Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
  • G01N30/02—Column chromatography
  • G01N30/86—Signal analysis
  • G01N30/8665—Signal analysis for calibrating the measuring apparatus
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
  • G01N30/02—Column chromatography
  • G01N2030/022—Column chromatography characterised by the kind of separation mechanism
  • G01N2030/027—Liquid chromatography
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
  • G01N30/02—Column chromatography
  • G01N30/04—Preparation or injection of sample to be analysed
  • G01N2030/042—Standards
  • G01N2030/047—Standards external
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
  • G01N30/02—Column chromatography
  • G01N30/88—Integrated analysis systems specially adapted therefor, not covered by a single one of the groups G01N30/04 - G01N30/86
  • G01N2030/8809—Integrated analysis systems specially adapted therefor, not covered by a single one of the groups G01N30/04 - G01N30/86 analysis specially adapted for the sample
  • G01N2030/8813—Integrated analysis systems specially adapted therefor, not covered by a single one of the groups G01N30/04 - G01N30/86 analysis specially adapted for the sample biological materials
  • G01N2030/8831—Integrated analysis systems specially adapted therefor, not covered by a single one of the groups G01N30/04 - G01N30/86 analysis specially adapted for the sample biological materials involving peptides or proteins
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J49/00—Particle spectrometers or separator tubes
  • H01J49/0009—Calibration of the apparatus

Definitions

• the present invention provides reagents for instrumentation quality control and methods of use thereof.
• sets of peptides or other molecules are provided for evaluating the performance of instruments with mass spectrometry (MS) and/or liquid chromatography (LC) functionalities.
• Mass spectrometry provides a rapid and sensitive technique for the determination of the molecular mass of a molecule or mixture of molecules.
• mass spectrometry can provide detailed information regarding, for example, the molecular mass (also referred to as "molecular weight” or "MW") of the original molecule, the molecular masses of peptides generated by proteolytic digestion of the original molecule, the molecular masses of fragments generated during the ionization of the original molecule, and even peptide sequence information for the original molecule and fragments thereof.
• Mass spectrometers are extremely precise; their performance and calibration must be carefully monitored as systematic errors may cause erroneous m/z values or changes in sensitivity.
• the present invention provides reagents comprising two or more distinct-mass versions of each of two or more distinct-structure (e.g., sequence) molecules (e.g., peptide, nucleic acid, peptide nucleic acid, polymer, etc.).
• sequence e.g., sequence
• many embodiments of the present invention are described as comprising or for use with peptide reagents, these embodiments should be viewed more broadly as applying to quality control and performance evaluation reagents comprising other molecules and/or polymers.
• the present invention is not limited to peptide reagents.
• the present invention provides peptide mixtures comprising two or more distinct-mass versions of each of two or more distinct-sequence peptides. In some embodiments, the present invention provides peptide mixtures consisting of, or consisting essentially of, two or more distinct-mass versions of each of two or more distinct- sequence peptides. In some embodiments, each of the distinct-sequence peptides is of distinct hydrophobicity. In some embodiments, all of the distinct-mass versions of any of the distinct-sequence peptides are present at distinct concentrations.
• the distinct-mass versions of any of the distinct-sequence peptides are present at concentrations ranging from at least as low as 0.1 nM to at least as high at 100 ⁇ . In some embodiments, the distinct-mass versions of any of the distinct-sequence peptides are present at
• the distinct-mass versions of any of the distinct-sequence peptides are present in a reagent at zeptomoles to picomoles of total peptide.
• the distinct-sequence peptides are separable by liquid chromatography based on their different hydrophobicities or other chemical properties (e.g., charge, size, or hydrophilicity).
• a peptide mixture comprises 3-20 distinct-sequence peptides.
• a peptide mixture comprises 5-10 distinct-sequence peptides.
• the distinct-mass versions of any of the distinct-sequence peptides are differentiable by mass spectrometry. In some embodiments, the distinct-mass versions of any of the distinct-sequence peptides are the result of different combinations of stable isotope-labeled amino acids. In some embodiments, the distinct-mass versions of any of the distinct-sequence peptides are the result of different combinations of stable isotope of constituent atoms. In some embodiments, each of the distinct-mass versions of any of the distinct-sequence peptides comprises a different number of uniformly stable isotope-labeled amino acids.
• a peptide mixture comprises 3-20 distinct-mass versions of each of the distinct-sequence peptides. In some embodiments, a peptide mixture comprises 5-10 distinct-mass versions of each of the distinct-sequence peptides.
• the present invention provides methods for assessing performance of an instrument with both liquid chromatography (LC) and mass spectrometry (MS) functionalities comprising: (a) introducing a peptide mixture to the instrument, wherein said peptide mixture comprises two or more distinct-mass versions of each of two or more distinct-sequence peptides; (b) analyzing the peptide mixture by LC (consisting of various mobile phases, including but not limited to C 18 , SCX, HILIC etc.); (c) analyzing the peptide mixture by MS (consisting of but not limited to ESI or MALDI methods of ionization); and (d) assessing the performance of the LC and MS functionalities of the instrument based on results of steps (b) and (c).
• LC liquid chromatography
• MS mass spectrometry
• the peptide mixture purified peptides.
• the purified peptides of the peptide mixture are the only peptides introduced to the instrument in step (a).
• the peptide mixture comprises peptides in the presence of one or more impurities.
• the peptide mixture is introduced to the instrument in the presence of one or more other peptides (e.g., background, contaminants, etc.).
• the peptide mixture is a peptide mixture that comprises two or more distinct-mass versions of each of two or more distinct-sequence peptides.
• assessing the performance of the LC and MS functionalities of the instrument comprises reporting one or more LC-parameters for each peptide sequence selected from: retention times, peak height, peak width, peak resolution, and peak symmetry or one or more MS-parameters selected from mass accuracy, mass resolution, sensitivity, dynamic range, linear response, MS/MS spectral quality and sampling and/or isolation efficiency.
• assessing the performance of the LC and MS functionalities of the instrument comprises reporting one or more MS-parameters for each distinctly-massed version of one or more of the peptide sequences selected from:
• the assessment of LC and/or MS performance is provided by a software program.
• the software reports LC and/or MS parameters from a single analysis, the performance history of the instrument or a comparison between multiple LC and/or MS instruments or instrument platforms.
• the software provides a performance score of the LC and/or MS instrument.
• sensitivity and/or performance are evaluated for a neat sample (e.g., reagent without substantial background causing agents).
• sensitivity and/or performance are evaluated for a complex sample (e.g., reagent and background causing agents/peptides).
• the present invention provides methods for assessing performance of an instrument with both liquid chromatography (LC) and mass spectrometry (MS) functionalities comprising: (a) introducing a peptide mixture to the instrument, wherein said peptide mixture comprises two or more distinct-mass versions of each of two or more distinct-sequence peptides, wherein said peptide mixture comprises two or more distinct- mass versions of each of two or more distinct-sequence peptides; (b) analyzing the peptide mixture by LC; (c) analyzing the peptide mixture by MS; and (d) assessing the performance of the LC and MS functionalities of the instrument based on results of steps (b) and (c).
• LC liquid chromatography
• MS mass spectrometry
• distinct-sequence peptides are of distinct hydrophobicities and separable by LC.
• the present invention provides distinct-mass versions that comprise different combinations of heavy isotope labeled amino acids and are resolved by MS.
• the assessment of LC and MS performance is provided by a software program.
• the software reports LC and MS parameters from a single analysis, the performance history of the instrument or a comparison between multiple LC and MS instruments.
• the software provides a performance score of the LC and/or MS instrument.
• the present invention provides reagents and/or methods for quality control and/or evaluating the performance of instruments with mass spectrometry (MS) and/or liquid chromatography (LC) functionalities.
• MS mass spectrometry
• LC liquid chromatography
• both MS and LC functionalities are assessed.
• only one of MS and LC functionalities are assessed.
• an instrument has both MS and LC functionalities, but only one is assessed.
• an instrument has only one of MS and LC functionalities.
• MS and LC functionalities are provided by a single unit.
• MS and LC functionalities are provided by separate units.
• the assessment of the performance of LC and/or MS functionality is performed by software.
• the software generates a performance score.
• a performance score is unique to the tested instrument (or type of instrument tested).
• a performance score can be used for assessment of the tested instrument (or type of instrument tested) at a given time and/or over time.
• a performance score is comparable to performance scores of other similar and/or different instruments (e.g., those with LC and/or MS functionality).
• a performance score can be used for comparison of a tested instrument (or type of instrument tested) to other similar and/or different instruments at a given time and/or over time.
• software is used to track an instruments historical performance.
• a report of instrument performance parameters (e.g., score) is generated .
• the present invention provides methods for assessing performance of an instrument with both liquid chromatography (LC) and mass spectrometry (MS) functionalities comprising: (a) introducing (e.g., injecting) a peptide mixture to the instrument, wherein the peptide mixture comprises two or more distinct-mass versions of each of two or more distinct-sequence peptides; (b) separating or analyzing the peptide mixture by LC; (c) analyzing the peptide mixture by MS; and (d) assessing the performance of the LC and MS functionalities of the instrument based on results of steps (b) and (c) using software.
• LC liquid chromatography
• MS mass spectrometry
• the peptide mixture is a peptide mixture that comprises two or more distinct-mass versions of each of two or more distinct-sequence peptides. In some embodiments, each distinct-mass version of a distinct-sequence peptide is present at a different concentration. In some embodiments, assessing the performance of the LC and MS functionalities of the instrument comprises reporting one or more LC-parameters for each peptide sequence selected from: retention times, peak height, peak width, peak resolution, and peak symmetry.
• assessing the performance of the LC and MS functionalities of the instrument comprises reporting one or more MS -parameters for each distinctly-massed versions of one or more of the peptide sequences selected from: resolution, mass accuracy, sensitivity of "neat” samples, sensitivity within complex samples, dynamic range, mass resolution, isolation efficiency, MS/MS spectral quality and linear response in a single analytical experiment.
• performance is assessed by software which generates a performance score.
• Figure 1 shows an illustration of a chromatogram (top panel) of a reagent comprising six distinct-sequence peptides, and a mass spectrum (bottom panel) of one of those distinct- sequence peptides which is made up of 5 distinct-mass versions.
• the distinct-sequence peptides are designed to be spaced (relatively) evenly across a standard chromatographic gradient when analyzed, for example, on a C 18 reversed phase column using an
• Figure 2 shows a table of five distinct-mass versions of a peptide sequence and their respective masses (right). An exemplary mass spectrum for these peptides is provided (left). In some embodiments, mass spacing of 7-10 Daltons is provided, allowing for spacial resolution in both high and low-resolution MS instruments. In order to achieve this mass differentiation (i.e. distinct-mass variants) stable, heavy isotopically enriched amino acids are incorporated.
• Figure 3 shows an illustration of an embodiment of the present invention in which distinct-mass versions of a peptide sequence are provided at different concentrations. Because their quantities are precisely known, individual (distinct mass) peptides can be mixed in ratios such that a plot of relative intensity versus the molar amount on column is linear when plotted as the log (fold-difference) of the corrected intensity.
• the lightest peptide i.e. the peptide with only one heavy labeled amino acid
• heavy peptide is 10X lower in concentration, thus giving the desired linear relationship.
• Figure 4 shows an illustration of an embodiment of the invention comprising five distinct-mass versions of each of six distinct-sequence peptides.
• the top panel depicts a chromatogram of the reagent, in which distinct peaks are visible for each of the distinct sequences.
• the lower panel depicts mass spectra for each sequence, in which each distinct mass version is separately identifiable.
• the whole mixture is a 30 peptide mixture, in this embodiment.
• Figure 5 shows graphs depicting the effect of loading time on the binding of the peptides to the LC column.
• Figure 6 shows LC analysis of 5 isotopologue mixes of peptides, demonstrating that each isomeric peptide, regardless of mass, co-elutes from the column.
• Figure 8 shows a graph used to calculate correction factors used for peptide quantification. Correction factors are required to normalize all peak intensities to correct for distribution of naturally occurring, heavy isotopes.
• the correction factor represents the ratio of the monoisotopic m/z intensity to the total isotopic distribution intensity and is used to derive the correct intensity of the ion when all isotopes cannot be fully detected.
• Figure 9 shows a representative mass spectrum of five distinct mass versions of a single peptide sequence. These masses (which are the doubly charged peptides) are easily resolved on unit resolution instruments. This is particularly clear in this example, albeit at high-resolution.
• Figure 10 shows the results of MS analysis of a peptide reagent comprising five distinct-mass versions of each of six distinct-sequence peptides.
• Figure 11 shows linear analysis of the mass spectrum of a reagent comprising five distinct mass versions of a single peptide sequence.
• Figure 12 shows linear analysis of the mass spectrum of a reagent comprising five distinct-mass versions of each of six distinct-sequence peptides.
• Figure 13 shows linear analysis of the mass spectrum of a reagent comprising five distinct-mass versions of each of six distinct-sequence peptides (reversed concentrations from Figure 12).
• Figure 14 shows MS analysis of five distinct mass versions of a single peptide sequence, in which each successively heavier version is present at 10-fold concentration excess over the immediately lighter version.
• Figure 15 shows MS analysis of a reagent comprising five distinct-mass versions of each of six distinct-sequence peptides, in which each successively heavier version of each peptide is present at 10-fold concentration excess over the immediately lighter version.
• Figure 16 shows MS analysis of a reagent comprising five distinct-mass versions of each of six distinct-sequence peptides, in which each successively lighter version of each peptide is present at 10-fold concentration excess over the immediately lighter version.
• Figure 17 shows chromatographic detection of all peptides when spiked into a complex background of a yeast tryptic digest.
• Figure 18 shows the lowest detectable peptide quantity (LDPQ) analysis of a reagent comprising five distinct-mass versions of each of six distinct-sequence peptides in a yeast tryptic digest background (starting concentration 2 frnol). Note that, with this mixture, all of the peptides are detectable down to 200 amol, despite being present in a highly complex mixture.
• Figure 19 shows limit of quantification (LOQ) analysis of a reagent comprising five distinct-mass versions of each of six distinct-sequence peptides in a yeast background (starting concentration of 200 fmol).
• Figure 20 shows limit of quantification (LOQ) analysis of a reagent comprising five distinct-mass versions of each of six distinct-sequence peptides in a yeast background, following a second dilution (starting concentration of 20 fmol).
• LOQ limit of quantification
• Figure 21 shows limit of quantification (LOQ) analysis of a reagent comprising five distinct-mass versions of each of six distinct-sequence peptides in a yeast background, following a second dilution (starting concentration of 2 fmol).
• LOQ limit of quantification
• peptide refers to a polymer compound of two or more amino acids joined through the main chain by peptide amide bonds (— C(0)NH— ).
• polypeptide typically refers to short amino acid polymers (e.g., chains having fewer than 25 amino acids), whereas the term “polypeptide” refers to longer amino acid polymers (e.g., chains having more than 25 amino acids).
• distinct-sequence peptides refers to a group of peptides (e.g., two or more) that can be differentiated from one another by the identity and/or order of their amino acids.
• 'three distinct-sequence peptides' are three amino acid chains that, although possibly sharing other characteristics, each comprise at least one amino acid difference, and possibly many amino acid differences, from each other (e.g.,
• distinct-mass peptides refers to a group of peptides (e.g., two or more) that can be differentiated from one another by mass, even if they cannot be differentiated by sequence.
• “Distinct-mass versions of a peptide” refers to a group of peptides that can be differentiated from one another by mass, even though they cannot be differentiated by amino acid sequence (e.g., peptides have the same amino acid sequence).
• 'three distinct-mass versions of a peptide' are three amino acid chains that, although having the same amino acid sequence, are tagged or labeled (e.g., stable heavy isotope labeled) to have different masses (e.g., LLSLGALEFK, L*LSLGALEFK, and L*L*SLGALEFK; wherein * indicates uniform isotopic labeling of the preceding amino acid).
• isomeric peptides refers to a group of peptides (e.g., two or more) that have the same amino acid sequence. The peptides do not differ in terms of tags or chemical modifications, but typically contain varying degrees of stable, heavy isotope
• a pair of isomeric peptides may differ in the number
• L*L*SLGA*LEFK (* indicates uniform CI N labeling of the preceding amino acid) are isomeric peptide (they are also 'distinct-mass peptides' and 'distinct-mass versions of a peptide with the sequence LLSLGALEFK).
• the term “heavy,” refers to an isotope of an element that has a higher
• uniformly heavy labeled refers to a molecular entity (e.g., peptide, amino acid, etc.) in which substantially all of one or more elements within the molecular entity are present as a heavy isotope instead of the isotope that is most prevalent at
• uniformly CI N-labelled amino acid is one in which substantially all the carbons and nitrogens (e.g., >95%, >98%, >99%, >99.9%) are present as 13 C instead of 12 C and 15 N instead of 14 N.
• a "heavy labeled peptide" may comprise one or more uniformly heavy labeled amino acids.
• the present invention provides reagents for instrumentation quality control and methods of use thereof.
• sets of peptides or other molecules are provided for evaluating the performance of instruments with mass spectrometry (MS) and/or liquid chromatography (LC) functionalities.
• a QC reagent comprises a set of peptides that can be predictably separated and/or analyzed by LC, MS, or both.
• peptides of reagents provided herein exhibit a broad range of hydrophobicities or other chemical characteristics such that they can be used to probe the entire separation range of an LC instrument.
• peptide reagents provided herein exhibit a broad range of masses such that they can be used to probe the mass/charge (m/z) ratio range of an MS instrument.
• the performance of the analyzing instrument is evaluated. By comparing present and past performance evaluations (e.g., relative to the same peptide reagent), changes in instrument performance can be identified, monitored, and/or recorded over periods of time ranging from days to months.
• the present invention provides reagents comprising two or more distinct-sequence peptides (e.g., 2 sequences, 3 sequences, 4 sequences, 5 sequences, 6 sequences, 7 sequences, 8 sequences, 8 sequences, 10 sequences...15 sequences...20 sequences... 25 sequences... 30 sequences... 50 sequences, or more).
• two or more distinct-sequence peptides e.g., 2 sequences, 3 sequences, 4 sequences, 5 sequences, 6 sequences, 7 sequences, 8 sequences, 8 sequences, 10 sequences...15 sequences...20 sequences... 25 sequences... 30 sequences... 50 sequences, or more.
• reagents comprise three or more distinct-sequence peptides, four or more distinct-sequence peptides, five or more distinct-sequence peptides, six or more distinct- sequence peptides, seven or more distinct-sequence peptides, eight or more distinct-sequence peptides, nine or more distinct-sequence peptides, ten or more distinct-sequence peptides, twelve or more distinct-sequence peptides, fifteen or more distinct-sequence peptides, twenty or more distinct-sequence peptides, etc.
• each peptide sequence of a group of distinct-sequence peptides is of a detectably different hydrophobicity.
• each peptide sequence of a group of distinct-sequence peptides has a unique hydrophobicity (e.g., each peptide is separable from all of the others by LC).
• one or more peptide sequence of a group of distinct-sequence peptides has a unique hydrophobicity (e.g., one or more, but not all, peptides are separable from all of the others by LC).
• the differences in hydrophobicity can be detected by liquid chromatography (e.g., high performance liquid chromatography (HPLC)).
• HPLC high performance liquid chromatography
• each distinct- sequence peptide results in a chromatography peak that is distinguishable from the peaks of the other distinct-sequence peptide.
• the distinct-sequence peptides span a hydrophobicity range such that they can all be distinguished (e.g., separated) on a single run through a LC column.
• distinct-mass versions of a peptide are provided.
• two or more distinct-mass, same-sequence peptides are provided.
• distinct-mass versions of the same peptide sequence comprise different isotopic labeling.
• distinct-mass versions of the same peptide sequence may comprise different degrees of heavy isotope labeling.
• all, or a portion of, the amino acids in a peptide comprise amounts above natural abundance levels of
• heavy isotopes e.g., H, 1J C, 1J N, 10 0, etc.
• same sequence peptides have different masses based on the degree of heavy isotope labeling of all or a portion of their amino acids (e.g., all amino acids in a peptide at natural abundance, all amino acids in a peptide 25% 13 C/ 15 N-labelled, all amino acids in a peptide 50% 13 C/ 15 N-labelled, all amino acids in a peptide 75% 13 C/ 15 N-labelled, all amino acids in a peptide >99% 13 C/ 15 N-labelled, etc.).
• same-sequence peptides have different masses based on the
• Mass-tags and other labels or modifications may also be employed to alter the mass of peptides without changing the amino acid sequence.
• two or more distinct-mass versions of a single peptide sequence are provided.
• two or more (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) distinct-mass versions of each of a plurality (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) of distinct-sequence peptides are provided.
• the distinct-mass versions of a peptide are not distinguishable by liquid chromatography (e.g., all distinct-mass versions of a peptide elute from a chromatography column (e.g., HPLC column) in a single peak).
• all distinct-mass versions of a peptide sequence exhibit substantially identical hydrophobicity.
• isomeric peptides have identical or substantially identical hydrophobicities and elute from a chromatography column (e.g., HPLC column) in a single peak.
• a set e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, or more
• each isomer has the same or substantially the same hydrophobicity and co-elutes from liquid chromatography (e.g., HPLC).
• each isomer contains a distinct pattern (e.g., different
• a distinct-mass isomer in a set is provided at any suitable concentration (e.g., 10 pM. .. 100 pM. .. I nM. .. 10 nM. .. 100 nM. .. 1 ⁇ . .. 10 ⁇ . .. 100 ⁇ ).
• Distinct-mass isomers may be of unique concentrations or may be at the same concentration as one or more other distinct-mass peptides of the same set.
• each distinct-mass isomer in a set is provided at the same concentration (e.g., 10 pM... 100 pM... 1 iiM... 10 iiM... 100 iiM... 1 ⁇ ... 10 ⁇ ...
• each distinct-mass isomer in a set is provided at a different concentration (e.g., a set of five distinctly-massed isomers provided at 1 iiM, 10 iiM, 100 iiM, 1 ⁇ , and 10 ⁇ , respectively).
• the present invention provides two or more (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) distinct-sequence sets of two or more (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) distinct-mass isomeric peptides.
• Table 1 depicts generic peptides comprising six distinct-sequence sets (sequences A-F) of four distinct-mass versions each (0, 1, 2, or 3 labeled amino acids).
• the distinct-sequence peptides of a reagent may each be present as the same number of distinct- mass versions (as depicted in Table 1). In other embodiments, two or more distinct-sequence peptides of a reagent comprise different numbers of distinct-mass versions.
• Table 2 depicts an embodiment of the invention which comprises six distinct sequence sets (VTSGSTSSR (SEQ ID NO: 1), LASVSVSR (SEQ ID NO: 2),
• YVYVADVAAK (SEQ ID NO: 3), VVGGLVALR (SEQ ID NO: 4), LLSLGAGEFK (SEQ ID NO: 5), LGFTDLFSK (SEQ ID NO: 6)) of six distinct mass isomeric peptides each.
• Table 2 Exemplary distinct-sequence sets of distinct-mass isomeric peptides.
• the distinct-sequence sets exhibit varying degrees of hydrophobicity, and therefore each set elutes independently when analyzed by liquid chromatography (e.g., HPLC).
• Each distinct-mass isomer of a distinct-sequence set has the same hydrophobicity, and therefore co-elute when analyzed by liquid chromatography (e.g., HPLC).
• Any other suitable combinations of distinct-sequence sets of distinct-mass isomers are within the scope of the present invention.
• the invention is not limited by the length, sequence, number, or labeling of the peptides.
• peptides within a set of distinct sequence peptides are selected based on criteria including, but not limited to: peak intensity, peak width, peak compactness (narrowness), LC retention time (e.g., not overlapping with another peptide in the reagent), absence of excluded amino acids (e.g., P, M, W, C, N, Q, and/or N-terminal E) which are deemed to contribute to product instability, feasibility of incorporating sufficient number (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) of stable, isotope labeled amino acids (e.g., commercially available stable isotope labeled amino acids), stability, ease of achieving high degree (e.g., >90%, >91%, >92%, >93%, >94%, >95%, >96%, >97%, >98%, >99%) of purity, etc.
• peptides comprise one or more uniformly isotopically
• a reagent e.g., peptide mixture
• methods of use thereof for the validation, calibration, performance assessment, and/or performance monitoring of analytic instruments (e.g., liquid chromatographs with UV and/or MS detection).
• a reagent provides a performance meter that is used to monitor instrument performance. Reagents and methods provide: assessment of initial instrument performance, monitoring of instrument history, comparison of parameters between instruments, validation of instrument performance (e.g., before or after use), etc.
• a reagent comprises a plurality (e.g., 5) of distinct-sequence sets of several (e.g., 5) distinct-mass isomeric peptides each.
• the reagent is analyzed by liquid chromatography, which separates each of the distinct-sequence sets from each other by their different hydrophobicities.
• the reagent is subsequently analyzed by mass spectrometry, which characterizes the distinct-mass isomers within each set by their mass-to-charge ratios.
• the mass differences e.g., 3-5 Daltons
• the different isomers within a set are provided at a range of different concentrations.
• concentration differences among the isomers within each set are apparent based on the MS analysis and/or amino acid analysis.
• analysis of a single reagent by both the LC and MS components of an instrument provides simultaneous performance analysis.
• a reagent is first analyzed by LC and then analyzed by MS.
• a reagent is analyzed by LC and MS simultaneously (e.g., two portions of the same reagent are each subjected to analysis by one technique).
• each distinct-mass version of a peptide sequence is the same concentration. In some embodiments, each distinct-mass version of a peptide sequence is a different concentration. In some embodiments, the distinct-mass versions of a peptide sequence are provided at a range of concentrations. In particular embodiments, the distinct- mass versions of each peptide sequence in a reagent are provided at the same range of concentrations. In some embodiments, each distinct-sequence peptide (e.g. the sum of the distinct-mass version of the same peptide sequence) is provided at the same concentration.
• each distinct-sequence peptide (e.g. the sum of the distinct-mass version of the same peptide sequence) is provided at a unique concentration.
• the distinct-sequence peptides (e.g. the sum of the distinct-mass version of the same peptide sequence) are provided at range of concentrations (e.g., linear or non-linear distribution over a range).
• a reagent comprises buffers, solvents, salts, and/or other additives (e.g., marker (e.g., radiolabel, fluorescent dye, chromophore, mass tag, etc.), etc.) suitable for use in LC and/or MS.
• Reagents may comprise any suitable buffer (e.g., suitable for use in both LC and MS), such as Ammonium Bicarbonate, Triethyl ammonium bicarbonate (TEAB), TAPS, Tris, HEPES, TAE, TES, MOPS, MES, phosphate buffer, citric acid, CHES, acetic acid, borate, etc.
• a reagent comprises additives to promote solubility (e.g., urea, guanidine HCL, detergents, sugars etc.), stability, etc. of the peptides within the reagent.
• a reagent comprises one of more solvents, such at acetonitrile, methanol, ethanol, hexane, chloroform, etc.
• the methods and reagents find use in quality control of any suitable analytic instruments (e.g., LC, HPLC, MS (e.g., Atmospheric Pressure Ion sources (API), Electrospray or nebulization assisted Electrospray (ES), Atmospheric Pressure Chemical Ionization (APCI), Matrix Assisted Laser Desorption Ionization (MALDI), etc.), LC-MS, LC-MS/MS etc.).
• a reagent is selected, prepared, and/or configured for use with a specific type of instrument (e.g., LC, MS, LC-MS, or LC-MS/MS).
• a reagent is specifically selected, prepared, and/or configured to be used with a variety of instruments.
• a reagent is selected, prepared, and/or configured for performing specific quality control assessments (e.g., calibration, performance evaluation, system suitability, etc.).
• the data generated by analysis (e.g., LC, MS, etc.) of a reagent is analyzed manually by a user or a trained specialist.
• software and/or a package of software is provided to perform automated characterization of the reagent analysis.
• software analyzes and reports on LC parameters (e.g., peak separation, peak efficiency, peak height, peak width, peak shape, retention time, etc.) and/or MS parameters (e.g., mass accuracy, mass resolution, sensitivity, dynamic range and sampling and/or isolation efficiency).
• software correlates peaks in an LC and/or MS analysis to peptides and/or peptide isomers in the reagent.
• software draws conclusions about instrument performance based on
• software compares reagent analyses performed at different time points (e.g., separated by minutes, hours, days, weeks, years, etc.) to monitor changes in instrument performance.
• software calibrates instrument data display/output to offset changes in instrument performance over time.
• the software utilizes identifiers for the individual peptides, peptide mix, and/or reagent being analyzed in data analysis.
• the software correlates the data with the known physical characteristics of the individual peptides, peptide mix, and/or reagent.
• software analysis automatically makes determinations regarding instrument sensitivity and/or dynamic range.
• the software will report on instrument performance history.
• the software report on a comparison of performance between multiple instruments.
• the software generates a performance score.
• kits are provided that comprise a peptide reagent and one or more of additional reagents, software, container(s), instructions, additional peptide reagent, etc.
• suitable aliquots of a peptide reagent are provided in a tube or other suitable container.
• a kit provides multiple quality control reagents, useful for performing multiple quality control procedures.
• Peptides were derived from a collection of tryptic peptides originating from a human plasma sample that had been depleted of albumin and IgG. Analysis of the data facilitated the identification of approximately 8300 unique peptides. Peptides containing W, M, C, P, N, Q, and N-terminal E/D were removed from consideration due to stability concerns. Peptides containing histidine were not considered since they added additional charge to the peptides. Furthermore, only fully tryptic peptides were considered (those with internal lysines and arginines were removed from consideration). Further, only peptides that had the ability to incorporate up to at least 7 stable isotopically-labeled residues and could allow for a mass difference of at least 4 Daltons per variant were selected for further consideration.
• Peptides were grouped into 6 bins based on retention times. A set of approximately 20 peptides per bin were then selected based on signal intensity. These peptides were
• final peptide candidates were required to be detectable over a very large dynamic range, sensitive limit of detection and good chromatographic peak shape.
• each of the final peptide candidates was required to contain at least 7 amino acids that could facilitate the isotopic incorporation of stable, heavy isotopically-labeled amino acids that would provide variants with mass differences of at least 4 Daltons between each other such that all 5 peptide isomers within the sample could be clearly resolved so that an accurate measurement of the peak area of all isotopes within the peptide envelope could be measured and integrated.
• peptides with stable, heavy isotopes (uniform CI N labeling).
• the following amino acids were required for various peptides (see Table 4 below) with the number in parenthesis indicating the mass shift in Daltons: (V, +6), (T, +5), (S, +4), (L,+7), (A, +4), (K,+8), (R,+10), (F, +10).
• the peptides were subjected to amino-acid analysis so the precise molar amount could be determined.
• a mixture of 30 peptides was prepared in 2 formats (See Table 5). Both formats contained the same set of 6 peptides with each peptide having a set of 5 isomeric variants (30 peptides total).
• the isomers were identical in sequence, but contained different heavy labeled amino acids so that they would be distinguished by differing masses. These masses were used to generate standard curves so as to determine instrument sensitivity and dynamic range. The specific details of the variants and mixtures are given in Table 5 below. Format number 1 consisted of peptides in which each set of identical sequence (but variable with regard to isomer and mass) would differ by a 10-fold difference (either increasing or decreasing amount) of peptide amount. Format 2 was similar to format 1 with the exception that the decrease from one mass to the next is a 3-fold decrease. Figure 16 provides an example of what the 6 standard curves would look like after correction for peak intensities. Additionally, all peptides contained at least one labeled amino acid to prevent isobaric interference when analyzing samples from human plasma, etc.
• the peptides (30 total) were mixed into a solution and 200 fmol of this solution was loaded onto a Cig capillary LC Column (75 ⁇ x 15 cm).
• the LC gradient typically 1 hour, was ramped from 2.5% buffer B (Buffer A - 0.1% formic acid in water and Buffer B - acetonitrile/0.1% FA) until 40 % B.
• Mass spectra were collected, in real time, immediately after following LC. All mass spectra were collected on either a Thermo LTQ-Orbitrap Velos or Q Exactive mass spectrometer operating at MS resolutions of 60,000 with calibrated mass accuracies below 3 ppm. Samples were acquired with a mass range of 350-1200 m/z such that multiply charged (+2/+3) peptides would trigger MS/MS scans.
• the peptides of Table 4 were analyzed by LC and MS, both in the formats described in Table 5 and in other combinations (e.g., isotopologue mixes (e.g., the lightest version of each peptide sequence, second lightest of each peptide sequence. .. heaviest version of each peptide sequence)), to assess, for example peptide characteristics and analysis procedures.
• isotopologue mixes e.g., the lightest version of each peptide sequence, second lightest of each peptide sequence. .. heaviest version of each peptide sequence
• the effect of loading time on the binding of the peptides to the LC column was examined (See Figure 5). It was determined that shorter loading times (e.g., 2.5 min) were preferential for the binding of all of the peptides, in particular the most hydrophilic sequence (VTSGSTSTSR).
• Figure 6 depicts an LC analysis of sotopologue mixes (e.g., the lightest version of each peptide sequence, second lightest of each peptide sequence... heaviest version of each peptide sequence) of the peptides of Table 4.
• Mix #1 consisted of the "lightest” peptide only from each set, and each mix was prepared with a progressively heavier variant.
• mix #5 contained the "heaviest” form of each peptide.
• the data indicate that although the peptides contain different types of stable, heavy labeled amino acids, they are chemically identical (See Figure 6).
• Mass spectra were taken of the various peptide sequences (See, e.g., Figure 9).
• each different mass version of the peptide sequence was supplied at equal concentration.
• approximately equal intensities were observed, with mass separations of at least7 Daltons (note that we are observing the doubly charged peptides and thus have m/z spacings of 3.5 Daltons, respectively).
• All 30 of the peptides of Table 4 were analyzed by MS in an equimolar mixture.
• the molar amounts of each of the peptides (200 frnole) are plotted versus the log of the corrected signal intensity ( Figure 10).
• the peptides when mixed equally, give equal intensities as predicted.

Landscapes

• Physics & Mathematics (AREA)
• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
• Peptides Or Proteins (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (2)

Family

ID=51350143

Family Applications (1)

Country Status (4)

Cited By (3)

Families Citing this family (4)

Family Cites Families (23)

• 2014
  • 2014-02-13 US US14/180,125 patent/US10247711B2/en active Active
  • 2014-02-13 WO PCT/US2014/016289 patent/WO2014127144A2/en not_active Ceased
  • 2014-02-13 JP JP2015558133A patent/JP6396337B2/ja active Active
  • 2014-02-13 EP EP23194018.0A patent/EP4290231A3/en active Pending
  • 2014-02-13 EP EP14751839.3A patent/EP2956768B1/en active Active
• 2018
  • 2018-08-29 JP JP2018159973A patent/JP6563574B2/ja active Active
• 2019
  • 2019-02-14 US US16/275,417 patent/US10900939B2/en active Active
  • 2019-08-23 US US16/549,769 patent/US10908135B2/en active Active
• 2021
  • 2021-01-27 US US17/159,923 patent/US11692983B2/en active Active

Also Published As

Similar Documents

Legal Events