BR112014015947B1 - DIPEPTIDE COMPRISING A NON-PROTEOGENIC AMINO ACID AND METHOD FOR OBTAINING A FINAL POLYPEPTIDE OR PROTEIN - Google Patents

Abstract

DIPEPTIDE COMPRISING A NON-PROTEOGENIC AMINO ACID. The present invention relates to a dipeptide comprising a non-proteogenic amino acid, methods of making such and methods of using said dipeptide in a process of making a polypeptide or protein comprising one or more non-proteogenic amino acids.

Description

Technical Field

[001] The present invention relates to a dipeptide comprising a non-proteogenic amino acid, methods of making such and methods of using said peptide for producing a polypeptide or protein comprising one or more non-proteogenic amino acids.

background

[002] A large number of polypeptides and proteins have been approved for use in medical practice. Polypeptides and proteins can be produced in suitable host cells by recombinant DNA technology or they can be produced synthetically by well-established peptide synthesis technology. However, natural polypeptides and proteins tend to exhibit high clearance rates that are unacceptable for many clinical indications where a high plasma concentration of the polypeptide is required for an extended period of time.

[003] Natural polypeptides and proteins can be altered from the natural form to analogues and derivatives thereof to change or enhance certain characteristics. For example, non-proteogenic amino acids (ie, unnatural amino acids) can be added or substituted in polypeptides or proteins to, for example, confer some protection against hydrolysis (such DPP-IV hydrolysis of GLP-1 peptides).

[004] Polypeptides containing one or more non-proteogenic amino acids such as N-terminally modified GLP-1 analogues can be prepared by introducing non-proteogenic amino acid(s) through chemical synthesis in a stepwise manner in which a coupling step followed by a deprotection step is applied for each amino acid to be added to the polypeptide or protein.

[005] The stepwise synthesis is therefore time consuming and inconvenient, it can lead to the formation of many by-products, intermediate purification steps may be necessary and may result in a significant amount of racemization of some amino acid residues such as histidine residues.

[006] Alternatively, a peptide fragment including the non-proteogenic amino acid(s) can be coupled to the remaining polypeptide or protein where the fully protected fragment, such as, for example, a fragment protected at the N-terminal amino group and the side chain amino groups, is used in the method.

[007] Such a peptide fragment cannot, however, be soluble in aqueous media limiting its use. Furthermore, multiple deprotection steps are required if orthogonal protecting groups are present on the fragment, and if isolated, intermediate purifications may be required between synthetic steps, and intermediate isolation problems may occur.

[008] WO 2009/083549 relates to a method for preparing GLP-1 analogues and derivatives containing non-proteogenic amino acids. WO 2007/147816 A1 and WO 2010/125079 A2 patent applications relate to the synthetic coupling of peptide fragments. Bourgault, S. et al. describe in PEPTIDES, vol. 29, no. 6(1), June 2008, pages 919-932 the use of conventional peptide chemistry.

[009] A peptide fragment for use in an improved method for obtaining polypeptides containing one or more non-proteogenic amino acids is still needed.

summary

[010] The present invention relates to a dipeptide of Chemical Formula 1: wherein R1 is H or an amino protecting group, and R2 is an amino protecting group; or R1 is a leaving alkyl group, and R2 is H or a leaving alkyl group; or R1 and R2 are together forming a ring; R3 is H, or a secondary ammonium cation, a tertiary ammonium cation, or a metal cation forming a salt as the carboxylate group; and R4 is absent or an acidic salt.

[011] Also, a method is contemplated for producing a dipeptide of the invention.

[012] Furthermore, a method for obtaining a polypeptide or protein comprising one or more non-proteogenic amino acids is described, in which the method comprises a step of reacting a dipeptide of the invention with a polypeptide or protein.

[013] The invention can also solve other problems that will be apparent from the disclosure of exemplary embodiments.

Description

[014] The present invention relates to a dipeptide comprising a non-proteogenic amino acid, wherein the dipeptide is suitable for coupling to a polypeptide or protein.

[015] In one aspect, the dipeptide of the invention has a free unprotected imidazolyl moiety. In one aspect, the dipeptide of the invention is in the form of a carboxylic acid salt.

[016] In one aspect of the invention, the dipeptide is of Chemical Formula 1: Chemical Formula 1 wherein R1 is H or an amino protecting group such as but not limited to Boc, Trt, Bpoc, Fmoc, Nsc, Cbz, Alloc, oNBS, pNBS, dNBS, ivDde or Nps, and R2 is an amino protecting group such as but not limited to Boc, Trt, Bpoc, Fmoc, Nsc, Cbz, Alloc, oNBS, pNBS, dNBS, ivD de or Nps; or R1 is a leaving alkyl group such as, but not limited to benzyl or tert-Butyl, and R2 is H or a leaving alkyl group such as, but not limited to, benzyl or tert-Butyl; or R1 and R2 are together forming a ring such as, inter alia, fatalimide or 1,3,5-dioxazine; R3 is H, or a secondary ammonium cation, a tertiary ammonium cation or a metal cation, such as an alkali metal cation or an alkaline earth metal cation, forming a salt with the carboxylate group; and R4 is absent or an acidic salt such as, but not limited to, a TFA, HCl, HBr or hydrogen sulfate salt.

[017] In one aspect of the invention, R1 is H and R2 is an amino protecting group such as, but not limited to, Boc, Trt, Bpoc, Fmoc, Nsc, Cbz, Alloc, oNBS, pNBS, dNBS, ivDde or Nps; or R1 and R2 are together forming a ring such as, inter alia, fatalimide or 1,3,5-dioxazine; or R1 is a leaving alkyl group such as, inter alia benzyl or tert-Butyl and R2 is H or a leaving alkyl group such as, inter alia benzyl or tert-Butyl.

[018] In one aspect, R1 is H and R2 is a base-sensitive protecting group such as, but not limited to, Fmoc. In one aspect, R1 is H and R2 is Fmoc.

[019] When used herein, the term "amino protecting group" should be understood as a protecting group (alternative term: protecting group) known to the person skilled in the art of peptide chemistry which is introduced into the dipeptide by chemical modification of an amine (functional) group in order to prevent reaction on the same amine during a chemical reaction.

[020] When used herein, the term "removable alkyl group" shall be understood to mean an alkyl group, such as, but not limited to, a benzyl group, which can be removed through catalytic hydrogenolysis methodology. In one aspect of the invention, R1 is benzyl and R2 is H.

[021] R3 may be hydrogen, a secondary ammonium cation, a tertiary ammonium cation, or a metal cation, wherein the secondary ammonium cation, tertiary ammonium cation, or metal cation forms a salt with the carboxylate group to which it is adjacent. In one aspect of the invention, the metal cation is an alkali metal cation or an alkaline earth metal cation. In one aspect, R3 is selected from the group consisting of: H, lithium cation, sodium cation, potassium cation, cesium cation, calcium cation, magnesium cation, a cation derived from a secondary amine such as, but not limited to, N,N-dicyclohexyl ammonium cation, N,N-ditert-butyl ammonium cation, or a cation derived from a tertiary amine such as, but not limited to, triethylammonium cation.

[022] In one aspect of the invention, R3 is H. In one aspect, R3 together with the carboxylate group to which it is adjacent forms a salt, such as, but not limited to, a monovalent salt, a bivalent salt, or a salt derived from an amine.

[023] According to one aspect of the invention, R3 may be a secondary ammonium cation, a tertiary ammonium cation or a metal cation, such as an alkali metal cation or an alkaline earth metal cation, forming a salt with the carboxylate group to which it is adjacent. The salt between R3 and the carboxylate group may be, for example, a monovalent salt such as, but not limited to, an alkaline salt including a lithium salt, a sodium salt, a potassium salt, or a cesium salt, a bivalent salt such as, but not limited to, a calcium salt or a magnesium salt, a salt derived from a secondary amine such as, but not limited to, N,N-dicyclohexylamine or N,N-ditert-butylamine, or a salt derived from a tert amine such as but not limited to triethylamine.

[024] It was surprisingly discovered by the inventors that the dipeptide of the invention where R3 is H, or is a secondary ammonium cation, a tertiary ammonium cation or a metal cation that has been a salt with the carboxylate group to which it is adjacent, and R4 is absent or an acidic salt is particularly good in, for example, an aqueous acylation reaction where the dipeptide is reacted with a peptide or polypeptide.

[025] In one aspect of the invention, R4 is absent. In one aspect, R4 is an acidic component forming a salt with the dipeptide. In one aspect, R4 is selected from the group consisting of: TFA, HCl, HBr and hydrogen sulfate. In one aspect R4 is TFA.

[026] In one aspect, the dipeptide of the invention is the enantiomeric or racemic dipeptide Fmoc-His-Aib-OH of Chemical Formula 2 Chemical Formula 2 where * indicates the chiral center of the dipeptide and R4 is absent or an acidic component such as but not limited to TFA, HCl, HBr or hydrogen sulfate, said acidic component forming a salt with the dipeptide. In one aspect R4 is TFA.

[027] Here, the term "enantiomeric" in a sample of compounds should be understood as an excess of one enantiomeric form, that is, either the L or the D form, in the sample. When used herein, the term "racemic" is to be understood as equivalent amounts of L and D form in a sample of compounds. As a non-limiting example, the histidine residue of enantiomeric Fmoc-His-Aib-OH of Chemical Formula 2 can be in the form of L-histidine or D-histidine.

[028] In one aspect of the invention, the dipeptide of Chemical Formula 1 or Chemical Formula 2 is activated by an activating agent known to a person skilled in the art. In one aspect, the dipeptide of Chemical Formula 1 or Chemical Formula 2 is activated by a phosphonium-based coupling reagent. In one aspect, the phosphonium-based coupling reagent is selected from the group consisting of: Benzotriazol-1-yl-oxy-tris-(dimethylamino)-phosphonium hexafluorophosphate (BOP), (Benzotriazol-1-yloxy)tripyrolidinophosphonium hexafluorophosphate (PyBOP), (7-Azabenzotriazol-1-yloxy) tripyrolidinophosphonium hexafluorophosphate (PyAOP), hexa 6-Chloro-benzotriazol-1-yl-oxy-tris-pyrrolidinophosphonium fluorophosphate (PyClocK), O-[(1-cyano-2-ethoxy-2-oxoethylidene)amino]-oxytri(pyrrolidin-1-yl)phosphonium hexafluorophosphate (PyOxP), O-[(1-cyano-2-ethoxy-2-oxoethylidene)amino]-oxo tetrafluoroborate tri(pyrrolidin-1-yl)phosphonium (PyOxB). In one aspect, the phosphonium-based coupling reagent is (benzotriazol-1-yloxy)tripyrolidinophosphonium hexafluorophosphate (PyBOP).

[029] The term "phosphonium-based coupling reagent" should be understood here as a coupling reagent containing a phosphonium salt that, when reacted in situ with a carboxylic acid, forms an activated carboxylic acid to be reacted with a polypeptide or protein.

[030] The dipeptide of the invention is surprisingly stable and has a long shelf life.

[031] When used herein, the term "stabilized" or "stable" when referring to a dipeptide of the invention refers to the dipeptide with increased chemical stability, increased physical stability, or increased physical and chemical stability.

[032] In one aspect, a dipeptide of the invention is stable for more than 6 weeks of use and for more than 2 years of storage. In another aspect, a dipeptide of the invention is stable for more than 4 weeks of use and for more than two years of storage. In a further aspect, a dipeptide of the invention is stable over 4 weeks of use and over 3 years of storage. In yet another aspect, a dipeptide of the invention is stable over 2 weeks of use and over 1 year of storage.

[033] When used herein, the term "ambient temperature" means the temperature of the surroundings. Under indoor conditions, the ambient temperature is the same as the ambient temperature and can be, for example, 25°C.

[034] The dipeptide of the invention is easy to handle and its use in peptide chemistry is easy compared to conventional step-by-step solid phase peptide synthesis due to the reduced amount of chemical modification steps, such as deprotection and activation steps.

[035] According to one aspect, the dipeptide of the invention can be used in a method for obtaining a polypeptide or protein comprising one or more non-proteogenic amino acids.

[036] In one aspect, the dipeptide according to the invention is used in a process for covalently coupling the dipeptide to a polypeptide or protein. In one aspect, the dipeptide is used in a process for coupling the dipeptide to the N-terminal amine of a polypeptide or protein. In one aspect, the dipeptide is used in a process for coupling the dipeptide to nucleophiles in other molecules that do not belong to the chemical group of polypeptides and/or proteins.

[037] In one aspect, the polypeptide or protein to which the dipeptide is coupled consists of proteogenic amino acids, that is, the polypeptide or protein to which the dipeptide is coupled does not comprise any non-proteogenic amino acids.

[038] In one aspect of the invention, the dipeptide of Chemical Formula 1 or Chemical Formula 2 is used to couple said dipeptide to a polypeptide or protein to form an amide bond between the carboxylate group of the dipeptide of Chemical Formula 1, i.e., the R3-containing functional group, or the carboxylic acid of Chemical Formula 2 and a free amine of the polypeptide or protein. In one aspect, the dipeptide of Chemical Formula 1 or Chemical Formula 2 is reacted in a polypeptide or protein in an aqueous medium to form an amide bond between the carboxylic acid of the dipeptide of Chemical Formula 1 or Chemical Formula 2 and the N-terminal amine of a polypeptide or protein.

[039] According to one aspect of the invention, R1 and/or R2 is removed upon completion of the reaction with a polypeptide or protein. In one aspect, R1 and/or R2 is removed in a chemical step. In one aspect, R1 and/or R2 is removed in a deprotection step under basic conditions. In one aspect, R1 and/or R2 is removed in a deprotection step comprising adding the base to the reaction medium. In one aspect, R1 and/or R2 is removed in a deprotection step comprising adding an amine to the reaction medium. In one aspect, R1 and/or R2 is removed in a deprotection step comprising adding piperidine to the reaction medium.

[040] In one aspect of the invention, R1 and/or R2 is removed in situ in a chemical step after completion of the acylation reaction with a polypeptide or protein.

[041] According to one aspect, the dipeptide of the invention can be used in a method for obtaining a polypeptide or protein comprising one or more non-proteogenic amino acids. In one aspect, the reaction is carried out in solution. In one aspect, the activated dipeptide of the invention is reacted with a polypeptide or protein dissolved in an aqueous medium. In one aspect, the coupling reaction is performed in a solid phase peptide synthesis as known to one skilled in the art. It has been found by the inventors that by using said method to obtain a polypeptide or protein comprising one or more non-proteogenic amino acids and a histidine N-terminally therein, a polypeptide or protein product is obtained in which the histidine residue is not or only slightly racemized.

[042] In one aspect, the method for obtaining a polypeptide or protein comprising one or more non-proteogenic amino acids comprises the following steps: Activation of the dipeptide with a phosphonium-based coupling reagent Reaction of the activated dipeptide with a polypeptide or protein Removal of the protecting group(s) in situ By which the final polypeptide or protein is obtained.

[043] In one aspect, the method for obtaining a polypeptide or protein comprising one or more non-proteogenic amino acids comprises the following steps: Activation of the dipeptide of Chemical Formula 1 or Chemical Formula 2 with a phosphonium-based coupling reagent Reaction of the activated dipeptide with a polypeptide or protein Removal of the protecting group(s) in situ By which the final polypeptide or protein is obtained.

[044] In one aspect, the activated dipeptide is reacted with a polypeptide or protein in an aqueous medium. As used herein, the terms "aqueous medium" or "aqueous media" include any water-based medium, for example, water, saline, a sugar solution, a transfusion solution, a buffer, and any other readily available water-based medium. In addition, aqueous media may contain one or more water-soluble organic solvents such as, but not limited to, dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP), dimethylacetamide (DMAC), dimethyl sulfoxide (DMSO), acetonitrile, dioxane, a water-soluble acetal such as, for example, dimethyl acetal, diethyl acetal or 1,3-dioxalan and a soluble alcohol. in water such as, for example, methanol, ethanol, propanol, 2-propanol and butoxy-2-ethanol.

[045] In one aspect, the aqueous media in which the activated dipeptide is reacted with a polypeptide or protein comprises from 100 to 10% water and thus from 0 to 90% of the other solvent(s), where non-limiting examples of other solvents, for example, may be selected from the group consisting of DMF, NMP, DMAC, DMSO, acetonitrile, dioxane, a water-soluble acetal such as, for example, dimethyl acetal, diethyl acetal or 1,3-dioxalan and a water-soluble alcohol such as, for example, methanol, ethanol, propanol, 2-propanol and butoxy-2-ethanol. In one aspect the aqueous media comprises from 80 to 20% water, such as 60 to 30% water. In one aspect, the aqueous media comprises from 50 to 30% water. In one aspect, the aqueous media comprise about 50% water. In one aspect, the aqueous media comprise about 40% water. In one aspect, the aqueous media comprises about 30% water.

[046] In one aspect of the invention, the dipeptide is dissolved in an aprotic organic solvent or a mixture thereof, such as, but not limited to, DMF, NMP, DMAC, DMSO, acetonitrile and dioxane, before being added to the aqueous media in which it is reacted with a peptide or polypeptide.

[047] When used herein, the term "aprotic" is used for solvents such as, for example, acetone or dichloromethane that tend to have large dipole moments, i.e. separation of partial positive and partial negative charges within the same molecule, and positively charged solvate species across their negative dipole. Examples of aprotic solvents include, but are not limited to, dichloromethane (DCM), tetrahydrofuran (THF), ethyl acetate, acetone, DMF, NMP, DMAC, DMSO, acetonitrile, dioxane and propylene carbonate.

[048] In one aspect, the activated dipeptide is reacted with a solid phase polypeptide or protein using a procedure known to one skilled in the art of peptide chemistry, as, for example, described in ISBN 0-7167-7009-1 "Synthetic Peptides", ed. Gregory A. Grant.

[049] In one aspect, the phosphonium-based coupling reagent is PyBOP. In one aspect, the protecting group is Fmoc. In one aspect, the final polypeptide or protein is obtained in solution.

[050] In one aspect, the protecting group is removed under basic conditions. In one aspect, the protecting group is removed at a pH that is at least 7. In one aspect, the protecting group is removed by piperidine, DBU (1,8-diazabicycloundec-7-ene) or tert-butylamine.

[051] In one aspect of the invention, the pH of the aqueous reaction mixture in the acylation step is adjusted between pH 7 and pH 14. In one aspect, the pH of the reaction medium is between pH 8 and pH 13. In another aspect, the pH is between pH 8 and pH 12. In another aspect, the pH is between pH 8 and pH 10. In another aspect, the pH is between pH 8.3 and pH 9.7.

[052] The "reaction mixture" should be understood here as the mixture of solvents and reagents used when reacting the dipeptide of the invention with a polypeptide or protein. The reaction mixture may be aqueous, i.e., water being present in the reaction mixture.

[053] The pH of the reaction mixture can be controlled by means known to the person skilled in the art. For example, a simple pH indicator paper test (pH stick) or a pH meter can be used to measure the pH and acid or base can be added manually to adjust the pH, or a pH meter with a feedback mechanism, which can control the pH of the solution, can be used.

[054] Suitable acids for pH adjustment include, but are not limited to: Hydrochloric acid, sulfuric acid, hydrogen sulfate, phosphoric acid, citric acid, and acetic acid.

[055] Suitable bases for pH adjustment include, but are not limited to: tertiary amine bases such as, but not limited to, triethylamine or diisopropylethylamine, N-methylmorpholine, alkali metal hydroxides such as, but not limited to, lithium hydroxide, sodium hydroxide, potassium hydroxide or cesium hydroxide, and alkaline carbonates such as, but not limited to, potassium carbonate, sodium carbonate, lithium carbonate, potassium hydrogen carbonate, sodium hydrogen carbonate or lithium hydrogen carbonate.

[056] In one aspect of the invention, the reaction mixture comprises a buffer. In one aspect of the invention, the buffer is selected from the group consisting of: phosphate buffer, sodium carbonate buffer, Bicine N,N-Bis(2-hydroxyethyl)glycine buffer, HEPPS buffer (3-[4-(2-Hydroxyethyl)-1-piperazinyl]propanesulfonic acid buffer), HEPES buffer (4-(2-Hydroxyethyl)-1-piperazineethanesulfonic acid buffer) sonic buffer), MOPS buffer (3-(N-Morpholino)propanesulfonic acid buffer) and TEA buffer (triethylamine buffer). In one aspect of the invention, the reaction mixture comprises a TEA buffer (triethylamine buffer).

[057] Before addition to the reaction mixture, the dipeptide can be activated, that is, the carboxylic acid functionality of the dipeptide can be converted into an activated ester of said carboxylic acid. When activating the dipeptide of the invention, the temperature of the reaction mixture during the activation step can be between -5 °C and 50 °C as well as between 0 °C and 50 °C. In one aspect, the temperature is between 5°C and 40°C. In another aspect, the temperature is between 10°C and 35°C. In a further aspect, the temperature is between 15 and 25 °C. In yet a further aspect, the temperature is about 20°C during the activation step.

[058] The temperature of the reaction mixture during the acylation step, where the activated dipeptide of the invention is reacted with a polypeptide or protein, can be between -5°C and 50°C such as between 0°C and 50°C. In one aspect, the temperature is between 5°C and 40°C. In another aspect, the temperature is between 10°C and 35°C. In a further aspect, the temperature is between 15 and 25°C. In yet a further aspect, the temperature is about 20°C.

[059] The term "polypeptide or protein", as used herein, means a compound of at least two constituent amino acids connected by polypeptide linkages. The constituent amino acids can be chosen from the group of amino acids encoded by the genetic code (proteogenic amino acids) and they can be natural amino acids that are not encoded by the genetic code, as well as synthetic amino acids (non-proteogenic amino acids). The 22 proteogenic amino acids are: Alanine, Arginine, Asparagine, Aspartic acid, Cysteine, Cystine, Glutamine, Glutamic acid, Glycine, Histidine, Hydroxyproline, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Proline, Serine, Threonine, Tryptophan, Tyrosine and Valine.

[060] Thus, a non-proteogenic amino acid is a moiety that can be incorporated into a polypeptide or protein through polypeptide linkages, but is not a proteogenic amino acid. Examples are Y-carboxyglutamate, ornithine, phosphoserine, the D-amino acids such as D-alanine and D-glutamine. Non-proteogenic synthetic amino acids include amino acids manufactured by chemical synthesis, i.e., D-isomers of amino acids encoded by the genetic code such as D-alanine and D-leucine, Aib (α-aminoisobutyric acid), Abu (α-aminobutyric acid), ornithine, Dap (2,3-diaminoproponic acid), Dab (2,4-diaminobutyric acid), Tle (tert-butylglycine ), 3-aminomethyl benzoic acid, anthranilic acid, des-amino-Histidine, the beta analogues of amino acids such as β-alanine etc. D-histidine, desaminohistidine, 2-aminohistidine, β-hydroxyhistidine, homohistidine, Nα-acetylhistidine, α-fluoromethylhistidine, α-methylhistidine, 3-pyridylalanine, 2-pyridylalanine or 4-pyridylalanine, (1-aminocyclopropyl)carboxylic acid, (1-aminocyclobutyl)carboxylic acid , (1-aminocyclopentyl)carboxylic acid, (1-aminocyclohexyl)carboxylic acid, (1-aminocycloheptyl)carboxylic acid or (1-aminocyclooctyl)carboxylic acid.

[061] The term "analog", as used herein, referring to a polypeptide or protein means a modified polypeptide or protein in which one or more amino acid residues of the polypeptide or protein have been replaced by other amino acid residues and/or in which one or more amino acid residues have been deleted from the polypeptide or protein and/or in which one or more amino acid residues have been deleted from the polypeptide or protein and/or in which one or more amino residues acid were added to the polypeptide or protein. Such addition or deletion of amino acid residues can occur at the N-terminus of the polypeptide or protein and/or at the C-terminus of the polypeptide or protein. A simple system is often used to describe analogues: For example, [Aib8,Arg34]GLP-1(7-37) designates an analogue of GLP-1(7-37) in which the naturally occurring alanine at position 8 is replaced with alpha-aminoisobutyric acid and lysine at position 34 has been replaced with Arginine. All amino acids for which the optical isomer is not indicated should be understood as the L-isomer. In aspects of the invention, a maximum of 17 amino acids have been modified. In aspects of the invention, a maximum of 15 amino acids have been modified. In aspects of the invention, a maximum of 10 amino acids have been modified. In aspects of the invention, a maximum of 8 amino acids have been modified. In aspects of the invention, a maximum of 7 amino acids have been modified. In aspects of the invention, a maximum of 6 amino acids have been modified. In aspects of the invention, a maximum of 5 amino acids have been modified. In aspects of the invention, a maximum of 4 amino acids have been modified. In aspects of the invention, a maximum of 3 amino acids have been modified. In aspects of the invention, a maximum of 2 amino acids have been modified. In aspects of the invention 1 amino acid has been modified.

[062] In one aspect of the invention, the C-terminus of the derivative according to the invention may be terminated as an acid or amide. In one aspect, the C-terminus of the derivative of the invention is an amide. In another aspect, the C-terminus of the derivative of the invention is an acid.

[063] The present invention is especially suitable for making polypeptides or proteins comprising one or more non-proteogenic amino acids suitable for treating, for example, diabetes such as glucagon-like peptides and insulins.

[064] In one aspect, the polypeptide or protein to be reacted with the di-peptide is a glucagon-like peptide.

[065] The term "glucagon-like peptide", as used herein, means the glucagon family of polypeptides, exendins and analogues thereof. The glucagon family of polypeptides is encoded by the preproglucagon gene and comprises three small polypeptides with a high degree of homology, ie, glucagon (1-29), GLP-1 (1-37) and GLP-2 (1-33). Exendins are polypeptides expressed in lizards and like GLP-1, are insulinotropic. Examples of exendins are exendin-3 and exendin-4.

[066] The terms GLP-1, GLP-2, exendin-3 and exendin-4 are known to a person skilled in the art. For example, "GLP-1 compound" or "GLP-1 polypeptide" as used herein means human GLP-1(7-37), insulinotropic analogue thereof, and insulinotropic derivatives thereof. Non-limiting examples of GLP-1 analogs are GLP-1(7-36) amide, Arg34-GLP-1(7-37), Aib8Arg34-GLP-1(7-37), Gly8-GLP-1(7-37), Val8-GLP-1(7-36)-amide and Val8Asp22-GLP-1(7-37). Non-limiting examples of GLP-1 derivatives are desamino-His7, Arg26, Lys34(Nε-(Y-Glu(Nα-hexadecanoyl)))-GLP-1(7-37), desamino-His7, Arg26, Lys34(Nε-octanoyl)-GLP-1(7-37), Arg26'34, Lys38(Nε-(w-carboxypentadecanoyl ))-GLP-1(7-38), Arg26'34, Lys36(Nε-(Y—Glu(Nα-hexadecanoyl)))-GLP-1(7-36) and Arg34, Lys26(Nε-(Y-Glu(Nα-hexadecanoyl)))-GLP-1(7-37). In accordance with established practice in the art, GLP-1 naming begins at histidine residue which is referred to as #7, and subsequent amino acid residues are numbered accordingly, ending with glycine #37. Therefore, generally, any reference herein to an amino acid residue number or a sequence position number of GLP-1(7-37) is to the sequence starting with His at position 7 and ending with Gly at position 37. GLP-1 derivatives of the invention may be described by reference to i) the amino acid residue number in natural GLP-1(7-37) that corresponds to the amino acid residue that is changed (i.e., the corresponding position in natural GLP-1), and ii) the actual change.

[067] In one aspect, the glucagon-like peptide according to the invention is dipeptidyl aminopeptidase IV protected. In another aspect, the glucagon-like peptide according to the invention is dipeptidyl aminopeptidase IV protected.

[068] The term "protected dipeptidyl aminopeptidase IV" as used herein means a glucagon-like peptide, e.g., a GLP-1 analogue, which is more resistant to dipeptidyl aminopeptidase IV (DPP-IV) than the natural compound, e.g., GLP-1(7-37). Such protection can be obtained through, for example, mutations and/or derivatization of the natural compound. Resistance of a GLP-1 compound to degradation by dipeptidyl aminopeptidase IV is determined by the following degradation assay:

[069] Aliquots of the GLP-1 compound (5 nmols) are incubated at 37 °C with 1 μL of purified dipeptidyl aminopeptidase IV corresponding to an enzymatic activity of 5 mU for 10 to 180 minutes in 100 μL of 0.1 M triethylamine-HCl buffer, pH 7.4. Enzymatic reactions are terminated by the addition of 5 µL of 10% acetic trifluoroacid, and the polypeptide degradation products are separated and quantified using HPLC analysis. One method for performing this analysis is: The mixtures are loaded onto a 250 x 4.6 mm widepore Vydac C18 column (30 nm pores, 5 µm particles) and eluted at a flow rate of 1 ml/min with stepwise linear gradients of acetonitrile in 0.1% acetic trifluoroacid (0% acetonitrile for 3 min, 0 to 24% acetonitrile for 17 min, 24 to 48% acetonitrile for 1 min) according to Siegel et al., Regul. Pept. 1999;79:93-102 and Mentlein et al. eur. J. BioQuímica 1993;214: 829-35. Polypeptides and their degradation products can be monitored by their absorbance at 220 nm (peptide bonds) or 280 nm (aromatic amino acids), and are quantified by integrating their peak areas related to those of the standards. The rate of hydrolysis of a GLP-1 compound by di-peptidyl aminopeptidase IV is estimated at incubation times that result in less than 10% of the GLP-1 compound being hydrolyzed.

[070] The term "insulinotropic" as used herein referring to a glucagon-like peptide means the ability to stimulate insulin secretion in response to an increased plasma glucose level. Insulinotropic glucagon-like peptides are GLP-1 receptor agonists. The insulinotropic property of a compound can be determined by in vitro or in vivo assays known in the art. The following in vitro assay can be used to determine the insulinotropic nature of a compound such as a glucagon-like peptide. Preferably, insulinotropic compounds exhibit an EC50 value in the assay below less than 5 nM, even more preferably an EC50 value of less than 500 pM.

[071] Baby hamster kidney (BHK) cells expressing the cloned human GLP-1 receptor (BHK 467-12A) are cultured in DMEM media with the addition of 100 IU/mL penicillin, 100 μL/mL streptomycin, 10% fetal calf serum and 1 mg/mL Geneticin G-418 (Life Technologies). Plasma membranes are prepared by homogenization in buffer (10 mM Tris-HCl, 30 mM NaCl, and 1 mM dithiothreitol, pH 7.4, containing, in addition, 5 mg/mL leupeptin (Sigma), 5 mg/L pepstatin (Sigma), 100 mg/L bacitracin (Sigma), and 16 mg/L aprotinin (Calbiochem -Novabiochem, La Jolla, CA)). The homogenate is centrifuged on top of a layer of 41% w/v sucrose. The white band between the two layers is diluted in buffer and centrifuged. Plasma membranes are stored at -80°C until used.

[072] The functional receptor assay is performed by measuring cAMP as a response to stimulation by the insulinotropic polypeptide or insulinotropic compound. Incubations are performed in 96-well microtiter plates in a total volume of 140 mL and with the following final concentrations: 50 mM Tris-HCl, 1 mM EGTA, 1.5 mM MgSO4a, 1.7 mM ATP, 20 mM GTP, 2 mM 3-isobutyl-1-methylxanthine (IBMX), 0.01% w/v of Tween-20, pH 7.4. Compounds are dissolved and diluted in buffer. GTP is freshly prepared for each experiment: 2.5 μg of membrane is added to each well and the mixture is incubated for 90 min at room temperature in the dark with shaking. The reaction is stopped by the addition of 25 ml of 0.5 M HCl. cAMP formed is measured by a scintillation proximity assay (RPA 542, Amersham, UK). A dose-response curve is plotted for the compound and the EC50 value is calculated using GraphPad Prism software.

[073] The term "prodrug of an insulinotropic compound" as used herein means a chemically modified compound which following administration to the patient is converted into an insulinotropic compound. Such prodrugs are typically extended versions of the amino acid or esters of an insulinotropic compound.

[074] The term "exendin-4 compound" as used herein is defined as exendin-4(1-39), insulinotropic fragments thereof, insulinotropic analogues thereof, and insulinotropic derivatives thereof. Exendin-4 insulinotropic fragments are insulinotropic polypeptides for which the full sequence can be found in the exendin-4 sequence and where at least one terminal amino acid has been deleted. Examples of insulinotropic fragments of exendin-4(1-39) are exendin-4(1-38) and exendin-4(1-31). The insulinotropic property of a compound can be determined by in vivo or in vitro assays well known in the art. For example, the compound can be administered to an animal and monitor the insulin concentration over time. Insulinotropic analogues of exendin-4(1-39) refer to the respective molecules in which one or more of the amino acid residues have been exchanged with other amino acid residues and/or from which one or more amino acid residues have been deleted and/or from which one or more amino acid residues have been added with the guidance that said analogue is insulinotropic, i.e. a prodrug of an insulinotropic compound. An example of an insulinotropic analogue of exendin-4(1-39) is Ser2Asp3-exendin-4(1-39) in which the amino acid residues at position 2 and 3 have been replaced with serine and aspartic acid, respectively (this particular analogue also being known in the art as exendin-3). Insulinotropic derivatives of exendin-4(1-39) and analogues thereof are what those skilled in the art consider to be derivatives of these polypeptides, i.e., having at least one substituent which is not present in the original polypeptide molecule with the proviso that said derivative is insulinotropic or is a prodrug of an insulinotropic compound. Examples of substituents are amides, carbohydrates, alkyl groups, esters and lipophilic substituents. An example of an insulinotropic derivative of exendin-4(1-39) and analogue thereof is Tyr31-exendin-4(1-31)-amide.

[075] The term "stable exendin-4 compound" as used herein means a chemically modified exendin-4(1-39), i.e., an analogue or a derivative that exhibits an in vivo plasma elimination half-life of at least 10 hours in man, as determined by conventional methods.

[076] The term "dipeptidyl aminopeptidase IV-protected exendin-4 compound" as used herein means an exendin-4 compound that is more resistant to plasma dipeptidyl aminopeptidase IV (DPP-IV) peptidase than exendin-4, as determined by the assay described under the definition of dipeptidyl aminopeptidase IV-protected GLP-1 compound.

[077] GLP-1 analogues may be such that the naturally occurring Lys at position 34 of GLP-1(7-37) has been replaced with Arg.

[078] Also, derivatives of precursors or intermediates of insulinotropic polypeptides are covered by the invention.

[079] In one aspect of the invention, the glucagon-like peptide is insulintropic. In a further aspect, the insulintropic glucagon-like peptide is selected from the group consisting of GLP-1, GLP-2, exendin-4, exendin-3 and analogues and derivatives thereof.

[080] Conformational stability of protein-based drugs is important to maintain biological activity and to minimize irreversible loss of structure due to denaturation and fibrillation. Especially large insulinotropic polypeptides and proteins are unstable with respect to conformational change due to complicated refolding patterns. Also, insulinotropic polypeptides with a known history of fibrillation, such as GLP-1, are particularly sensitive for tertiary structure destabilization (ie, formation of a fused globular state).

[081] In one aspect, the constituent amino acids of a glucagon-like peptide according to the invention can be selected from the group of amino acids encoded by the genetic code and they can be natural amino acids that are not encoded by the genetic code, as well as synthetic amino acids. Natural amino acids that are not encoded by the genetic code are, for example, hydroxyproline, Y-carboxyglutamate, ornithine, phosphoserine, D-alanine and D-glutamine. Synthetic amino acids include amino acids manufactured by chemical synthesis, i.e., D-isomers of the amino acids encoded by the genetic code such as D-alanine and D-leucine, Aib (α-aminoisobutyric acid), Abu (α-am^b^π'ic acid), Tle (tert-butylglycine), β-alanine, 3-aminomethyl benzoic acid, anthranilic acid.

[082] In one aspect of the invention, the glucagon-like peptide to be reacted with the dipeptide according to the invention is a GLP-1 polypeptide. In a further aspect, the GLP-1 polypeptide is a GLP-1 peptide having a side chain mentioned in WO 2006/005667, WO 2005/027978, WO 2011/080103 or WO 2006/097537. In one aspect, the GLP-1 polypeptide is GLP-1(9-37); Arg34-GLP-1(9-37); Aib22,Arg34-GLP-1(9-37); Arg34, Pro37-GLP-1(9-37) or Aib22,27,30,35,Arg34,Pro37-GLP-1(9-37)amide which has a side chain mentioned in WO 2006/005667, WO 2005/027978, WO 2011/080103 or WO 2006/097537. In one aspect, the GLP-1 polypeptide is a GLP-1 peptide mentioned in WO 2011/080103 page 84, line 24 to page 95, line 2, or a GLP-1 analogue mentioned in WO 2006/097537 page 19, line 25 to page 22, line 4.

[083] In another aspect, the glucagon-like peptide to be reacted with the di-peptide according to the invention is a GLP-1 polypeptide which is selected from the group consisting of: Arg34-GLP-1(9-37); Aib22,Arg34-GLP-1(9-37); Arg34, Pro37-GLP-1(9-37); Aib,22,27,30,35,Arg34,Pro37-GLP-1(9-37)amide; Nε26-[2-(2-{2-[10-(4-Carboxyphenoxy)decanoylamino]ethoxy} ethoxy)acetyl], Nε37-[2- (2-{2-[10-(4-Carboxyphenoxy)decanoylamino]ethoxy}ethoxy)acetyl]-[Arg34,Lys37]GLP-1(9-37)-peptide; N^{2-[2-(2-{2-[2-(2-{(S)-4-Carboxy-4-[10-(4-Carboxyphenoxy)decanoylamino]-butyrylamino}ethoxy)ethoxy]acetylamino}ethoxy)ethoxy]acetyl}, Nε37-{2-[2-(2-{2-[2-(2-{(S)-4-carboxy-4-[10- (4-carboxyphenoxy)decanoylamino]butyrylamino}ethoxy)ethoxy]acetylamino}ethoxy)ethoxy]acetyl}-[Arg34,Lys37]GLP-1(9-37)-peptide; N^42-(2-{2-[2-(2-{2-[(S)-4-Carboxy-4-(15-carboxypentadecanoylamino)butyrylamino]ethoxy}ethoxy)acetylamino]ethoxy}ethoxy)acetyl], Nε37-[2-(2-{2-[2-(2-{2-[(S)-4-Carboxy-4-(15-carboxypentadecanoyl) amino)-butyrylamino]ethoxy}ethoxy)acetylamino]ethoxy}ethoxy)acetyl][Arg34,Lys37]GLP-1(9-37)-peptide amide; N£26-[2-(2-{2-[2-(2-{2-[(S)-4-Carboxy-4-(11-carboxyundecanoylamino)butyrylamino]ethoxy}ethoxy)acetylamino]ethoxy}ethoxy)acetyl], N£'57-[2-(2-{2-[2-(2-{2-[(S)-4-Carboxy-4-(11-carboxyundecanoylamino) )butyrylamino]ethoxy}ethoxy)acetylamino]ethoxy}ethoxy)acetyl]-[Arg34,Lys37]GLP-1(9-37)-peptide amide; N£26-[2-[2-(2-{2-[(S)-4-Carboxy-4-(13-carboxitridecanoylamino)butyrylamino]ethoxy}ethoxy)acetyl], N£'57-[2-[2-(2-{2-[(S)-4-Carboxy-4-(13-carboxitridecanoylamino)butyrylamino]ethoxy}ethoxy)acetyl] [Arg34 , Lys37]GLP-1(9-37)-peptide amide; Nε26 (17-carboxyheptadecanoyl)-[Arg34]GLP-1 -(9-37)-peptide; Nε26-(19-carboxinonedecanoyl)-[Arg34]GLP-1-(9-37)-peptide; Nε26-[2-(2-[2-(2-[2-(2-[4-(17-Carboxyheptadecanoylamino)-4(S)-carboxybutyrylamino]ethoxy)ethoxy]acetylamino)ethoxy]ethoxy)acetyl] [Arg34]GLP-1-(9-37)peptide; and Nε26-[2-(2-[2-(2-[2-(2-[4-(21-Carboxyuneicosanoylamino)-4(S)-carboxybutyrylamino]ethoxy)ethoxy]acetylamino)ethoxy]ethoxy)acetyl][Arg34]GLP-1-(9-37)peptide.

[084] In another aspect, the glucagon-like peptide to be reacted with the di-peptide according to the invention is a GLP-1 polypeptide which is selected from the group consisting of: Arg34-GLP-1(9-37); Aib22,Arg34-GLP-1(9-37); Arg34, Pro37-GLP-1(9-37); and Aib,22,27,30,35,Arg34,Pro37-GLP-1(9-37)amide

[085] In another aspect, the glucagon-like peptide to be reacted with the di-peptide according to the invention is a GLP-1 polypeptide which is selected from the group consisting of: Nε26-[2-(2-{2-[10-(4-Carboxyphenoxy)decanoylamino]ethoxy} ethoxy)acetyl], Nε37-[2- (2-{2-[10-(4-Carboxyphen) noxy)decanoylamino]ethoxy}ethoxy)acetyl]-[Arg34,Lys37]GLP-1(9-37)-peptide; N£76{2-[2-(2-{2-[2-(2-{(S)-4-Carboxy-4-[10-(4-carboxyphenoxy)decanoylamino]butyrylamino}ethoxy)ethoxy]acetylamino}ethoxy)ethoxy]acetyl}, N;;7-{2-[2-(2-{2-[2-(2-{(S)-4-carboxy-4-[10 -(4-carboxyphenoxy)decanoylamino]butyrylamino}ethoxy)ethoxy]acetylamino}ethoxy)ethoxy]acetyl}-[Arg34, Lys37]GLP-1(9-37)-peptide; N£26-[2-(2-{2-[2-(2-{2-[(S)-4-Carboxy-4-(15-carboxypentadecanoylamino)butyrylamino]ethoxy}ethoxy)acetylamino]ethoxy}ethoxy)acetyl], N£'57-[2-(2-{2-[2-(2-{2-[(S)-4-Carboxy-4-(15-carboxypenta) decanoylamino)butyrylamino]ethoxy}ethoxy)acetylamino]ethoxy}ethoxy)acetyl][Arg34,Lys37]GLP-1(9-37)-peptide amide; N£26-[2-(2-{2-[2-(2-{2-[(S)-4-Carboxy-4-(11-carboxyundecanoylamino)butyrylamino]ethoxy}ethoxy)acetylamino]ethoxy}ethoxy)acetyl], N£'57-[2-(2-{2-[2-(2-{2-[(S)-4-Carboxy-4-(11-carboxyundecanoylamino) )butyrylamino]ethoxy}ethoxy)acetylamino]ethoxy}thoxy)acetyl][Arg34,Lys37]GLP-1(9-37)-peptide amide; and N£26-[2-[2-(2-{2-[(S)-4-Carboxy-4-(13-carboxytridecanoylamino)butyrylamino]ethoxy}ethoxy)acetyl], N£'57-[2-[2-(2-{2-[(S)-4-Carboxy-4-(13-carboxitridecanoylamino)butyrylamino]ethoxy}ethoxy)acetyl][Arg3 4, Lys37]GLP-1(9-37)-peptide amide.

[086] In another aspect, the glucagon-like peptide to be reacted with the di-peptide according to the invention is a GLP-1 polypeptide which is selected from the group consisting of: N26 (17-carboxyheptadecanoyl)-[Arg34]GLP-1 -(9-37)-peptide; N-26-(19-carboxinonedecanoyl)-[Arg34]GLP-1-(9-37)-peptide; N-26-[2-(2-[2-(2-[2-(2-[4-(17-Carboxyheptadecanoylamino)-4(S)-carboxybutyrylamino]ethoxy)ethoxy]acetylamino)ethoxy]ethoxy)acetyl][Arg34]GLP-1-(9-37)peptide; and N-26-[2-(2-[2-(2-[2-(2-[4-(21-Carboxyuneicosanoylamino)-4(S)-carboxybutyrylamino]ethoxy)ethoxy]acetylamino)ethoxy]ethoxy)acetyl][Arg34]GLP-1-(9-37)peptide.

[087] In one aspect, a glucagon-like peptide comprising one or more non-proteogenic amino acids is obtained through the method of the invention. In another aspect, the glucagon-like peptide comprising one or more non-proteogenic amino acids obtained by the method of the invention is a GLP-1 peptide comprising one or more non-proteogenic amino acids. In a further aspect, the GLP-1 peptide comprising one or more non-proteogenic amino acids is a GLP-1 peptide comprising one or more non-proteogenic amino acids and having a side chain mentioned in WO 2006/005667, WO 2005/027978, WO 2011/080103 or WO 2006/097537. In one aspect, the GLP-1 peptide comprising one or more non-proteogenic amino acids is Aib8,Arg34-GLP-1(7-37); Aib8,22,Arg34-GLP-1(7-37); AIB8, ARG34, PRO37-GLP-1 (7-37) or AIB8,22,27,30,35, ARG34, PRO37- GLP-1 (7-37) Amide having a side chain mentioned in WO 2006/005667, WO 2005/027978, WO 2011/080103 or WO 2006/097537. In one aspect, the GLP-1 peptide comprising one or more non-proteogenic amino acids is a GLP-1 peptide mentioned in WO 2011/080103 in the section on page 84, line 24 linking to page 95, line 2, or a GLP-1 analogue mentioned in WO 2006/097537 in the section on page 19, line 25 linking to page 22, line 4.

[088] In one aspect, the GLP-1 peptide comprising one or more proteogenic amino acids is selected from the group consisting of: Aib8,Arg34-GLP-1(7-37); Aib8,22,Arg34-GLP-1(7-37); Arg34-GLP-1(7-37); Aib8,Arg34, Pro37-GLP-1(7-37); Aib8,22,27,30,35,Arg34,Pro37-GLP-1(7-37)amide; Nε26-[2-(2-{2-[10-(4-Carboxyphenoxy)decanoylamino]ethoxy} ethoxy)acetyl], Nε37-[2- (2-{2-[10-(4-Carboxyphenoxy)decanoylamino] ethoxy} ethoxy)acetyl]-[Aib8,Arg34,Lys37]GLP-1(7-37)peptide; N^{2-[2-(2-{2-[2-(2-{(S)-4-Carboxy-4-[10-(4-carboxyphenoxy)decanoylamino]butyrylamino}ethoxy)ethoxy]acetylamino}ethoxy)ethoxy]acetyl}, Nε3~-{2-[2-(2-{2-[2-(2-{(S)-4-carboxy-4-[10- (4-carboxyphenoxy)decanoylamino]butyrylamino}ethoxy)ethoxy]acetylamino}ethoxy)ethoxy]acetyl}-[Aib8,Arg34, Lys37]GLP-1(7-37)-peptide; N^42-(2-{2-[2-(2-{2-[(S)-4-Carboxy-4-(15-carboxypentadecanoylamino)butyrylamino]ethoxy}ethoxy)acetylamino]ethoxy}ethoxy)acetyl], Nε37-[2-(2-{2-[2-(2-{2-[(S)-4-Carboxy-4-(15-carboxypentadecanoyl) amino)butyrylamino]ethoxy}ethoxy)acetylamino]ethoxy}ethoxy)acetyl][Aib8,Arg34,Lys37]GLP-1(7-37)-peptide amide; N£26-[2-(2-{2-[2-(2-{2-[(S)-4-Carboxy-4-(11-carboxyundecanoylamino)butyrylamino]ethoxy}ethoxy)acetylamino]ethoxy}ethoxy)acetyl], N£'57-[2-(2-{2-[2-(2-{2-[(S)-4-Carboxy-4-(11-carboxy) ndecanoylamino)butyrylamino]ethoxy}ethoxy)acetylamino]ethoxy}ethoxy)acetyl][Aib8,Arg34,Lys37]GLP-1(7-37)-peptide amide; N£26-[2-[2-(2-{2-[(S)-4-Carboxy-4-(13-carboxitridecanoylamino)butyrylamino]ethoxy}ethoxy)acetyl], N£'57-[2-[2-(2-{2-[(S)-4-Carboxy-4-(13-carboxitridecanoylamino)butyrylamino]ethoxy}ethoxy)acetyl][A ib8, Arg34,Lys37]GLP-1(7-37)-peptide amide; N26 (17-carboxyheptadecane-1)-[Aib8,Arg34]GLP-1 -(7-37)-peptide; N-26-(19-carboxinonedecanoyl)-[Aib8,Arg34]GLP-1-(7-37)-peptide; N-26-[2-(2-[2-(2-[2-(2-[4-(17-Carboxyheptadecanoylamino)-4(S)-carboxybutyrylamino]ethoxy)ethoxy]acetylamino)ethoxy]ethoxy)acetyl][Aib8,Arg34]GLP-1-(7-37)peptide; and N-26-[2-(2-[2-(2-[2-(2-[4-(21-Carboxyuneicosanolamino)-4(S)-carboxybutyrylamino]ethoxy)ethoxy]acetylamino)ethoxy]ethoxy)acetyl][Aib8,Arg34]GLP-1-(7-37)peptide.

[089] In one aspect, the GLP-1 peptide comprising one or more proteogenic amino acids is selected from the group consisting of: Aib8,Arg34-GLP-1(7-37); Aib8,22,Arg34-GLP-1(7-37); Arg34-GLP-1(7-37); Aib8,Arg34, Pro37-GLP-1(7-37); and Aib8,22,27,30,35,Arg34,Pro37-GLP-1(7-37)amide.

[090] In one aspect, the GLP-1 peptide comprising one or more proteogenic amino acids is selected from the group consisting of: Nε26-[2-(2-{2-[10-(4-Carboxyphenoxy)decanoylamino]ethoxy}ethoxy)acetyl], Nε37-[2-(2-{2-[10-(4-Carboxyphenoxy)decanoylamino]ethoxy}ethoxy)ace thyla]-[Aib8,Arg34,Lys37]GLP-1(7-37) peptide; N£76{2-[2-(2-{2-[2-(2-{(S)-4-Carboxy-4-[10-(4-Carboxyphenoxy)decanoylamino]butyrylamino}ethoxy)ethoxy]acetylamino}ethoxy)ethoxy]acetyl}, N;;7-{2-[2-(2-{2-[2-(2-{(S)-4-carboxy-4- [10-(4-Carboxyphenoxy)decanoylamino]butyrylamino}ethoxy)ethoxy]acetylamino}ethoxy)ethoxy]acetyl}-[Aib8, Arg34,Lys37]GLP-1(7-37)-peptide; N£26-[2-(2-{2-[2-(2-{2-[(S)-4-Carboxy-4-(15-carboxypentadecanoylamino)butyrylamino]ethoxy}ethoxy)acetylamino]ethoxy}ethoxy)acetyl], N£'57-[2-(2-{2-[2-(2-{2-[(S)-4-Carboxy-4-(15-carboxy) entadecanoylamino)butyrylamino]ethoxy}ethoxy)acetylamino]ethoxy}ethoxy)acetyl][Aib8, Arg34,Lys37]GLP-1(7-37)-peptide amide; N£26-[2-(2-{2-[2-(2-{2-[(S)-4-Carboxy-4-(11-carboxyundecanoylamino)butyrylamino]ethoxy}ethoxy)acetylamino]ethoxy}ethoxy)acetyl], N£'57-[2-(2-{2-[2-(2-{2-[(S)-4-Carboxy-4-(11-carboxy) ndecanoylamino)butyrylamino]ethoxy}ethoxy)acetylamino]ethoxy}ethoxy)acetyl][Aib8,Arg34,Lys37]GLP-1(7-37)-peptide amide; and N£26-[2-[2-(2-{2-[(S)-4-Carboxy-4-(13-carboxytridecanoylamino)butyrylamino]ethoxy}ethoxy)acetyl], N£'57-[2-[2-(2-{2-[(S)-4-Carboxy-4-(13-carboxitridecanoylamino)butyrylamino]ethoxy}ethoxy)acetyl] [Aib8,Arg34, Lys37]GLP-1(7-37)-peptide amide.

[091] In one aspect, the GLP-1 peptide comprising one or more proteogenic amino acids is selected from the group consisting of: N26 (17-carboxy-heptadecanoyl|)—[Aib8,Arg34]GLP-1 -(7-37)-peptide; N-26-(19-carboxinonedecanoyl)-[Aib8,Arg34]GLP-1-(7-37)-peptide; N-26-[2-(2-[2-(2-[2-(2-[4-(17-Carboxyheptadecanoylamino)-4(S)-carboxybutyrylamino]ethoxy)ethoxy]acetylamino)ethoxy]ethoxy)acetyl][Aib8,Arg34]GLP-1-(7-37)peptide; and Ne26-[2-(2-[2-(2-[2-(2-[4-(21-Carboxyuneicosanoylamino)-4(S)-carboxybutyrylamino]ethoxy)ethoxy]acetylamino)ethoxy]ethoxy)acetyl][Aib8,Arg34]GLP-1-(7-37)peptide.

[092] The production of peptides and proteins is well known in the art. Peptides or proteins can, for example, be produced by classical peptide synthesis, e.g. solid phase peptide synthesis using t-Boc or Fmoc chemistry or other well established techniques, see, for example, Greene and Wuts, "Protector Groups in Organic Synthesis", John Wiley & Sons, 1999, "Organic Synthesis on solid phase", Florencio Zaragoza Dorwald, Wiley-VCH Verlag GmbH, D694 69 Weinheim, 2000, "Novabiochem Catalog", Merck Biosciences 2006/2007 and "Fmoc Solid Phase Peptide Synthesis", edited by W.C. Chan and P.D. White, Oxford University Press, 2000, ISBN 0-19-963724-5. The peptides or proteins can also be produced by a method comprising culturing a host cell containing a DNA sequence encoding the peptide or protein and capable of expressing the peptide or protein in a suitable nutrient medium under conditions that allow expression of the peptide or protein. For peptides or proteins comprising unnatural amino acid residues, the recombinant cell must be modified so that the unnatural amino acids are incorporated into the peptide or protein, for example through the use of tRNA mutants.

[093] The terms "about" or "approximately" as used herein mean in the reasonable vicinity of the indicated numerical value, such as plus or minus 10%, or for pH values plus or minus 0.2 or for temperature plus or minus 5 degrees Celsius.

[094] The following is a non-limiting list of embodiments according to the invention:

[095] A dipeptide of Chemical Formula 1: Chemical Formula 1 wherein R1 is H or an amino protecting group, and R2 is an amino protecting group; or R1 is a leaving alkyl group, and R2 is H or a leaving alkyl group; or R1 and R2 are together forming a ring; R3 is H, or a secondary ammonium cation, a tertiary ammonium cation, or a metal cation forming a salt with the carboxylate group; and R4 is absent or an acidic salt.

[096] The dipeptide of modality 1, in which the amino protecting group is selected from the group consisting of: Boc, Trt, Bpoc, Fmoc, Nsc, Cbz, Alloc, oNBS, pNBS, dNBS, ivDde and Nps.

[097] The dipeptide of embodiment 1 or 2, in which the removable alkyl group is selected from the group consisting of: Benzyl and tert-Butyl.

[098] The dipeptide of any one of Embodiments 1 to 3, wherein, where R1 and R2 are forming a ring together, the ring formed together is selected from the group consisting of: Fatalimide and 1,3,5-dioxazine.

[099] The dipeptide of any one of embodiments 1 to 4, wherein R1 is H or an amino protecting group selected from the group consisting of: Boc, Trt, Bpoc, Fmoc, Nsc, Cbz, Alloc, oNBS, pNBS, dNBS, ivDde and Nps, and R2 is an amino protecting group selected from the group consisting of: Boc, Trt, Bpoc, Fmoc, Nsc, Cbz , Alloc, oNBS, pNBS, dNBS, ivDde and Nps; or R1 is a removable alkyl group selected from the group consisting of: Benzyl and tert-Butyl, and R2 is H or a removable alkyl group selected from the group consisting of: Benzyl and tert-Butyl; or R1 and R2 are together forming a ring selected from the group consisting of: Fatalimide and 1,3,5-dioxazine; R3 is H, or a secondary ammonium cation, a tertiary ammonium cation, an alkali metal cation or an alkaline earth metal cation forming a salt with the carboxylate group; and R4 is absent or an acidic salt selected from the group consisting of: a TFA salt, an HCl salt, an HBr salt and a hydrogen sulfate salt.

[0100] The dipeptide of any one of embodiments 1 to 5, wherein R1 is H or an amino protecting group selected from the group consisting of: Boc, Trt, Bpoc, Fmoc, Nsc, Cbz, Alloc, oNBS, pNBS, dNBS, ivDde and Nps, and R2 is an amino protecting group selected from the group consisting of: Boc, Trt, Bpoc, Fmoc, Nsc, Cb z, Alloc, oNBS, pNBS, dNBS, ivDde and Nps.

[0101] The dipeptide of any one of embodiments 1 to 5, wherein R1 is H and R2 is an amino protecting group selected from the group consisting of: Boc, Trt, Bpoc, Fmoc, Nsc, Cbz, Alloc, oNBS, pNBS, dNBS, ivDde and Nps.

[0102] The dipeptide of any one of Embodiments 1 to 5, wherein R1 is H and R2 is Fmoc.

[0103] The dipeptide of any one of embodiments 1 to 5, wherein R1 is an amino protecting group selected from the group consisting of: Boc, Trt, Bpoc, Fmoc, Nsc, Cbz, Alloc, oNBS, pNBS, dNBS, ivDde and Nps, and R2 is an amino protecting group selected from the group consisting of: Boc, Trt, Bpoc, Fmoc, Nsc, Cbz, Alloc, oNBS, pNBS, dNBS, ivDde and Nps.

[0104] The dipeptide of any one of Embodiments 1 to 5, wherein R1 is a removable alkyl group selected from the group consisting of: Benzyl and tert-Butyl, and R2 is H or a removable alkyl group selected from the group consisting of: Benzyl and tert-Butyl.

[0105] The dipeptide of any one of embodiments 1 to 5, wherein R1 is a removable alkyl group selected from the group consisting of: Benzyl and tert-Butyl, and R2 is H.

[0106] The dipeptide of any one of embodiments 1 to 5, wherein R1 is a removable alkyl group selected from the group consisting of: Benzyl and tert-Butyl, and R2 is a removable alkyl group selected from the group consisting of: Benzyl and tert-Butyl.

[0107] The dipeptide of any one of Embodiments 1 to 12, wherein R3 is H.

[0108] The dipeptide of any of Embodiments 1 to 12, wherein R3 is a secondary ammonium cation forming a salt with the carboxylate group.

[0109] The dipeptide of any of embodiments 1 to 12, wherein R3 is a tertiary ammonium cation forming a salt with the carboxylate group.

[0110] The dipeptide of any one of Embodiments 1 to 12, wherein R3 is an alkali metal cation forming a salt with the carboxylate group.

[0111] The dipeptide of any one of Embodiments 1 to 12, wherein R3 is an alkaline earth metal cation forming a salt with the carboxylate group.

[0112] The dipeptide of any one of Embodiments 1 to 17, in which R4 is absent.

[0113] The dipeptide of any one of Embodiments 1 to 17, wherein R4 is an acidic salt selected from the group consisting of: a TFA salt, an HCl salt, an HBr salt, and a hydrogen sulfate salt.

[0114] The dipeptide according to any one of Embodiments 1 to 19, wherein R1 is H; R2 is Fmoc; R3 is H; and R4 is absent or an acidic salt such as TFA, HCl, HBr or HOAc.

[0115] The dipeptide according to any one of embodiments 1 to 3, which is Fmoc-His-Aib-OH of Chemical Formula 2 Chemical Formula 2 where His is histidine, Aib is the artificial amino acid 2-aminoisobutyric acid, Fmoc is the 9-fluorenylmethyloxycarbonyl protecting group, and R4 is absent or an acidic salt such as TFA, HCl, HBr, or HOAc.

[0116] The dipeptide according to any one of embodiments 1 to 3, which is the TFA salt of Fmoc-His-Aib-OH: Fmoc-His-Aib-OH,TFA where His is histidine, Aib is the artificial amino acid 2-aminoisobutyric acid, Fmoc is the 9-fluorenylmethyloxycarbonyl protecting group, and TFA is acetic trifluoroacid.

[0117] 23. The dipeptide according to any one of embodiments 1 to 22, which is activated by an activating agent such as a phosphonium-based coupling reagent such as (benzotriazol-1-yloxy)tripyrolidinophosphonium hexafluorophosphate (PyBOP).

[0118] 24. A method for producing a dipeptide according to any one of embodiments 1 to 23.

[0119] 25. A method for obtaining a polypeptide or protein comprising one or more non-proteogenic amino acids, in which the method comprises a step of reacting the dipeptide according to any one of embodiments 1 to 23 with a polypeptide or protein.

[0120] 26. A method for obtaining the polypeptide or protein according to embodiment 25, wherein said dipeptide is reacted with a polypeptide or protein in aqueous media.

[0121] 27. A method for obtaining a polypeptide or protein according to embodiment 25, comprising the step of mixing the dipeptide and the polypeptide or protein in aqueous media.

[0122] 28. A method for obtaining a polypeptide or protein according to any one of embodiments 25 to 27, in which R1 and/or R2 of said dipeptide are removed after completion of the reaction with a polypeptide or protein.

[0123] 29. A method for obtaining a polypeptide or protein according to any one of embodiments 25 to 28, in which R1 and/or R2 of said dipeptide are removed in a deprotection step under basic conditions.

[0124] 30. A method for obtaining a polypeptide or protein according to any one of embodiments 25 to 29, in which R1 and/or R2 of said dipeptide are removed in a deprotection step in which a piperidine is added to the reaction medium.

[0125] 31. A method for obtaining a polypeptide or protein according to any one of embodiments 25 to 30, in which R1 and/or R2 of said dipeptide are removed in situ in a chemical step after completion of the acylation reaction with a polypeptide or protein.

[0126] 32. A method for obtaining a polypeptide or protein according to any one of embodiments 25 to 31, wherein the polypeptide or protein is protected by the N-terminus Fmoc, comprising a step in which the polypeptide or protein protected by the N-terminus Fmoc is deprotected in situ.

[0127] 33. A method for obtaining a polypeptide or protein according to any one of embodiments 25 to 32, wherein the method comprises the steps: Activation of a dipeptide of Chemical Formula 1 or Chemical Formula 2 with a phosphonium-based coupling reagent. Reaction of said activated dipeptide with a polypeptide or protein Removal of the protecting group(s) in situ By which, the final polypeptide or protein is obtained.

[0128] 34. A method for obtaining a polypeptide or protein according to embodiment 33, wherein in step 2 said activated dipeptide is reacted with a polypeptide or protein in aqueous media.

[0129] 35. A method for obtaining a polypeptide or protein according to any one of embodiments 26 to 34, wherein said aqueous media comprise one or more water-soluble organic solvents selected from the group consisting of: DMF, NMP, DMAC, DMSO, acetonitrile, dioxane, butoxy-2-ethanol, a water-soluble acetal and a water-soluble alcohol.

[0130] 36. A method for obtaining a polypeptide or protein according to embodiment 35, wherein said one or more water-soluble organic solvents are NMP.

[0131] 37. A method for obtaining a polypeptide or protein according to any one of embodiments 26 to 36, in which the aqueous media, in which said activated dipeptide is reacted with a polypeptide or protein, comprises from 10 to 100% of water.

[0132] 38. A method for obtaining a polypeptide or protein according to any one of embodiments 26 to 36, wherein the aqueous medium, in which said activated dipeptide is reacted with a polypeptide or protein, comprises about 40% water.

[0133] 39. A method for obtaining a polypeptide or protein according to any one of embodiments 26 to 38, in which the pH of the aqueous media is between pH 7 and pH 14.

[0134] 40. A method for obtaining a polypeptide or protein according to any one of embodiments 26 to 38, wherein the pH of the aqueous media is between pH 8.7 and pH 9.4.

[0135] 41. A method for obtaining a polypeptide or protein according to any one of embodiments 26 to 38, wherein the pH of the aqueous media is about pH 9.1.

[0136] 42. A method for obtaining a polypeptide or protein according to any one of embodiments 26 to 38, wherein the pH of the aqueous media is about pH 9.3.

[0137] 43. A method for obtaining a polypeptide or protein according to any one of embodiments 26 to 38, wherein the aqueous media comprises a buffer.

[0138] 44. A method for obtaining a polypeptide or protein according to any one of embodiments 25 to 38, in which the polypeptide or protein comprising one or more non-proteogenic amino acids is obtained in solution.

[0139] 45. A method for obtaining a polypeptide or protein according to any one of embodiments 1 to 23, in which the polypeptide or protein reacted with said dipeptide is immobilized on a solid phase.

[0140] 46. The method for obtaining a polypeptide or protein according to any one of embodiments 1 to 23, wherein said dipeptide is reacted with the D-N-terminus of the polypeptide or protein.

[0141] 47. The method for obtaining a polypeptide or protein according to any one of embodiments 1 to 23, wherein the polypeptide or protein to be reacted with said dipeptide is a GLP-1 peptide. Examples List of Abbreviations ADO: 8-amino-3,6-dioxaoctanoic acid Aib: 2-aminoisobutyric acid Alloc: Allyloxycarbonyl Boc: tert-Butoxycarbonyl Bpoc: 2-(p-biphenylyl)-2-propyloxycarbonyl Cbz: Benzyloxycarbonyl DCM: Dichloromethane DIC: N,N'-Diisopropylcarbodiimide DIPEA: N,N-Diisopropylethyl amine DME: dimethyl ether dNBS: 2,4-Dinitrobenzenesulfonyl EtOH: Ethanol Fmoc: 9-fluorenylmethyloxycarbonyl HBr: hydrobromic acid HCl: Hydrochloric acid His: Histidine HOAc: Acetic acid HOBt: Hydroxybenzotriazole ivDde: 1-(4,4-Dimethyl-2,6-dioxocyclohexylidene)-3-methylbut Lys Lys: Lysine MeCN: Acetonitrile Mtt: 4-Methyltrityl NMP: N-Methyl-2-pyrrolidone Nps: o- or p-Nitrophenylsulfenyl Nsc: 2-(4-Nitrophenyl)sulfonylethoxycarbonyl oNBS: o-Nitrobenzenesulfonyl OtBu: tert-Butoxy pNBS: p-Nitrobenzenesulfonyl PyBOP: Hexa (Benzotriazol-1-yloxy)tripyrolidinophosphonium fluorophosphate TBME: tert-Butyl methyl ether TBTU: O-(Benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium tetrafluoroborate TEA: Trimethylamine TFA: acetic acid Trifluoroacid TIPS: Triisopropylsilane Trt: Triphenylmethyl

[0142] Example 1: 2-[(S)-2-(9H-Fluoren-9-ylmethoxycarbonylamino)-3-(1H-imidazol-4-yl)-propanoylamino]-2-methyl-propanoic acid trifluoroacate (alternative name: Fmoc-His-Aib-OH, TFA) Chemical Formula 3

[0143] Fmoc-His(Trt)-Aib-OH (1 mol eq., starting material) was suspended in DCM (1.5 mL/g) and TIPS (1.7 mol eq.) was added. Cooled (0 to 10oC) TFA (3 mL/g) was added and the mixture was stirred at room temperature until the reaction was complete (high performance liquid chromatography (HPLC) conversion). DME (1 mL/g starting material) and TBME (11 mL/g starting material) were added leading to an increase in temperature. The temperature was slowly allowed to return to room temperature (rt) resulting in precipitation of a white solid. The mixture was stirred for an additional 3 hours and filtered. The precipitate was washed twice with TBME (3 mL/g starting material) and dried overnight in vacuo affording the de-tritylated dipeptide as the TFA salt in 90% yield.

[0144] Stability studies in the freezer (<-15oC ±5oC), refrigerator (5oC ±3oC), and room temperature (20oC ±3oC) show more than 24 months of stability.

[0145] NMR data

[0146] Example 2: Nε26 [(S)-(22,40-dicarboxy-10,19,24-trioxo-3,6, 12,15-tetraoxa-9,18,23-triazatetracontan-1-oyl)] [Aib8, Arg34]GLP-1-(7-37) peptide (alternative name: Nε26 [2-(2-{2-[2) -(2-{2-[(S)-4-Carboxy-4-(17-carboxy-heptadecanoylamino)-butyrylamino]-ethoxy}-ethoxy)-acetylamino]-ethoxy}-ethoxy)-acetyl][Aib8, Arg34]GLP-1-(7-37) peptide). Step 1

[0147] In situ activation of Fmoc-His-Aib-OH,TFA dipeptide (Mixture I):

[0148] To a mixture of Fmoc-His-Aib-OH,TFA (4 mol eq.) and HOBt*H2O (4 mol eq.) was added NMP (4.7 mL/g of dipeptide) at room temperature. To the stirred solution, TEA was added until pH 8 while the temperature of the solution was maintained at room temperature using an ice bath. A solution of PyBOP (3.9 mol eq.) in NMP (2.4 mL/g of dipeptide) was added to the solution containing the dipeptide at room temperature. The pH of the reaction mixture was adjusted to pH 8 by using TEA. The mixture was stirred at room temperature for 20 min before addition to mixture II.

[0149] Preparation of the peptide (Nε26 [(S)-(22,40-dicarboxy-10, 19,24-trioxo-3,6,12,15-tetraoxa-9,18,23-triazatetracontan-1-oyl)] [Arg34]GLP-1-(9-37) peptide (alternative name: Nε26 [2-(2-{2 -[2-(2-{2-[(S)-4-Carboxy-4-(17-carboxy-heptadecanoylamino)-butyrylamino]-ethoxy}-ethoxy)-acetylamino]-ethoxy}-ethoxy)-acetyl][Arg34]GLP-1-(9-37) acylation peptide (Mixture II): Nε26 [(S)-(22,40-tip) rboxy-10,19,24-trioxo-3,6,12,15-tetraoxa-9,18,23-triazatetracontan-1-oyl)] [Arg34]GLP-1-(9-37) was suspended in 40% w/w H2O in NMP (37 g peptide/L solvent mixture). Into the cooled suspension TEA was added to pH 9.3. Step 2: Acylation of the Nε26 peptide [(S)-(22,40-dicarboxy-10,19,24-trioxo-3,6,12,15-tetraoxa-9,18,23-triazatetracontan-1-oyl)] [Arg34]GLP-1-(9-37) peptide (Mixture III):

[0150] Mixture I was added dropwise into mix II at room temperature. After addition, the pH was readjusted to pH 9.3 (pH meter) by TEA. The mixture was stirred until ideal conversion (measured by HPLC). Step 3: Removal of the protecting group (Fmoc)

[0151] In mixture III piperidine (20 mol eq./dipeptide) was added and the mixture was stirred for 40 min at rt.

[0152] Orbitrap m/z 1028.7 (4+) 1371.4 (3+)

[0153] Example 3: Preparation of Nε26,Nε37-bis[(S)-(22-carboxy-33-(4-Carboxyphenoxy)-10,19,24-trioxo-3,6,12,15-tetraoxa-9,18,23-triazatritriacontan-1-oyl)][Aib8,Arg34,Lys37]GLP-1-(7- 37) peptide (alternative name: Nε26-[2-[2-[2-[[2-[2- [2-[[(4S)-4-carboxy-4-[10-(4-Carboxyphenoxy)decanoylamino]butanoyl]amino]ethoxy]ethoxy]acetyl]amino]ethoxy]ethoxy]acetyl]-, Nε37-[2-[2-[2-[[2-[2 -[2-[[(4S)-4-carboxy-4-[10-(4-Carboxyphenoxy)decanoylamino]butanoyl]amino]ethoxy]ethoxy]acetyl]amino]ethoxy]ethoxy]acetyl]-[Aib8, Arg34, Lys37]-GLP-1-(7-37)-peptide) Step 1: Side chain acylation

[0154] [Arg34, Lys37]-GLP-1-(9-37)-peptide as an isoprecipitated pellet (15 g, peptide content approximately 13% w/w, purity ~93%) was suspended in water (50 mL) and NaOH (aq) (1 M; 1150 µL) was added to dissolve the peptide. The resulting solution (57 mL) was transferred to a 150 mL reaction chamber in a titrator setup. The pH of the solution was measured at 10.6. The pH was adjusted by the titrator to 11.3 with dilute NaOH (aq) (0.5 M, 0.67 mL) and the volume adjusted with water in 60 mL giving a final peptide concentration of approximately 33 mg/mL. Assaying the solution to a [Arg34,Lys37]-GLP-1-(9-37)-peptide standard curve gave a corrected peptide content of 1.71 g. Using 1.71 g of peptide gave a corrected solution concentration of 28.5 mg/mL. The activated side chain 2,5-dioxopyrrolidin-1-yloxy (S)-(22-carboxy-33-(4-Carboxyphenoxy)-10,19,24-trioxo-3,6,12,15-tetraoxa-9,18,23-triazatritriacontanate (alternative name: (4-[9-((S))-1-Carboxy-3-{2-[2-({2- [2-(2-hydroxy-5-oxo-pyrrolidin-1-yloxycarbonylmethoxy)-ethoxy]-ethylcarbamoyl}-methoxy)-ethoxy]-ethylcarbamoyl}-propylcarbamoyl)-nonyloxy]-benzoyl) as 83% active ester, 1.73 g 3.3 eq) was dissolved in NMP (4.8 mL) giving 5.20 mL of solution (0.63 eq/mL). Side chain NMP solution was added slowly from a syringe pump at a constant rate keeping the pH constant at 11.3 by the controlled addition of aq.(aq) (0.5 M) NaOH Titrator (0.5 M). 3.90 mL (2.4 eq) of side chain was added over 1 h and 10 minutes (~2 eq/h). Cylation is almost complete and addition was continued for a total of 2.8 eq of side chain (4.43 mL) During addition a total of (16.71 mL; 8.4 mmol) 0.5 N NaOH (aq) was added through the titrator. Step 2: Isoprecipitation

[0155] The reaction mixture was transferred with water into 4 x 50 mL centrifuge flasks (22 mL in each) and the pH in each was adjusted to 4.8 by the addition of conc. To give a white precipitate. EtOH (2.2 mL for approximately 10% v/v total) was added. The precipitate was centrifuged and used without further purification in the next step. Step 3: Dipeptide Binding

[0156] The isoprecipitate was suspended in NMP (48 mL; 50 mg of peptide/mL) and DIPEA (656 μL) was added. The pH of the resulting solution was measured at pH=9.6 in a 100 μL sample of the mixture diluted with 900 μL of water.

[0157] The water content of the slurry was measured at 1.4% by Karl Fischer titration. Water (9.12 mL) was added to give a water content of approximately 20%.

[0158] Fmoc-His-Aib-OH.TFA; (1058 mg, 3.5 eq) was activated with HOBt (248 mg; 3.5 eq), PyBOP (907 mg, 3.325 eq) and triethylamine (545 µL) in NMP for 15 minutes. The pH was 4 to 5 measured by a wet pH stick. The mixture was added into the peptide solution and the pH was adjusted with triethylamine to pH 9.3 (by measuring a sample of the reaction mixture (100 µL) added to water (900 µL). After 1 h, UPLC showed almost complete conversion to the desired product. Step 4: Fmoc deprotection

[0159] To the reaction mixture from the coupling step was added piperidine (3.35 mL, (5% v/v)) and the mixture was stirred for 25 minutes after which UPLC analysis showed complete conversion to the product. Water was added to give a 1:1 NMP-water solution and the pH was adjusted to 8.5 with acetic acid and the product purified by standard chromatography. Analysis:

[0160] RP-UPLC: BEH C18, 150*1mm@45oC and 0.1ml/min; 30 to 60% gradient 0.04% TFA in MeCN (eluent B) in 30 min then to 90% B, total run time 38 min. UV@215nm, 5Hz Synapt High Definition Mass Spectrometry (HDMS): positive mode ES-MS from m/z 200-2500 (1Hz). V(cap): 3kV; V(cone): 28V; Desolvation gas 250oC@750l/h; cone gas 50l/h@110oC

[0161] Rt = 15.18 min

[0162] Exact Mass: 4885.4477 Da; Found: M/4: 1222.35; M/3: 1629.45

[0163] Example 4: Preparation of N£26[(S)-(22-carboxy-33-(4-Carboxyphenoxy)-10,19,24-trioxo-3,6,12,15-tetraoxa-9,18,23-triazatritriacontan-1-oil)][Aib8,Arg34,Lys37]GLP-1-(7-37) peptide (name alternative:Nε26-[2-[2-[2-[[2-[2-[2- [[(4S)-4-carboxy-4-[10-(4-Carboxyphenoxy)decanoylamino]butanoyl]amino]ethoxy]ethoxy]acetyl]amino]ethoxy]ethoxy]acetyl]-[Aib8, Arg34, Lys37]-GLP-1-(7- 37 )-peptide):

[0164] The peptide was synthesized using solid-phase peptide synthesis:

[0165] To 1.04 g of Fmoc-Lys(Boc)-Wang-LL resin (eq. 0.24 mmol/g) was added in a gradual manner 4 mol eq. The standard Fmoc/OtBu protocol protected the amino acids either Ser-Ser pseudoproline or Fmoc-L-Lys(Mtt)-OH. Activation amino acid (4 mol eq.) in cartridge was reacted for 7 minutes with 4 mol eq. of DIC and 4 mol eq. of HOBt in NMP. The resulting peptide was transferred to a reaction vessel with resin and reacted for 30 min. DIPEA (4 mol eq.) was added and the reaction was continued for 30 min. The resin was flush washed with NMP and subsequently deprotected using 20% Piperidine (10ml, 20 min). The resin was again flush washed with NMP. MTT deprotection:

[0166] The resin was washed in DCM. 1,1,1,3,3,3-hexafluoro-2-propanol (10 ml over 10 min) was added and the resin drained. The deprotection procedure was repeated four times in total. The resin was washed with DCM, followed by NMP.

[0167] For a mixture of (S)-22-(tert-butoxycarbonyl)-33-(4-(tert-butoxycarbonyl)phenoxy)-10,19,24-trioxo-3,6,12,15-tetraoxa-9,18,23-triazatritriacontan-1-oic acid, HOBt (4 mol eq.) and DIPEA (4 mol eq.) in NMP (1 0 ml) was added, and TBTU (3.8 mol eq.) was added as a solid, and the mixture was stirred for 15 min. before being added to the resin. After 2 hours, the resin was drained and flush washed with NMP and DCM.

[0168] The peptidyl resin was swelled in NMP (10 mL) for 10 min at room temperature. The vessel was drained. 20 vol% piperidine in NMP (20 mL) was added to the resin. The mixture was swelled for 20 min at room temperature. The dipeptide Fmoc-L-His-Aib-OH.TFA (580 mg) and HOBt.H2O (153 mg) were placed in a 20 mL vial. NMP (4 mL) was added. To the mixture was added TEA (650 μL) until pH 8 (pH stick). To the reaction mixture was added a solution of PyBOP (500 mg) in NMP (4 mL). To the reaction mixture was again added TEA (200 μL) until pH 8 (pH stick). The mixture was stirred for 35 min at room temperature. The vessel was drained. 20 vol% piperidine in NMP (20 mL) was added back to the resin (double deprotection). The mixture was swelled for 20 min at room temperature and the resin was drained. The resin was flush washed with NMP (50ml), DCM (50ml) and 3 times with NMP (50ml). Finally, the resin was flush washed with DCM and drained. The peptide was cleaved from the resin by a mixture of TFA, H2O and TIPS (95%, 2.5%, 2.5%) for 3 h. The resulting cleaved peptide was precipitated from diethyl ether and isolated by filtration.

[0169] TOF MS ES+: m/z, found m/4 (1045.54), calculated m/4 (1045.5)

[0170] While certain aspects of the invention have been illustrated and described herein, many modifications, substitutions, changes and equivalents will occur to those skilled in the art. It is therefore to be understood that the appended claims are intended to cover all such modifications and changes as are within the true spirit of the invention.

Claims (24)

1. Dipeptide CHARACTERIZED by the fact that it has Chemical Formula 1: Chemical Formula 1 wherein R1 is H or an amino protecting group, and R2 is an amino protecting group; R3 is H; and R4 is absent or an acidic salt. 2. Dipeptide, according to claim 1, CHARACTERIZED by the fact that the amino protection group is selected from the group consisting of: Boc, Trt, Bpoc, Fmoc, Nsc, Cbz, Alloc, oNBS, pNBS, dNBS, ivDde and Nps. 3. Dipeptide, according to claim 1 or 2, CHARACTERIZED by the fact that R1 is H or an amino protection group selected from the group consisting of: Boc, Trt, Bpoc, Fmoc, Nsc, Cbz, Alloc, oNBS, pNBS, dNBS, ivDde and Nps, and R2 is an amino protection group selected from the group consisting of: Boc, Trt, Bpoc, F moc, Nsc, Cbz, Alloc, oNBS, pNBS, dNBS, ivDde and Nps; R3 is H; and R4 is absent or an acidic salt selected from the group consisting of: a TFA salt, an HCl salt, an HBr salt and a hydrogen sulfate salt. 4. Dipeptide, according to any one of claims 1 to 3, CHARACTERIZED by the fact that R1 is H, and R2 is an amino protection group; R3 is H; and R4 is absent or an acidic salt. 5. Dipeptide, according to any one of claims 1 to 4, CHARACTERIZED by the fact that R4 is absent. 6. Dipeptide, according to any one of claims 1 to 4, CHARACTERIZED by the fact that R4 is an acidic salt selected from the group consisting of: a TFA salt, an HCl salt, an HBr salt and a hydrogen sulfate salt. 7. Dipeptide, according to claim 1 or 2, CHARACTERIZED by the fact that it is Fmoc-His-Aib-OH of Chemical Formula 2 Chemical Formula 2 where His is histidine, Aib is the artificial amino acid 2-aminoisobutyric acid, Fmoc is the 9-fluorenylmethyloxycarbonyl protecting group, and R4 is absent or an acidic salt. 8. Dipeptide, according to claim 7, CHARACTERIZED by the fact that R4 is TFA, HCl, HBr or HOAc. 9. Dipeptide, according to claim 1 or 2, CHARACTERIZED by the fact that it is the TFA salt of Fmoc-His-Aib-OH: Fmoc-His-Aib-OH,TFA where His is histidine, Aib is the artificial amino acid 2-aminoisobutyric acid, Fmoc is the 9-fluorenylmethyloxycarbonyl protection group and TFA is trifluoroacetic acid. 10. Dipeptide according to any one of claims 1 to 9, CHARACTERIZED by the fact that it is activated by an activating agent such as a phosphonium-based coupling reagent such as (benzotriazol-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate (PyBOP). 11. Dipeptide, according to claim 10, CHARACTERIZED by the fact that the activating agent is a phosphonium-based coupling reagent such as (benzotriazol-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate (PyBOP). 12. Dipeptide, according to claim 11, CHARACTERIZED by the fact that said phosphonium-based coupling reagent is (benzotriazol-1yloxy)tripyrolidinophosphonium hexafluorophosphate (PyBOP). 13. Method for obtaining a final polypeptide or protein CHARACTERIZED by the fact that it comprises one or more non-proteogenic amino acids, in which the method comprises a reaction step of the dipeptide, as defined in any one of claims 1 to 9, with a first polypeptide or protein. 14. Method, according to claim 13, CHARACTERIZED by the fact that R1 and/or R2 of said dipeptide are removed in a deprotection step under basic conditions. 15. Method, according to claim 13 or 14, CHARACTERIZED by the fact that the pH of the aqueous media is between pH 8.7 and pH 9.4. 16. Method according to any one of claims 13 to 15, CHARACTERIZED by the fact that said dipeptide is reacted with the α-N-terminus of the polypeptide or protein. 17. Method according to any one of claims 13 to 16, characterized in that it comprises a step of activating said dipeptide by an activating agent. 18. Method, according to claim 17, CHARACTERIZED by the fact that the activated dipeptide is reacted with said first polypeptide or protein dissolved in an aqueous medium. 19. Method, according to claim 17 or 18, CHARACTERIZED by the fact that said activating agent is a phosphonium-based coupling reagent, such as tripyrrolidinophosphonium hexafluorophosphate (benzotriazol-1-yloxy) (PyBOP). 20. Method according to any one of claims 13 to 19, CHARACTERIZED by the fact that said activation comprises dissolving the dipeptide in an aprotic organic solvent or a mixture thereof, such as DMF, NMP, DMAC, DMSO, acetonitrile or dioxane, before said dipeptide is subjected to the reaction step. 21. Method, according to any one of claims 13 to 20, characterized by the fact that the amino protecting group is selected from the group consisting of: Boc, Trt, Bpoc, Fmoc, Nsc, Cbz, Alloc, oNBS, pNBS, dNBS, ivDde and Nps. 22. Method according to any one of claims 13 to 21, characterized by the fact that the dipeptide is dissolved in an aprotic organic solvent or a mixture thereof, such as DMF, NMP, DMAC, DMSO, acetonitrile or dioxane, before said dipeptide is subjected to the reaction step. 23. Method according to any one of claims 13 to 22, CHARACTERIZED by the fact that said first polypeptide is selected from the group consisting of: Nε26 (17-carboxyheptadecanoyl) - [Arg34] GLP-1- (9-37) peptide; Nε26-(19-carboxinonedecanoyl)-[Arg34]GLP-1-(9-37) peptide; Nε26-[2-(2-[2-(2-[2-(2-[4-(17-Carboxyheptadecanoamino)-4(S)-carboxybutyrylamino]ethoxy)ethoxy]acetylamino)ethoxy]ethoxy)acetyl][Arg34]GLP-1-(937) peptide; and Nε26-[2-(2-[2-(2-[2-(2-[4-(21-Carboxyuneicosanoylamino)-4(S)-carboxybutyrylamino]-ethoxy)ethoxy]acetylamino)ethoxy]ethoxy)acetyl][Arg34]GLP-1-(937) peptide. 24. Method according to any one of claims 13 to 23, CHARACTERIZED by the fact that said final polypeptide is selected from the group consisting of: Nε26 (17-carboxyheptadecanoyl) - [Aib8, Arg34] GLP-1- (7-37) -peptide; Nε26-(19-carboxinonedecanoyl)-[Aib8,Arg34]GLP-1-(7-37)-peptide; Nε26-[2-(2-[2-(2-[2-(2-[4-(17Carboxyheptadecanoylamino)-4(S)-carboxybutyrylamino]-ethoxy)ethoxy]acetylamino)ethoxy]ethoxy)acetyl][Aib8,Arg34]GLP-1-(7-37) peptide; and Nε26-[2-(2-[2-(2-[2-(2-[4-(21-Carboxyuneicosanoylamino)-4(S)-carboxybutyrylamino]-ethoxy)ethoxy]acetylamino)ethoxy]ethoxy)acetyl][Aib8,Arg34]GLP-1-(7-37) peptide.