (acetyl-
    CoA)
    ACACT5m_mc acetyl-CoA C- [z]: accoa + ppcoa <==> 3optcoa + Fatty Acid Degradation EC-2.3.1.16
    acyltransferase (propanoyl- coa
    CoA)
    ACACT6m_mc acetyl-CoA C- [z]: accoa + btcoa <==> 3ohcoa + Fatty Acid Degradation EC-2.3.1.16
    acyltransferase (butanoyl- coa
    CoA)
    ACACT7m_mc acetyl-CoA C- [z]: accoa + ptcoa <==> 3ohpcoa + Fatty Acid Degradation EC-2.3.1.16
    acyltransferase (pentanoyl- coa
    CoA)
    ACACT8m_mc acetyl-CoA C- [z]: accoa + hxcoa <==> 3oocoa + Fatty Acid Degradation EC-2.3.1.16
    acyltransferase (hexanoyl- coa
    CoA)
    ACACT9m_mc acetyl-CoA C- [z]: accoa + hpcoa <==> 3onncoa + Fatty Acid Degradation EC-2.3.1.16
    acyltransferase (heptanoyl- coa
    CoA)
    ACOAD10m_mc acyl-CoA dehydrogenase [z]: dccoa + fad <==> dc2coa + Fatty Acid Degradation EC-1.3.99.13
    (decanoyl-CoA C10:0CoA) fadh2
    ACOAD11m_mc acyl-CoA dehydrogenase [z]: edcoa + fad <==> ed2coa + Fatty Acid Degradation EC-1.3.99.13
    (endecanoyl-CoA) fadh2
    ACOAD12m_mc acyl-CoA dehydrogenase [z]: ddcoa + fad <==> fadh2 + Fatty Acid Degradation EC-1.3.99.13
    (dodecanoyl-CoA trans-dd2coa
    C12:0CoA)
    ACOAD13m_mc acyl-CoA dehydrogenase [z]: fad + trdcoa <==> fadh2 + Fatty Acid Degradation EC-1.3.99.13
    (tridecanoyl-CoA) trd2coa
    ACOAD145m_mc acyl-CoA dehydrogenase [z]: fad + tdecoa5 <==> fadh2 + Fatty Acid Degradation EC-1.3.99.13
    (tetradecenoyl-CoA, tde2coa5
    C14:1CoA, n-5)
    ACOAD14m_mc acyl-CoA dehydrogenase [z]: fad + tdcoa <==> fadh2 + Fatty Acid Degradation EC-1.3.99.13
    (tetradecanoyl-CoA) td2coa
    ACOAD15m_mc acyl-CoA dehydrogenase [z]: fad + pdcoa <==> fadh2 + Fatty Acid Degradation EC-1.3.99.13
    (pentadecanoyl-CoA) pd2coa
    ACOAD167m_mc acyl-CoA dehydrogenase [z]: fad + hdcoa7 <==> fadh2 + Fatty Acid Degradation EC-1.3.99.13
    (hexadecenoyl-CoA, hde2coa7
    C16:1CoA, n-7)
    ACOAD16m_mc acyl-CoA dehydrogenase [z]: fad + pmtcoa <==> fadh2 + Fatty Acid Degradation EC-1.3.99.13
    (hexadecanoyl-CoA hdd2coa
    C16:0CoA)
    ACOAD189m_mc acyl-CoA dehydrogenase [z]: fad + odecoa9 <==> fadh2 + Fatty Acid Degradation EC-1.3.99.13
    (octadecenoyl-CoA, ode2coa9
    C18:1CoA, n-9)
    ACOAD18m_mc acyl-CoA dehydrogenase [z]: fad + strcoa <==> fadh2 + Fatty Acid Degradation EC-1.3.99.13
    (Stearyl-CoA, C18:0CoA) od2coa
    ACOAD20m_mc acyl-CoA dehydrogenase [z]: ecsacoa + fad <==> es2coa + Fatty Acid Degradation EC-1.3.99.13
    (eicosanoyl-CoA, fadh2
    C20:0CoA)
    ACOAD22p_mc acyl-CoA dehydrogenase [w]: dcsacoa + fad <==> ds2coa + Fatty Acid Degradation EC-1.3.99.13
    (docosanoyl-CoA, fadh2
    C22:0CoA)
    ACOAD4m_mc acyl-CoA dehydrogenase [z]: btcoa + fad <==> b2coa + Fatty Acid Degradation EC-1.3.99.13
    (butanoyl-CoA C4:0CoA) fadh2
    ACOAD5m_mc acyl-CoA dehydrogenase [z]: fad + ptcoa <==> fadh2 + Fatty Acid Degradation EC-1.3.99.13
    (pentanoyl-CoA) pt2coa
    ACOAD6m_mc acyl-CoA dehydrogenase [z]: fad + hxcoa <==> fadh2 + Fatty Acid Degradation EC-1.3.99.13
    (hexanoyl-CoA C8:0CoA) hx2coa
    ACOAD7m_mc acyl-CoA dehydrogenase [z]: fad + hpcoa <==> fadh2 + Fatty Acid Degradation EC-1.3.99.13
    (heptanoyl-CoA) hp2coa
    ACOAD8m_mc acyl-CoA dehydrogenase [z]: fad + occoa <==> fadh2 + Fatty Acid Degradation EC-1.3.99.13
    (octanoyl-CoA C8:0CoA) oc2coa
    ACOAD9m_mc acyl-CoA dehydrogenase [z]: fad + nncoa <==> fadh2 + Fatty Acid Degradation EC-1.3.99.13
    (nonanoyl-CoA) nn2coa
    CRNDST_mc carnitine [y]: crn + dcsacoa --> coa + Fatty Acid Degradation EC-2.3.1.21
    docosanoyltransferase, dcsacrn
    myocyte
    CRNDSTp_mc carnitine coa[w] + dcsacrn[y] <==> crn[y] + Fatty Acid Degradation
    docosanoyltransferase II, dcsacoa[w]
    myocyte
    CRNDT_mc carnitine [y]: crn + ddcoa <==> coa + ddcrn Fatty Acid Degradation EC-2.3.1.21
    dodecanoyltransferase,
    myocyte
    CRNDTm_mc carnitine coa[z] + ddcrn[y] <==> crn[y] + Fatty Acid Degradation
    dodecanoyltransferase II, ddcoa[z]
    myocyte
    CRNET_mc carnitine [y]: crn + ecsacoa <==> coa + Fatty Acid Degradation EC-2.3.1.21
    eicosanoyltransferase, ecsacrn
    myocyte
    CRNETm_mc carnitine coa[z] + ecsacrn[y] <==> crn[y] + Fatty Acid Degradation
    eicosanoyltransferase II, ecsacoa[z]
    myocyte
    CRNETp_mc carnitine coa[w] + ecsacrn[y] <==> crn[y] + Fatty Acid Degradation
    eicosanoyltransferase II, ecsacoa[w]
    myocyte
    CRNODET_mc carnitine 9-cis- [y]: crn + odecoa9 <==> coa + Fatty Acid Degradation EC-2.3.1.21
    octadecenoyltransferase, odecrn9
    myocyte
    CRNOT_mc carnitine [y]: crn + strcoa <==> coa + strcrn Fatty Acid Degradation EC-2.3.1.21
    octadecanoyltransferase,
    myocyte
    CRNOTm_mc carnitine coa[z] + strcrn[y] <==> crn[y] + Fatty Acid Degradation
    octadecanoyltransferase strcoa[z]
    II, myocyte
    CRNPTDT_mc carnitine [y]: crn + pdcoa <==> coa + pdcrn Fatty Acid Degradation EC-2.3.1.21
    pentadecanoyltransferase,
    myocyte
    CRNPT_mc carnitine O- [y]: crn + pmtcoa --> coa + pmtcrn Fatty Acid Degradation EC-2.3.1.21
    palmitoyltransferase,
    myocyte
    CRNPTm_mc carnitine O- coa[z] + pmtcrn[y] --> crn[y] + Fatty Acid Degradation
    palmitoyltransferase II, pmtcoa[z]
    myocyte
    CRNTT_mc carnitine [y]: crn + tdcoa <==> coa + tdcrn Fatty Acid Degradation EC-2.3.1.21
    tetradecanoyltransferase,
    myocyte
    CRNTTm_mc carnitine coa[z] + tdcrn[y] <==> crn[y] + Fatty Acid Degradation
    tetradecanoyltransferase tdcoa[z]
    II, myocyte
    DDCIm_mc dodecenoyl-CoA D- [z]: cis-dd2coa <==> trans-dd2coa Fatty Acid Degradation EC-5.3.3.8
    isomerase, myocyte
    mitochondrial
    ECOAH10m_mc 3-hydroxyacyl-CoA [z]: 3hdcoa <==> dc2coa + h2o Fatty Acid Degradation EC-4.2.1.17
    dehydratase (3-
    hydroxydecanoyl-CoA)
    ECOAH11m_mc 3-hydroxyacyl-CoA [z]: 3hedcoa <==> ed2coa + h2o Fatty Acid Degradation EC-4.2.1.17
    dehydratase (3-
    hydroxyendecanoyl-CoA)
    ECOAH12m_mc 3-hydroxyacyl-CoA [z]: 3hddcoa <==> h2o + trans- Fatty Acid Degradation EC-4.2.1.17
    dehydratase (3- dd2coa
    hydroxydodecanoyl-CoA)
    ECOAH13m_mc 3-hydroxyacyl-CoA [z]: 3htrdcoa <==> h2o + trd2coa Fatty Acid Degradation EC-4.2.1.17
    dehydratase (3-
    hydroxytridecanoyl-CoA)
    ECOAH145m_mc 3-hydroxyacyl-CoA [z]: 3htdecoa5 <==> h2o + Fatty Acid Degradation EC-4.2.1.17
    dehydratase (3- tde2coa5
    hydroxytetradecenoyl-
    CoA, C14:1CoA, n-5)
    ECOAH14m_mc 3-hydroxyacyl-CoA [z]: 3htdcoa <==> h2o + td2coa Fatty Acid Degradation EC-4.2.1.17
    dehydratase (3-
    hydroxytetradecanoyl-
    CoA)
    ECOAH15m_mc 3-hydroxyacyl-CoA [z]: 3hpdcoa <==> h2o + pd2coa Fatty Acid Degradation EC-4.2.1.17
    dehydratase (3-
    hydroxypentadecanoyl-
    CoA)
    ECOAH167m_mc 3-hydroxyacyl-CoA [z]: 3hhdecoa7 <==> h2o + Fatty Acid Degradation EC-4.2.1.17
    dehydratase (3- hde2coa7
    hydroxyhexadecenoyl-
    CoA, C16:1CoA, n-7)
    ECOAH16m_mc 3-hydroxyacyl-CoA [z]: 3hhdcoa <==> h2o + hdd2coa Fatty Acid Degradation EC-4.2.1.17
    dehydratase (3-
    hydroxyhexadecanoyl-
    CoA)
    ECOAH189m_mc 3-hydroxyacyl-CoA [z]: 3hodecoa9 <==> h2o + Fatty Acid Degradation EC-4.2.1.17
    dehydratase (3- ode2coa9
    hydroxyoctadecenoyl-CoA,
    C18:1CoA, n-9)
    ECOAH18m_mc 3-hydroxyacyl-CoA [z]: 3hodcoa <==> h2o + od2coa Fatty Acid Degradation EC-4.2.1.17
    dehydratase (3-
    hydroxyoctadecanoyl-CoA,
    C18:0CoA)
    ECOAH20m_mc 3-hydroxyacyl-CoA [z]: 3hescoa <==> es2coa + h2o Fatty Acid Degradation EC-4.2.1.17
    dehydratase (3-
    hydroxyeicosanoyl-CoA,
    C18:0CoA)
    ECOAH22p_mc 3-hydroxyacyl-CoA [w]: 3hdscoa <==> ds2coa + h2o Fatty Acid Degradation EC-4.2.1.17
    dehydratase (3-
    hydroxydocosanoyl-CoA,
    C18:0CoA)
    ECOAH4m_mc 3-hydroxyacyl-CoA [z]: 3hbycoa <==> b2coa + h2o Fatty Acid Degradation EC-4.2.1.17
    dehydratase (3-
    hydroxybutanoyl-CoA)
    ECOAH5m_mc 3-hydroxyacyl-CoA [z]: 3hptcoa <==> h2o + pt2coa Fatty Acid Degradation EC-4.2.1.17
    dehydratase (3-
    hydroxypentanoyl-CoA)
    ECOAH6m_mc 3-hydroxyacyl-CoA [z]: 3hhcoa <==> h2o + hx2coa Fatty Acid Degradation EC-4.2.1.17
    dehydratase (3-
    hydroxyhexanoyl-CoA)
    ECOAH7m_mc 3-hydroxyacyl-CoA [z]: 3hhpcoa <==> h2o + hp2coa Fatty Acid Degradation EC-4.2.1.17
    dehydratase (3-
    hydroxyheptanoyl-CoA)
    ECOAH8m_mc 3-hydroxyacyl-CoA [z]: 3hocoa <==> h2o + oc2coa Fatty Acid Degradation EC-4.2.1.17
    dehydratase (3-
    hydroxyoctanoyl-CoA)
    ECOAH9m_mc 3-hydroxyacyl-CoA [z]: 3hnncoa <==> h2o + nn2coa Fatty Acid Degradation EC-4.2.1.17
    dehydratase (3-
    hydroxynonanoyl-CoA)
    HACD10m_mc 3-hydroxyacyl-CoA [z]: 3odcoa + h + nadh <==> Fatty Acid Degradation EC-1.1.1.35
    dehydrogenase (3- 3hdcoa + nad
    oxodecanoyl-CoA)
    HACD11m_mc 3-hydroxyacyl-CoA [z]: 3oedcoa + h + nadh <==> Fatty Acid Degradation EC-1.1.1.35
    dehydrogenase (3- 3hedcoa + nad
    oxoendecanoyl-CoA)
    HACD12m_mc 3-hydroxyacyl-CoA [z]: 3oddcoa + h + nadh <==> Fatty Acid Degradation EC-1.1.1.35
    dehydrogenase (3- 3hddcoa + nad
    oxododecanoyl-CoA)
    HACD13m_mc 3-hydroxyacyl-CoA [z]: 3otrdcoa + h + nadh <==> Fatty Acid Degradation EC-1.1.1.35
    dehydrogenase (3- 3htrdcoa + nad
    oxotridecanoyl-CoA)
    HACD145m_mc 3-hydroxyacyl-CoA [z]: 3otdecoa5 + h + nadh <==> Fatty Acid Degradation EC-1.1.1.35
    dehydrogenase (3- 3htdecoa5 + nad
    oxotetradecenoyl-CoA
    C14:1CoA, n-5)
    HACD14m_mc 3-hydroxyacyl-CoA [z]: 3otdcoa + h + nadh <==> Fatty Acid Degradation EC-1.1.1.35
    dehydrogenase (3- 3htdcoa + nad
    oxotetradecanoyl-CoA)
    HACD15m_mc 3-hydroxyacyl-CoA [z]: 3opdcoa + h + nadh <==> Fatty Acid Degradation EC-1.1.1.35
    dehydrogenase (3- 3hpdcoa + nad
    oxopentadecanoyl-CoA)
    HACD167m_mc 3-hydroxyacyl-CoA [z]: 3ohdecoa7 + h + nadh <==> Fatty Acid Degradation EC-1.1.1.35
    dehydrogenase (3- 3hhdecoa7 + nad
    oxohexadecenoyl-CoA
    C16:1CoA, n-7)
    HACD16m_mc 3-hydroxyacyl-CoA [z]: 3ohdcoa + h + nadh <==> Fatty Acid Degradation EC-1.1.1.35
    dehydrogenase (3- 3hhdcoa + nad
    oxohexadecanoyl-CoA)
    HACD189m_mc 3-hydroxyacyl-CoA [z]: 3oodcecoa9 + h + nadh <==> Fatty Acid Degradation EC-1.1.1.35
    dehydrogenase (3- 3hodecoa9 + nad
    oxooctadecenoyl-CoA
    C18:1CoA, n-9)
    HACD18m_mc 3-hydroxyacyl-CoA [z]: 3oodcoa + h + nadh <==> Fatty Acid Degradation EC-1.1.1.35
    dehydrogenase (3- 3hodcoa + nad
    oxooctadecanoyl-CoA
    C18:0CoA)
    HACD20m_mc 3-hydroxyacyl-CoA [z]: 3oescoa + h + nadh <==> Fatty Acid Degradation EC-1.1.1.35
    dehydrogenase (3- 3hescoa + nad
    oxoeicosanoyl-CoA
    C18:0CoA)
    HACD22p_mc 3-hydroxyacyl-CoA [z]: 3odscoa + h + nadh <==> Fatty Acid Degradation EC-1.1.1.35
    dehydrogenase (3- 3hdscoa + nad
    oxodocosanoyl-CoA
    C18:0CoA)
    HACD4m_mc 3-hydroxyacyl-CoA [z]: aacoa + h + nadh <==> Fatty Acid Degradation EC-1.1.1.35
    dehydrogenase (3- 3hbycoa + nad
    oxobutanoyl-CoA)
    HACD5m_mc 3-hydroxyacyl-CoA [z]: 3optcoa + h + nadh <==> Fatty Acid Degradation EC-1.1.1.35
    dehydrogenase (3- 3hptcoa + nad
    oxopentanoyl-CoA)
    HACD6m_mc 3-hydroxyacyl-CoA [z]: 3ohcoa + h + nadh <==> Fatty Acid Degradation EC-1.1.1.35
    dehydrogenase (3- 3hhcoa + nad
    oxohexanoyl-CoA)
    HACD7m_mc 3-hydroxyacyl-CoA [z]: 3ohpcoa + h + nadh <==> Fatty Acid Degradation EC-1.1.1.35
    dehydrogenase (3- 3hhpcoa + nad
    oxoheptanoyl-CoA)
    HACD8m_mc 3-hydroxyacyl-CoA [z]: 3oocoa + h + nadh <==> Fatty Acid Degradation EC-1.1.1.35
    dehydrogenase (3- 3hocoa + nad
    oxooctanoyl-CoA)
    HACD9m_mc 3-hydroxyacyl-CoA [z]: 3onncoa + h + nadh <==> Fatty Acid Degradation EC-1.1.1.35
    dehydrogenase (3- 3hnncoa + nad
    oxononanoyl-CoA)
    MMEm_mc methylmalonyl-CoA [z]: mmcoa-S <==> mmcoa-R Fatty Acid Degradation EC-5.1.99.1
    epimerase, myocyte
    mitochondrial
    MMMm_mc R-methylmalonyl-CoA [z]: mmcoa-R --> succoa Fatty Acid Degradation EC-5.4.99.2
    mutase, myocyte
    mitochondrial
    PPCOACm_mc Propionyl-CoA [z]: atp + hco3 + ppcoa --> adp + h + Fatty Acid Degradation EC-6.4.1.3
    carboxylase, myocyte mmcoa-S + pi
    mitochondrial
    FACOAL120_mc fatty-acid--CoA ligase [y]: atp + coa + ddca <==> amp + Fatty Acid Metabolism EC-6.2.1.3
    (dodecanoate, C12:0), ddcoa + ppi
    myocyte
    FACOAL140_mc fatty-acid--CoA ligase [y]: atp + coa + ttdca <==> amp + Fatty Acid Metabolism EC-6.2.1.3
    (tetradecanoate, C14:0), ppi + tdcoa
    myocyte
    FACOAL150_mc fatty-acid--CoA ligase [y]: atp + coa + ptdca <==> amp + Fatty Acid Metabolism EC-6.2.1.3
    (pentadecanoate, C15:0), pdcoa + ppi
    myocyte
    FACOAL160_mc fatty-acid--CoA ligase [y]: atp + coa + hdca <==> amp + Fatty Acid Metabolism EC-6.2.1.3
    (hexadecanoate, C16:0), pmtcoa + ppi
    myocyte
    FACOAL180_mc fatty-acid--CoA ligase [y]: atp + coa + ocdca <==> amp + Fatty Acid Metabolism EC-6.2.1.3
    (octadecanoate, C28:0), ppi + strcoa
    myocyte
    FACOAL181_9_mc fatty-acid--CoA ligase [y]: atp + coa + ocdcea9 <==> Fatty Acid Metabolism EC-6.2.1.3
    (octadecenoate, C18:1 n- amp + odecoa9 + ppi
    9), myocyte
    FACOAL200_mc fatty-acid--CoA ligase [y]: atp + coa + ecsa <==> amp + Fatty Acid Metabolism EC-6.2.1.3
    (eicosanoate, C20:0), ecsacoa + ppi
    myocyte
    ACCOAC_ac acetyl-CoA carboxylase [a]: accoa + atp + hco3 --> adp + h + Fatty Acid Synthesis EC-6.4.1.2
    malcoa + pi
    AGAT_ac_HS_ub unbalanced 1-Acyl- [a]: 1ag3p_HS + (0.00032) Fatty Acid Synthesis
    glycerol-3-phosphate dcsacoa + (0.00698) ddcoa +
    acyltransferase, adipocyte (0.00024) dsecoa11 + (0.00056)
    cytosol, Homo sapiens dsecoa9 + (0.00172) dshcoa3 +
    specific (0.00163) dspcoa3 + (0.00016)
    dspcoa6 + (0.00182) ecsacoa +
    (0.00272) esdcoa6 + (0.00035)
    esdcoa9 + (0.00148) esecoa11 +
    (0.00026) esecoa7 + (0.00732)
    esecoa9 + (0.00036) espcoa3 +
    (0.00027) estcoa3 + (0.0023)
    estcoa6 + (0.00027) ettcoa3 +
    (0.00311) ettcoa6 + (0.02985)
    hdcoa7 + (0.00582) hdcoa9 +
    (0.00295) hpdcoa8 + (0.15761)
    ocdycacoa6 + (0.00499) odcoa3 +
    (0.00039) odcoa6 + (0.0026)
    odecoa5 + (0.01831) odecoa7 +
    (0.39309) odecoa9 + (0.00138)
    osttcoa6 + (0.00375) pdcoa +
    (0.24351) pmtcoa + (0.06379)
    strcoa + (0.03728) tdcoa +
    (0.00244) tdecoa5 + (0.00037)
    tdecoa7 --> coa + pa_HS
    DESAT141_5_ac Myristicoyl-CoA [a]: h + nadph + o2 + tdcoa --> (2) Fatty Acid Synthesis EC-1.14.19.1
    desaturase (n-C14:0CoA -> h2o + nadp + tdecoa5
    C14:1CoA, n-5),
    adipocyte
    DESAT141_7_ac Myristicoyl-CoA [a]: h + nadph + o2 + tdcoa --> (2) Fatty Acid Synthesis EC-1.14.19.1
    desaturase (n-C14:0CoA -> h2o + nadp + tdecoa7
    C14:1CoA, n-7),
    adipocyte
    DESAT161_7_ac Palmitoyl-CoA desaturase [a]: h + nadph + o2 + pmtcoa --> Fatty Acid Synthesis EC-1.14.19.1
    (n-C16:0CoA -> (2) h2o + hdcoa7 + nadp
    C16:1CoA, n-7), adipocyte
    DESAT161_9_ac Palmitoyl-CoA desaturase [a]: h + nadph + o2 + pmtcoa --> Fatty Acid Synthesis EC-1.14.19.1
    (n-C16:0CoA -> (2) h2o + hdcoa9 + nadp
    C16:1CoA, n-9), adipocyte
    DESAT171_8_ac Palmitoyl-CoA desaturase [a]: h + hpdcoa + nadph + o2 --> Fatty Acid Synthesis EC-1.14.19.1
    (n-C17:0CoA -> (2) h2o + hpdcoa8 + nadp
    C17:1CoA, n-8), adipocyte
    DESAT181_5_ac stearoyl-CoA desaturase [a]: h + nadph + o2 + strcoa --> (2) Fatty Acid Synthesis EC-1.14.19.1
    (n-C18:0CoA -> h2o + nadp + odecoa5
    C18:1CoA, n-5), adipocyte
    DESAT181_7_ac stearoyl-CoA desaturase [a]: h + nadph + o2 + strcoa --> (2) Fatty Acid Synthesis EC-1.14.19.1
    (n-C18:0CoA -> h2o + nadp + odecoa7
    C18:1CoA, n-7), adipocyte
    DESAT181_9_ac stearoyl-CoA desaturase [a]: h + nadph + o2 + strcoa --> (2) Fatty Acid Synthesis EC-1.14.19.1
    (n-C18:0CoA -> h2o + nadp + odecoa9
    C18:1CoA, n-9), adipocyte
    DESAT201_11_ac stearoyl-CoA desaturase [a]: ecsacoa + h + nadph + o2 --> Fatty Acid Synthesis EC-1.14.19.1
    (n-C20:0CoA -> esecoa11 + (2) h2o + nadp
    C20:1CoA, n-11),
    adipocyte
    DESAT201_7_ac stearoyl-CoA desaturase [a]: ecsacoa + h + nadph + o2 --> Fatty Acid Synthesis EC-1.14.19.1
    (n-C20:0CoA -> esecoa7 + (2) h2o + nadp
    C20:1CoA, n-7), adipocyte
    DESAT201_9_ac stearoyl-CoA desaturase [a]: ecsacoa + h + nadph + o2 --> Fatty Acid Synthesis EC-1.14.19.1
    (n-C20:0CoA -> esecoa9 + (2) h2o + nadp
    C20:1CoA, n-9), adipocyte
    DESAT202_9_ac stearoyl-CoA desaturase [a]: ecsacoa + (2) h + (2) nadph + Fatty Acid Synthesis EC-1.14.19.1
    (lumped: n-C20:0CoA -> (2) o2 --> esdcoa9 + (4) h2o + (2)
    C20:2CoA, n-9), adipocyte nadp
    DESAT221_11_ac stearoyl-CoA desaturase [a]: dcsacoa + h + nadph + o2 --> Fatty Acid Synthesis EC-1.14.19.1
    (n-C22:0CoA -> dsecoa11 + (2) h2o + nadp
    C22:1CoA, n-11),
    adipocyte
    DESAT221_9_ac stearoyl-CoA desaturase [a]: dcsacoa + h + nadph + o2 --> Fatty Acid Synthesis EC-1.14.19.1
    (n-C22:0CoA -> dsecoa9 + (2) h2o + nadp
    C22:1CoA, n-9), adipocyte
    FACOAL120_ac fatty-acid--CoA ligase [a]: atp + coa + ddca <==> amp + Fatty Acid Synthesis EC-6.2.1.3
    (dodecanoate, C12:0), ddcoa + ppi
    adipocyte
    FACOAL140_ac fatty-acid--CoA ligase [a]: atp + coa + ttdca <==> amp + Fatty Acid Synthesis EC-6.2.1.3
    (tetradecanoate, C14:0), ppi + tdcoa
    adipocyte
    FACOAL141_5_ac fatty-acid--CoA ligase [a]: atp + coa + ttdcea5 <==> amp + Fatty Acid Synthesis EC-6.2.1.3
    (tetradecenoate, C14:1 n- ppi + tdecoa5
    5), adipocyte
    FACOAL141_7_ac fatty-acid--CoA ligase [a]: atp + coa + ttdcea7 <==> amp + Fatty Acid Synthesis EC-6.2.1.3
    (tetradecenoate, C14:1 n- ppi + tdecoa7
    7), adipocyte
    FACOAL150_ac fatty-acid--CoA ligase [a]: atp + coa + ptdca <==> amp + Fatty Acid Synthesis EC-6.2.1.3
    (heptadecanoate, C15:0), pdcoa + ppi
    adipocyte
    FACOAL160_ac fatty-acid--CoA ligase [a]: atp + coa + hdca <==> amp + Fatty Acid Synthesis EC-6.2.1.3
    (hexadecanoate, C16:0), pmtcoa + ppi
    adipocyte
    FACOAL161_7_ac fatty-acid--CoA ligase [a]: atp + coa + hdcea7 <==> amp + Fatty Acid Synthesis EC-6.2.1.3
    (hexadecenoate, C16:1 n- hdcoa7 + ppi
    7), adipocyte
    FACOAL161_9_ac fatty-acid--CoA ligase [a]: atp + coa + hdcea9 <==> amp + Fatty Acid Synthesis EC-6.2.1.3
    (hexadecenoate, C16:1 n- hdcoa9 + ppi
    9), adipocyte
    FACOAL170_ac fatty-acid--CoA ligase [a]: atp + coa + hpdca <==> amp + Fatty Acid Synthesis EC-6.2.1.3
    (heptadecanoate, C17:0), hpdcoa + ppi
    adipocyte
    FACOAL171_8_ac fatty-acid--CoA ligase [a]: atp + coa + hpdcea8 <==> Fatty Acid Synthesis EC-6.2.1.3
    (heptadecenoate, C17:1 n- amp + hpdcoa8 + ppi
    8), adipocyte
    FACOAL180_ac fatty-acid--CoA ligase [a]: atp + coa + ocdca <==> amp + Fatty Acid Synthesis EC-6.2.1.3
    (octadecanoate, C18:0), ppi + strcoa
    adipocyte
    FACOAL181_5_ac fatty-acid--CoA ligase [a]: atp + coa + ocdcea5 <==> Fatty Acid Synthesis EC-6.2.1.3
    (octadecenoate, C18:1 n- amp + odecoa5 + ppi
    5), adipocyte
    FACOAL181_7_ac fatty-acid--CoA ligase [a]: atp + coa + ocdcea7 <==> Fatty Acid Synthesis EC-6.2.1.3
    (octadecenoate, C18:1 n- amp + odecoa7 + ppi
    7), adipocyte
    FACOAL181_9_ac fatty-acid--CoA ligase [a]: atp + coa + ocdcea9 <==> Fatty Acid Synthesis EC-6.2.1.3
    (octadecenoate, C18:1 n- amp + odecoa9 + ppi
    9), adipocyte
    FACOAL182_6_ac fatty-acid--CoA ligase [a]: atp + coa + ocddea6 <==> Fatty Acid Synthesis EC-6.2.1.3
    (octadecadienoate, C18:2 amp + ocdycacoa6 + ppi
    n-6), adipocyte
    FACOAL183_3_ac fatty-acid--CoA ligase [a]: atp + coa + ocdctra3 <==> Fatty Acid Synthesis EC-6.2.1.3
    (octadecadienoate, C18:3 amp + odcoa3 + ppi
    n-3), adipocyte
    FACOAL183_6_ac fatty-acid--CoA ligase [a]: atp + coa + ocdctra6 <==> Fatty Acid Synthesis EC-6.2.1.3
    (octadecadienoate, C18:3 amp + odcoa6 + ppi
    n-6), adipocyte
    FACOAL200_ac fatty-acid--CoA ligase [a]: atp + coa + ecsa <==> amp + Fatty Acid Synthesis EC-6.2.1.3
    (eicosanoate, C20:0), ecsacoa + ppi
    adipocyte
    FACOAL201_11_ac fatty-acid--CoA ligase [a]: atp + coa + ecsea11 <==> Fatty Acid Synthesis EC-6.2.1.3
    (eicosenoate, C20:1 n-11), amp + esecoa11 + ppi
    adipocyte
    FACOAL201_7_ac fatty-acid--CoA ligase [a]: atp + coa + ecsea7 <==> amp + Fatty Acid Synthesis EC-6.2.1.3
    (eicosenoate, C20:1 n-7), esecoa7 + ppi
    adipocyte
    FACOAL201_9_ac fatty-acid--CoA ligase [a]: atp + coa + ecsea9 <==> amp + Fatty Acid Synthesis EC-6.2.1.3
    (eicosenoate, C20:1 n-9), esecoa9 + ppi
    adipocyte
    FACOAL202_6_ac fatty-acid--CoA ligase [a]: atp + coa + ecsdea6 <==> Fatty Acid Synthesis EC-6.2.1.3
    (eicosadienoate, C20:2 n- amp + esdcoa6 + ppi
    6), adipocyte
    FACOAL202_9_ac fatty-acid--CoA ligase [a]: atp + coa + ecsdea9 <==> Fatty Acid Synthesis EC-6.2.1.3
    (eicosadienoate, C20:2 n- amp + esdcoa9 + ppi
    9), adipocyte
    FACOAL203_3_ac fatty-acid--CoA ligase [a]: atp + coa + ecstea3 <==> amp + Fatty Acid Synthesis EC-6.2.1.3
    (eicosatrienoate, C20:3 n- estcoa3 + ppi
    6), adipocyte
    FACOAL203_6_ac fatty-acid--CoA ligase [a]: atp + coa + ecstea6 <==> amp + Fatty Acid Synthesis EC-6.2.1.3
    (eicosatrienoate, C20:3 n- estcoa6 + ppi
    6), adipocyte
    FACOAL204_3_ac fatty-acid--CoA ligase [a]: atp + coa + ecsttea3 <==> Fatty Acid Synthesis EC-6.2.1.3
    (eicosatetraenoate, C20:4 amp + ettcoa3 + ppi
    n-3), adipocyte
    FACOAL204_6_ac fatty-acid--CoA ligase [a]: atp + coa + ecsttea6 <==> Fatty Acid Synthesis EC-6.2.1.3
    (eicosatetraenoate, C20:4 amp + ettcoa6 + ppi
    n-6), adipocyte
    FACOAL205_3_ac fatty-acid--CoA ligase [a]: atp + coa + ecspea3 <==> Fatty Acid Synthesis EC-6.2.1.3
    (eicosapentaenoate, amp + espcoa3 + ppi
    C20:5 n-3), adipocyte
    FACOAL220_ac fatty-acid--CoA ligase [a]: atp + coa + dcsa <==> amp + Fatty Acid Synthesis EC-6.2.1.3
    (docosanoate, C22:0), dcsacoa + ppi
    adipocyte
    FACOAL221_11_ac fatty-acid--CoA ligase [a]: atp + coa + dcsea11 <==> Fatty Acid Synthesis EC-6.2.1.3
    (docosenoate, C22:1 n- amp + dsecoa11 + ppi
    11), adipocyte
    FACOAL221_9_ac fatty-acid--CoA ligase [a]: atp + coa + dcsea9 <==> amp + Fatty Acid Synthesis EC-6.2.1.3
    (docosenoate, C22:1 n-9), dsecoa9 + ppi
    adipocyte
    FACOAL224_6_ac fatty-acid--CoA ligase [a]: atp + coa + ocsttea6 <==> Fatty Acid Synthesis EC-6.2.1.3
    (ocosatetraenoate, C22:4 amp + osttcoa6 + ppi
    n-6), adipocyte
    FACOAL225_3_ac fatty-acid--CoA ligase [a]: atp + coa + dcspea3 <==> Fatty Acid Synthesis EC-6.2.1.3
    (docosapentaenoate, amp + dspcoa3 + ppi
    C22:5 n-3), adipocyte
    FACOAL225_6_ac fatty-acid--CoA ligase [a]: atp + coa + dcspea6 <==> Fatty Acid Synthesis EC-6.2.1.3
    (docosapentaenoate, amp + dspcoa6 + ppi
    C22:5 n-6), adipocyte
    FACOAL226_6_ac fatty-acid--CoA ligase [a]: atp + coa + dcshea3 <==> Fatty Acid Synthesis EC-6.2.1.3
    (docosahexaenoate, amp + dshcoa3 + ppi
    C22:6 n-6), adipocyte
    FAS100_ac fatty acid synthase (n- [a]: (3) h + malcoa + (2) nadph + Fatty Acid Synthesis EC-2.3.1.85
    C10:0), adipocyte octa --> co2 + coa + dca + h2o +
    (2) nadp
    FAS120_ac fatty acid synthase (n- [a]: dca + (3) h + malcoa + (2) Fatty Acid Synthesis EC-2.3.1.85
    C12:0), adipocyte nadph --> co2 + coa + ddca + h2o +
    (2) nadp
    FAS140_ac fatty acid synthase (n- [a]: ddca + (3) h + malcoa + (2) Fatty Acid Synthesis EC-2.3.1.85
    C14:0), adipocyte nadph --> co2 + coa + h2o + (2)
    nadp + ttdca
    FAS150_ac fatty acid synthase [a]: (17) h + (6) malcoa + (12) Fatty Acid Synthesis
    (C15:0), adipocyte cytosol nadph + ppcoa --> (6) co2 + (7)
    coa + (5) h2o + (12) nadp + ptdca
    FAS160_ac fatty acid synthase (n- [a]: (3) h + malcoa + (2) nadph + Fatty Acid Synthesis EC-2.3.1.85
    C16:0), adipocyte ttdca --> co2 + coa + h2o + hdca +
    (2) nadp
    FAS170_ac fatty acid synthase [a]: (3) h + malcoa + (2) nadph + Fatty Acid Synthesis
    (C17:0), adipocyte cytosol ptdca --> co2 + coa + h2o + hpdca +
    (2) nadp
    FAS180_ac fatty acid synthase (n- [a]: (3) h + hdca + malcoa + (2) Fatty Acid Synthesis EC-2.3.1.85
    C18:0), adipocyte nadph --> co2 + coa + h2o + (2)
    nadp + ocdca
    FAS200_ac fatty acid synthase (n- [a]: (3) h + malcoa + (2) nadph + Fatty Acid Synthesis EC-2.3.1.85
    C20:0), adipocyte ocdca --> co2 + coa + ecsa + h2o +
    (2) nadp
    FAS220_ac fatty acid synthase (n- [a]: ecsa + (3) h + malcoa + (2) Fatty Acid Synthesis EC-2.3.1.85
    C22:0), adipocyte nadph --> co2 + coa + dcsa + h2o +
    (2) nadp
    FAS80_L_ac fatty acid synthase (n- [a]: accoa + (8) h + (3) malcoa + Fatty Acid Synthesis EC-2.3.1.85
    C8:0), lumped reaction, (6) nadph --> (3) co2 + (4) coa +
    adipocyte (2) h2o + (6) nadp + octa
    GAT1_ac_HS_ub unbalanced glycerol 3- [a]: (0.00032) dcsacoa + Fatty Acid Synthesis
    phosphate acyltransferase (0.00698) ddcoa + (0.00024)
    (glycerol 3-phosphate), dsecoa11 + (0.00056) dsecoa9 +
    adipocyte cytosol, Homo (0.00172) dshcoa3 + (0.00163)
    sapiens specific dspcoa3 + (0.00016) dspcoa6 +
    (0.00182) ecsacoa + (0.00272)
    esdcoa6 + (0.00035) esdcoa9 +
    (0.00148) esecoa11 + (0.00026)
    esecoa7 + (0.00732) esecoa9 +
    (0.00036) espcoa3 + (0.00027)
    estcoa3 + (0.0023) estcoa6 +
    (0.00027) ettcoa3 + (0.00311)
    ettcoa6 + glyc3p + (0.02985)
    hdcoa7 + (0.00582) hdcoa9 +
    (0.00295) hpdcoa8 + (0.15761)
    ocdycacoa6 + (0.00499) odcoa3 +
    (0.00039) odcoa6 + (0.0026)
    odecoa5 + (0.01831) odecoa7 +
    (0.39309) odecoa9 + (0.00138)
    osttcoa6 + (0.00375) pdcoa +
    (0.24351) pmtcoa + (0.06379)
    strcoa + (0.03728) tdcoa +
    (0.00244) tdecoa5 + (0.00037)
    tdecoa7 --> 1ag3p_HS + coa
    12DGRH_ac_HS_ub unbalanced diacylglycerol [a]: 12dgr_HS + h2o --> (0.00032) Triglycerol Degradation EC-3.1.1.3
    hydrolase, adipocyte dcsa + (0.00024) dcsea11 +
    cytosol, Homo sapiens (0.00056) dcsea9 + (0.00172)
    specific dcshea3 + (0.00163) dcspea3 +
    (0.00016) dcspea6 + (0.00698)
    ddca + (0.00182) ecsa + (0.00272)
    ecsdea6 + (0.00035) ecsdea9 +
    (0.00148) ecsea11 + (0.00026)
    ecsea7 + (0.00732) ecsea9 +
    (0.00036) ecspea3 + (0.00027)
    ecstea3 + (0.0023) ecstea6 +
    (0.00027) ecsttea3 + (0.00311)
    ecsttea6 + h + (0.24351) hdca +
    (0.02985) hdcea7 + (0.00582)
    hdcea9 + (0.00295) hpdcea8 +
    mglyc_HS + (0.06379) ocdca +
    (0.0026) ocdcea5 + (0.01831)
    ocdcea7 + (0.39309) ocdcea9 +
    (0.00499) ocdctra3 + (0.00039)
    ocdctra6 + (0.15761) ocddea6 +
    (0.00138) ocsttea6 + (0.00375)
    ptdca + (0.03728) ttdca +
    (0.00244) ttdcea5 + (0.00037)
    ttdcea7
    MGLYCH_ac_HS_ub unbalanced monoglycerol [a]: h2o + mglyc_HS --> (0.00032) Triglycerol Degradation EC-3.1.1.3
    hydrolase, adipocyte dcsa + (0.00024) dcsea11 +
    cytosol, Homo sapiens (0.00056) dcsea9 + (0.00172)
    specific dcshea3 + (0.00163) dcspea3 +
    (0.00016) dcspea6 + (0.00698)
    ddca + (0.00182) ecsa + (0.00272)
    ecsdea6 + (0.00035) ecsdea9 +
    (0.00148) ecsea11 + (0.00026)
    ecsea7 + (0.00732) ecsea9 +
    (0.00036) ecspea3 + (0.00027)
    ecstea3 + (0.0023) ecstea6 +
    (0.00027) ecsttea3 + (0.00311)
    ecsttea6 + glyc + h + (0.24351)
    hdca + (0.02985) hdcea7 +
    (0.00582) hdcea9 + (0.00295)
    hpdcea8 + (0.06379) ocdca +
    (0.0026) ocdcea5 + (0.01831)
    ocdcea7 + (0.39309) ocdcea9 +
    (0.00499) ocdctra3 + (0.00039)
    ocdctra6 + (0.15761) ocddea6 +
    (0.00138) ocsttea6 + (0.00375)
    ptdca + (0.03728) ttdca +
    (0.00244) ttdcea5 + (0.00037)
    ttdcea7
    TRIGH_ac_HS_ub unbalanced triacylglycerol [a]: h2o + triglyc_HS --> Triglycerol Degradation EC-3.1.1.3
    hydrolase, adipocyte 12dgr_HS +
    cytosol, Homo sapiens (0.00032) dcsa + (0.00024)
    specific dcsea11 + (0.00056) dcsea9 +
    (0.00172) dcshea3 + (0.00163)
    dcspea3 + (0.00016) dcspea6 +
    (0.00698) ddca + (0.00182) ecsa +
    (0.00272) ecsdea6 + (0.00035)
    ecsdea9 + (0.00148) ecsea11 +
    (0.00026) ecsea7 + (0.00732)
    ecsea9 + (0.00036) ecspea3 +
    (0.00027) ecstea3 + (0.0023)
    ecstea6 + (0.00027) ecsttea3 +
    (0.00311) ecsttea6 + h + (0.24351)
    hdca + (0.02985) hdcea7 +
    (0.00582) hdcea9 + (0.00295)
    hpdcea8 + (0.06379) ocdca +
    (0.0026) ocdcea5 + (0.01831)
    ocdcea7 + (0.39309) ocdcea9 +
    (0.00499) ocdctra3 + (0.00039)
    ocdctra6 + (0.15761) ocddea6 +
    (0.00138) ocsttea6 + (0.00375)
    ptdca + (0.03728) ttdca +
    (0.00244) ttdcea5 + (0.00037)
    ttdcea7
    DAGPYP_ac_HS_ub unbalanced diacylglycerol [a]: h2o + pa_HS --> 12dgr_HS + Triglycerol Synthesis EC-3.1.3.4
    pyrophosphate pi
    phosphatase, adipocyte
    cytosol, Homo sapiens
    specific
    TRIGS_ac_HS_ub unbalanced triglycerol [a]: 12dgr_HS + (0.00032) Triglycerol Synthesis
    synthesis, adipocyte dcsacoa + (0.00698) ddcoa +
    cytosol, Homo sapiens (0.00024) dsecoa11 + (0.00056)
    specific dsecoa9 + (0.00172) dshcoa3 +
    (0.00163) dspcoa3 + (0.00016)
    dspcoa6 + (0.00182) ecsacoa +
    (0.00272) esdcoa6 + (0.00035)
    esdcoa9 + (0.00148) esecoa11 +
    (0.00026) esecoa7 + (0.00732)
    esecoa9 + (0.00036) espcoa3 +
    (0.00027) estcoa3 + (0.0023)
    estcoa6 + (0.00027) ettcoa3 +
    (0.00311) ettcoa6 + (0.02985)
    hdcoa7 + (0.00582) hdcoa9 +
    (0.00295) hpdcoa8 + (0.15761)
    ocdycacoa6 + (0.00499) odcoa3 +
    (0.00039) odcoa6 + (0.0026)
    odecoa5 + (0.01831) odecoa7 +
    (0.39309) odecoa9 + (0.00138)
    osttcoa6 + (0.00375) pdcoa +
    (0.24351) pmtcoa + (0.06379)
    strcoa + (0.03728) tdcoa +
    (0.00244) tdecoa5 + (0.00037)
    tdecoa7 --> coa + triglyc_HS
    NDPK1_ac nucleoside-diphosphate [a]: atp + gdp <==> adp + gtp Nucleotide Metabolism EC-2.7.4.6
    kinase (ATP:GDP)
    NDPK1_mc nucleoside-diphosphate [y]: atp + gdp <==> adp + gtp Nucleotide Metabolism EC-2.7.4.6
    kinase (ATP:GDP)
    ADK1_mc adenylate kinase, myocyte [y]: amp + atp <==> (2) adp Nucleotide Salvage EC-2.7.4.3
    cytosolic Pathways
    NTPP6m_ac Nucleoside triphosphate [b]: atp + h2o --> amp + h + ppi Nucleotide Salvage
    pyrophosphorylase (atp), Pathways
    adipocyte mitochondrial
    ADK1_ac adenylate kinase, [a]: amp + atp <==> (2) adp Nucleotide Savage EC-2.7.4.3
    adipocyte cytosolic Pathway
    CAT_ac catalase, adipocyte [a]: (2) h2o2 --> (2) h2o + o2 Other EC-1.11.1.6
    cytosolic
    HCO3E_ac carbonate dehydratase [a]: co2 + h2o <==> h + hco3 Other EC-4.2.1.1
    (HCO3 equilibration
    reaction), adipocyte
    cytosolic
    HCO3E_mc carbonate dehydratase [y]: co2 + h2o <==> h + hco3 Other EC-4.2.1.1
    (HCO3 equilibration
    reaction), myocyte
    cytosolic
    HCO3Ei carbonate dehydratase [i]: co2 + h2o <==> h + hco3 Other EC-4.2.1.1
    (HCO3 equilibration
    reaction), intra-organism
    NH4DIS_ac nh4 Dissociation [a]: nh4 <==> h + nh3 Other
    CONTRACTION_mc muscle contraction, [y]: myoactinADPPi --> adp + Contraction
    myocyte cytosol myoactin + pi
    MYOADPPIA_mc myosin-ADP-Pi [y]: actin + myosinADPPi --> Contraction
    attachment, myocyte myoactinADPPi
    cytosol
    MYOSINATPB_mc mysosin ATP binding, [y]: atp + myoactin --> actin + Contraction
    myocyte cytosol myosinATP
    MYOSINATPH_mc myosin-ATP hydrolysis, [y]: h2o + myosinATP --> h + Contraction
    myocyte cytosol myosinADPPi
    CREATt2is_mc Creatine Na+ symporter, creat[i] + na1[c] <==> creat[y] + Transport
    myocyte cytosol na1[y]
    CRTNtis_mc creatinine transport, crtn[i] <==> crtn[y] Transport
    myocyte cytosol
    Clt_xo chlorideion transport out cl[e] --> cl[i] Transport
    via diffusion
    DCSAtis_ac docosanoate (C22:0) dcsa[a] --> dcsa[i] Transport
    adipocyte transport
    DCSEA11tis_ac docosenoate (C22:1, n-11) dcsea11[a] --> dcsea11[i] Transport
    adipocyte transport
    DCSEA9tis_ac docosenoate (C22:1, n-9) dcsea9[a] --> dcsea9[i] Transport
    adipocyte transport
    DCSHEA3t docosahexaenoate dcshea3[e] <==> dcshea3[i] Transport
    (C22:6, n-3) transport
    DCSHEA3tis_ac docosahexaenoate dcshea3[i] <==> dcshea3[a] Transport
    (C22:6, n-3) adipocyte
    transport
    DCSPEA3t Docosapentaenoate dcspea3[e] <==> dcspea3[i] Transport
    (C22:5, n-3) transport
    DCSPEA3tis_ac Docosapentaenoate dcspea3[i] <==> dcspea3[a] Transport
    (C22:5, n-3) adipocyte
    transport
    DCSPEA6t Docosapentaenoate dcspea6[e] <==> dcspea6[i] Transport
    (C22:5, n-6) transport
    DCSPEA6tis_ac Docosapentaenoate dcspea6[i] <==> dcspea6[a] Transport
    (C22:5, n-6) adipocyte
    transport
    DDCAtis_ac dodecanoate (C12:0) ddca[a] --> ddca[i] Transport
    adipocyte transport
    DDCAtis_mc dodecanoate (C12:0) ddca[i] --> ddca[y] Transport
    myocyte transport
    ECSAtis_ac eicosanoate (C20:0) ecsa[a] --> ecsa[i] Transport
    adipocyte transport
    ECSDEA6t Eicosadienoate (C20:2, n- ecsdea6[e] <==> ecsdea6[i] Transport
    6) transport
    ECSDEA6tis_ac Eicosadienoate (C20:2, n- ecsdea6[i] <==> ecsdea6[a] Transport
    6) adipocyte transport
    ECSDEA9tis_ac eicosadienoate (C20:2, n- ecsdea9[a] --> ecsdea9[i] Transport
    9) adipocyte transport
    ECSEA11tis_ac eicosenoate (C20:1, n-11) ecsea11[a] --> ecsea11[i] Transport
    adipocyte transport
    ECSEA7tis_ac eicosenoate (C20:1, n-7) ecsea7[a] --> ecsea7[i] Transport
    adipocyte transport
    ECSEA9tis_ac eicosenoate (C20:1, n-9) ecsea9[a] --> ecsea9[i] Transport
    adipocyte transport
    ECSFAtis_mc eicosanoate transport (n- ecsa[i] <==> ecsa[y] Transport
    C20:0)
    ECSPEA3t Eicosapentaenoate ecspea3[e] <==> ecspea3[i] Transport
    (C20:5, n-3) transport
    ECSPEA3tis_ac Eicosapentaenoate ecspea3[i] <==> ecspea3[a] Transport
    (C20:5, n-3) adipocyte
    transport
    ECSTEA3t Eicosatrienoate (C20:3, n- ecstea3[e] <==> ecstea3[i] Transport
    3) transport
    ECSTEA3tis_ac Eicosatrienoate (C20:3, n- ecstea3[i] <==> ecstea3[a] Transport
    3) adipocyte transport
    ECSTEA6t Eicosatrienoate (C20:3, n- ecstea6[e] <==> ecstea6[i] Transport
    6) transport
    ECSTEA6tis_ac Eicosatrienoate (C20:3, n- ecstea6[i] <==> ecstea6[a] Transport
    6) adipocyte transport
    ECSTTEA3t Eicosatetraenoate (C20:4, ecsttea3[e] <==> ecsttea3[i] Transport
    n-3) transport
    ECSTTEA3tis_ac Eicosatetraenoate (C20:4, ecsttea3[i] <==> ecsttea3[a] Transport
    n-3) adipocyte transport
    ECSTTEA6t Eicosatetraenoate (C20:4, ecsttea6[e] <==> ecsttea6[i] Transport
    n-6) transport
    ECSTTEA6tis_ac Eicosatetraenoate (C20:4, ecsttea6[i] <==> ecsttea6[a] Transport
    n-6) adipocyte transport
    GLYCt6is_ac glycerol transport in/out glyc[a] + h[a] <==> glyc[i] + h[i] Transport
    via symporter, adipocyte
    HCO3t2 HCO3 transport out via hco3[e] <==> hco3[i] Transport
    diffusion
    HDCAtis_ac hexadecanoate (C16:0) hdca[a] --> hdca[i] Transport
    adipocyte transport
    HDCAtis_mc hexadecanoate (C16:0) hdca[i] --> hdca[y] Transport
    myocyte transport
    HDCEA7tis_ac hexadecenoate (C16:1, n- hdcea7[a] --> hdcea7[i] Transport
    7) adipocyte transport
    HDCEA9tis_ac hexadecenoate (C16:1, n- hdcea9[a] --> hdcea9[i] Transport
    9) adipocyte transport
    HPDCEA8tis_ac heptadecenoate (C17:1, n- hpdcea8[a] --> hpdcea8[i] Transport
    8) adipocyte transport
    ILEtis_ac L-isoeucine transport h[i] + ile-L[i] <==> h[a] + ile-L[a] Transport TC-2.A.26
    in/out via proton symport,
    adipocyte
    NAt sodium transport in/out via h[i] + na1[e] <==> h[e] + na1[i] Transport TC-2.A.36
    proton antiport (one H+)
    NAtis_mc sodium transport in/out via na1[i] <==> na1[y] Transport TC-1.A.15
    the non-selective cation
    channel
    NH4CLt_xo ammonium chloride cl[i] + nh4[i] <==> cl[e] + nh4[e] Transport
    transport
    NH4tis_ac ammonia transport via nh4[i] <==> nh4[a] Transport
    diffusion, adipocyte
    cytosolic
    OCDCAtis_ac octadecanoate (C18:0) ocdca[a] --> ocdca[i] Transport
    adipocyte transport
    OCDCAtis_mc octadecanoate (C18:0) ocdca[i] --> ocdca[y] Transport
    myocyte transport
    OCDCEA5tis_ac octadecenoate (C18:1, n- ocdcea5[a] --> ocdcea5[i] Transport
    5) adipocyte transport
    OCDCEA7tis_ac octadecenoate (C18:1, n- ocdcea7[a] --> ocdcea7[i] Transport
    7) adipocyte transport
    OCDCEA9tis_ac octadecenoate (C18:1, n- ocdcea9[a] --> ocdcea9[i] Transport
    9) adipocyte transport
    OCDCEA9tis_mc octadecenoate (C18:1, n- ocdcea9[i] --> ocdcea9[y] Transport
    9) myocyte transport
    OCDCTRA3t Octadecatrienoate (C18:3, ocdctra3[e] <==> ocdctra3[i] Transport
    n-3) transport
    OCDCTRA3tis_ac Octadecatrienoate (C18:3, ocdctra3[i] <==> ocdctra3[a] Transport
    n-3) adipocyte transport
    OCDCTRA6t Octadecatrienoate (C18:3, ocdctra6[e] <==> ocdctra6[i] Transport
    n-6) transport
    OCDCTRA6tis_ac Octadecatrienoate (C18:3, ocdctra6[i] <==> ocdctra6[a] Transport
    n-6) adipocyte transport
    OCDDEA6t Octadecadienoate (C18:2, ocddea6[e] <==> ocddea6[i] Transport
    n-6) transport
    OCDDEA6tis_ac Octadecadienoate (C18:2, ocddea6[i] <==> ocddea6[a] Transport
    n-6) adipocyte transport
    OCSTTEA6t Ocosatetraenoate (C22:4, ocsttea6[e] <==> ocsttea6[i] Transport
    n-6) transport
    OCSTTEA6tis_ac Ocosatetraenoate (C22:4, ocsttea6[i] <==> ocsttea6[a] Transport
    n-6) adipocyte transport
    PIt2_xo phosphate transport in via h[e] + pi[e] <==> h[i] + pi[i] Transport
    proton symport
    PTDCAtis_ac pentadecanoate (C15:0) ptdca[a] --> ptdca[i] Transport
    adipocyte transport
    PTDCAtis_mc pentadecanoate (C15:0) ptdca[i] --> ptdca[y] Transport
    myocyte transport
    TTDCAtis_ac tetradecanoate (C14:0) ttdca[a] --> ttdca[i] Transport
    adipocyte transport
    TTDCAtis_mc tetradecanoate (C14:0) ttdca[i] --> ttdcat[y] Transport
    myocyte transport
    TTDCEA5tis_ac tetradecenoate (C14:1, n- ttdcea5[a] --> ttdcea5[i] Transport
    5) adipocyte transport
    TTDCEA7tis_ac tetradecenoate (C14:1, n- ttdcea7[a] --> ttdcea7[i] Transport
    7) adipocyte transport
    G6Pter_ac glucose 6-phosphate g6p[a] <==> g6p[f] Transport,
    adipocyte endoplasmic Endoplasmic Reticular
    reticular transport via
    diffusion
    G6Pter_mc glucose 6-phosphate g6p[y] <==> g6p[u] Transport,
    myocyte endoplasmic Endoplasmic Reticular
    reticular transport via
    diffusion
    GLCter_ac glucose transport, glc-D[a] <==> glc-D[f] Transport,
    endoplasmic reticulum Endoplasmic Reticular
    GLCter_mc glucose transport, glc-D[y] <==> glc-D[u] Transport,
    endoplasmic reticulum Endoplasmic Reticular
    CO2t_xo CO2 transport via diffusion co2[e] <==> co2[i] Transport, Extracellular
    CO2tis_ac CO2 adipocyte transport co2[i] <==> co2[a] Transport, Extracellular
    out via diffusion
    CO2tis_mc CO2 myocyte transport co2[i] <==> co2[y] Transport, Extracellular
    out via diffusion
    CRTNt creatinine transport crtn[i] <==> crtn[e] Transport, Extracellular
    GLCt1_xo glucose transport (uniport: glc-D[e] <==> glc-D[i] Transport, Extracellular
    facilitated diffusion), intra-
    organism
    GLCt1is_ac glucose transport into glc-D[i] <==> glc-D[a] Transport, Extracellular
    adipocyte (uniport:
    facilitated diffusion)
    GLCt1is_mc glucose transport into glc-D[i] <==> glc-D[y] Transport, Extracellular
    myocyte (uniport:
    facilitated diffusion)
    H2Ot5_xo H2O transport via diffusion h2o[e] <==> h2o[i] Transport, Extracellular
    H2Ot5is_ac H2O transport into h2o[i] <==> h2o[a] Transport, Extracellular
    adipocyte via diffusion
    H2Ot5is_mc H2O transport into h2o[i] <==> h2o[y] Transport, Extracellular
    myocyte via diffusion
    ILEt L-isoeucine transport h[e] + ile-L[e] <==> h[i] + ile-L[i] Transport, Extracellular TC-2.A.26
    in/out via proton symport
    L-LACt2_xo L-lactate transport via h[e] + lac-L[e] <==> h[i] + lac-L[i] Transport, Extracellular
    proton symport
    L-LACt2is_mc L-lactate reversible h[i] + lac-L[i] <==> h[y] + lac-L[y] Transport, Extracellular
    transport into myocyte via
    proton symport
    O2t_xo O2 transport via diffusion o2[e] <==> o2[i] Transport, Extracellular
    O2tis_ac O2 transport into o2[i] <==> o2[a] Transport, Extracellular
    adipocyte via diffusion
    O2tis_mc O2 transport into myocyte o2[i] <==> o2[y] Transport, Extracellular
    via diffusion
    Plt2_xo [deleted phosphate transport in via h[e] + pi[e] --> h[i] + pi[i] Transport, Extracellular
    Aug. 26, 2004 proton symport
    01:34:57 PM]
    Plt6is_ac phosphate transport in/out h[i] + pi[i] <==> h[a] + pi[a] Transport, Extracellular TC-2.A.20
    of adipocyte via proton
    symporter
    PIt6is_mc phosphate transport in/out h[i] + pi[i] <==> h[y] + pi[y] Transport, Extracellular TC-2.A.20
    of myocyte via proton
    symporter
    3MOPtm_ac 3-Methyl-2-oxopentanoate 3mop[a] <==> 3mop[b] Transport,
    transport, diffusion, Mitochondrial
    adipocyte mitochondrial
    ATP/ADPtm_ac ATP/ADP transport, adp[a] + atp[b] <==> adp[b] + Transport,
    adipocyte mitochondrial atp[a] Mitochondrial
    ATP/ADPtm_mc ATP/ADP transport, adp[y] + atp[z] <==> adp[z] + atp[y] Transport,
    myocyte mitochondrial Mitochondrial
    CITtam_ac citrate transport, adipocyte cit[a] + mal-L[b] <==> cit[b] + mal- Transport,
    mitochondrial L[a] Mitochondrial
    CITtam_mc citrate transport, myocyte cit[y] + mal-L[z] <==> cit[z] + mal- Transport,
    mitochondrial L[y] Mitochondrial
    CO2tm_ac CO2 transport (diffusion), co2[a] <==> co2[b] Transport,
    adipocyte mitochondrial Mitochondrial
    CO2tm_mc CO2 transport (diffusion), co2[y] <==> co2[z] Transport,
    myocyte mitochondrial Mitochondrial
    CRNCARtm_mc carnithine-acetylcarnithine acrn[y] + crn[z] --> acrn[z] + crn[y] Transport,
    carrier, myocyte Mitochondrial
    mitochondrial
    CRNODETm_mc carnitine 9-cis- coa[z] + odecrn9[y] <==> crn[y] + Transport,
    octadecenoyltransferase odecoa9[z] Mitochondrial
    II, myocyte
    CRNPTDTm_mc carnitine coa[z] + pdcrn[y] <==> crn[y] + Transport,
    pentadecanoyltransferase pdcoa[z] Mitochondrial
    II, myocyte
    DHAP1tm_ac dihydroxyacetone dhap[a] <==> dhap[b] Transport,
    phosphate transport, Mitochondrial
    adipocyte mitochondrial
    DHAP1tm_mc dihydroxyacetone dhap[y] <==> dhap[z] Transport,
    phosphate transport, Mitochondrial
    myocyte mitochondrial
    GACm_ac glutamate aspartate asp-L[b] + glu-L[a] + h[a] --> asp- Transport,
    carrier, adipocyte L[a] + glu-L[b] + h[b] Mitochondrial
    cytosolic/mitochondrial
    GACm_mc glutamate aspartate asp-L[z] + glu-L[y] + h[y] --> asp- Transport,
    carrier, myocyte L[y] + glu-L[z] + h[z] Mitochondrial
    cytosolic/mitochondrial
    GL3Ptm_mc glycerol-3-phosphate glyc3p[y] <==> glyc3p[z] Transport,
    transport, myocyte Mitochondrial
    mitochondrial
    GTPt3m_ac GTP/GDP transporter, gdp[b] + gtp[a] + h[a] --> gdp[a] + Transport,
    adipocyte mitochondrial gtp[b] + h[b] Mitochondrial
    GTPt3m_mc GTP/GDP transporter, gdp[z] + gtp[y] + h[y] --> gdp[y] + Transport,
    myocyte mitochondrial gtp[z] + h[z] Mitochondrial
    H2Otm_ac H2O transport, adipocyte h2o[a] <==> h2o[b] Transport,
    mitochondrial Mitochondrial
    H2Otm_mc H2O transport, myocyte h2o[y] <==> h2o[z] Transport,
    mitochondrial Mitochondrial
    MALAKGtm_ac malate-alphaketoglutarate akg[b] + mal-L[a] --> akg[a] + mal- Transport,
    transporter, adipocyte L[b] Mitochondrial
    mitochondria
    MALAKGtm_mc malate-alphaketoglutarate akg[z] + mal-L[y] --> akg[y] + mal- Transport,
    transporter, myocyte L[z] Mitochondrial
    mitochondria
    O2trm_ac O2 transport into o2[a] <==> o2[b] Transport,
    adipocyte mitochondria Mitochondrial
    (diffusion)
    O2trm_mc O2 transport into myocyte o2[y] <==> o2[z] Transport,
    mitochondria (diffusion) Mitochondrial
    Pltm_ac phosphate transporter, h[a] + pi[a] <==> h[b] + pi[b] Transport,
    adipocyte mitochondrial Mitochondrial
    Pltm_mc phosphate transporter, h[y] + pi[y] <==> h[z] + pi[z] Transport,
    myocyte mitochondrial Mitochondrial
    PPAtm_ac propionate transport in/out h[a] + ppa[a] <==> h[b] + ppa[b] Transport, TC-2.A.20
    via proton symport, Mitochondrial
    adipocyte
    PYRtm_ac pyruvate transport, h[a] + pyr[a] <==> h[b] + pyr[b] Transport,
    adipocyte mitochondrial Mitochondrial
    PYRtm_mc pyruvate transport, h[y] + pyr[y] <==> h[z] + pyr[z] Transport,
    myocyte mitochondrial Mitochondrial
    CRNCARtp_mc carnithine-acetylcarnithine acrn[y] + crn[w] <==> acrn[w] + Transport, Peroxisomal
    carrier, myocyte crn[y]
    peroxixome

Claims (16)

1-60. (canceled)
61. A computer-implemented method for predicting a physiological function of single-celled organisms, comprising:
(a) providing on a computer a first data structure comprising a first stoichiometric matrix having rows and columns of elements that correspond to stoichiometric coefficients of a plurality of first reactions from a first single-celled organism, each of said reactions comprising a reactant identified as a substrate of the reaction and a reactant identified as a product of the reaction, stoichiometric coefficients of the first stoichiometric matrix relating said substrate and said product, wherein at least one reactant in said plurality of reactants or at least one reaction in said plurality of reactions is annotated with an assignment to a subsystem or compartment;
(b) providing on the computer a second data structure comprising a second stoichiometric matrix having rows and columns of elements that correspond to stoichiometric coefficients of a plurality of second reactions from a second single-celled organism, each of said reactions comprising a reactant identified as a substrate of the reaction and a reactant identified as a product of the reaction, stoichiometric coefficients of the second stoichiometric matrix relating said substrate and said product, wherein at least one reactant in said plurality of reactants or at least one reaction in said plurality of reactions is annotated with an assignment to a subsystem or compartment;
(c) providing on the computer a third data structure comprising a third stoichiometric matrix or elements in the first or second stoichiometric matrices having rows and columns of elements that correspond to stoichiometric coefficients of a plurality of intra-system reactions between said first and second single-celled organisms and an intra-cellular system of said first or second single-celled organisms, each of said intra-system reactions comprising a reactant identified as a substrate of the reaction located in one of the first or second single-celled organisms or in the intra-cellular system and a reactant identified as a product of the reaction located in another of the first and second single-celled organisms or in the intra-cellular system, stoichiometric coefficients of the third stoichiometric matrix relating said substrate and said product;
(d) providing on the computer a constraint set for said plurality of reactions for said first, second and third data structures, the constraint set specifying an upper or lower boundary of flux through each of the reactions described in the first, second, and third stoichiometric matrices;
(e) defining on the computer an objective function to be a linear combination of fluxes through the reactions described in the first, second, and third stoichiometric matrices that optimizes cell growth, reproduction, apoptosis, energy production, production of a hormone or extracellular component, a mechanical property, or maintenance of biomass composition and growth rate;
(f) determining on the computer at least one flux distribution for said plurality of first, second and intra-system reactions across said first single-celled organism, said second single-celled organism, and said intra-cellular system by (i) identifying a plurality of flux vectors that each satisfy the stoichiometric matrix and satisfy the constraint set and (ii) identifying at least one linear combination of the flux vectors that minimizes or maximizes the objective function; and
(g) providing output to a user of said at least one flux distribution determined in step (f), wherein said at least one flux distribution is predictive of a physiological function of said first and second single-celled organisms.
62. The method of claim 61, wherein said first data structure comprises a first reaction network.
63. The method of claim 61, wherein said second data structure comprises a second reaction network.
64. The method of claim 61, wherein said first or second data structures comprise a plurality of reaction networks.
65. The method of claim 61, further comprising providing on the computer one or more fourth data structures comprising one or more fourth stoichiometric matrices and one or more fourth constraint sets, each fourth data structure relating a plurality of reactants to a plurality of one or more third reactions from one or more third single-celled organisms, each of said reactions comprising a reactant identified as a substrate of the reaction, a reactant identified as a product of the reaction and a stoichiometric coefficient relating said substrate and said product.
66. The method of claim 65, wherein said one or more fourth data structures comprises a plurality of data structures.
67. The method of claim 66, wherein said plurality of data structures comprise a data structure for a plurality of different single-celled organisms.
68. The method of 65, wherein said one or more third single-celled organism comprises at least 4 single-celled organisms, 5 single-celled organisms, 6 single-celled organisms, 7 single-celled organisms, 8 single-celled organisms, 9 single-celled organisms, 10 single-celled organisms, 100 single-celled organisms, 1000 single-celled organisms, 5000 single-celled organisms, 10,000 single-celled organisms or more.
69. The method of claim 61, wherein said first and second single-celled organisms comprise eukaryotic cells.
70. The method of claim 61, wherein said first and second single-celled organisms comprise prokaryotic cells.
71. The method of claim 61, further comprising accessing with the computer a gene database having information characterizing an associated gene.
72. The method of claim 61, wherein at least one of said reactions is a regulated reaction.
73. The method of claim 72, wherein said constraint set includes a variable constraint for said regulated reaction.
74. The method of claim 61, wherein said intra-system reactions comprise a reactant or reactions selected from the group consisting of a bicarbonate buffer system, an ammonia buffer system, a hormone, a signaling molecule, a vitamin, a mineral or a combination thereof.
75. The method of claim 61, wherein a plurality of reactions is annotated to indicate a plurality of associated genes and wherein said gene database comprises information characterizing said plurality of associated genes.
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