Process for the stabilization of proteins in an aqueous solution comprising cysteine in a concentration between 150 and 220mM

1. A process for the storage of a protein in an aqueous solution, comprising adding an amount of cysteine to make the concentration of cysteine between 150 and 220 mM thereby delaying decrease in the effective concentration of the protein by reducing chemical modification of SH groups on the protein during storage.

2. The process as claimed in claim 1 , wherein the effective concentration does not decrease by more than about 3%.

3. The process as claimed in claim 1 , wherein the protein is a heterologous protein produced in an organism.

4. The process as claimed in claim 3 , wherein the organism is a microorganism.

5. The process as claimed in claim 4 , wherein the microorganism is a bacterium.

6. The process as claimed in 5 , wherein the bacterium is Escherichia coli.

7. The process as claimed in claim 4 , wherein the microorganism is a yeast.

8. The process as claimed in claim 7 , wherein the yeast is Saccharomyces cerevisiae.

9. The process as claimed in claim 7 , wherein the yeast is Pichia pastoris.

10. The process as claimed in claim 1 , wherein the protein is a heterologous protein and is produced in an insect cell.

11. The process as claimed in claim 3 or claim 10 , wherein the protein is encoded by an expression vector comprising a nucleic acid encoding the protein.

12. The process as claimed in claim 1 , wherein the protein is present in dissolved form.

13. The process as claimed in claim 1 , wherein the protein is present in suspension.

14. The process as claimed in claim 1 , wherein the storage of the protein takes place at about 0° C. to about 50° C.

15. The process as claimed in claim 14 , wherein the storage of the protein takes place at about 5° C. to about 30° C.

16. The process as claimed in claim 14 , wherein the storage of the protein takes place at about 5° C.

17. The process as claimed in claim 1 , wherein the protein is insulin, an insulin derivative, or a precursor thereof.

18. A process for the preparation and storage of a heterologous protein, comprising the expression of the heterologous protein or a precursor thereof in a transformed microorganism, optional disruption of the microorganism and/or isolation of the heterologous protein or its precursor from the culture medium, and the subsequent storage of the heterologous protein according to the process of claim 1 .

19. The process of claim 18 , wherein the protein has been denatured, said process comprising renaturation of the heterologous protein or its precursor and the purification of the heterologous protein, including optional removal of a leader sequence or other sequences that may be present in the precursor of the heterologous protein.

20. The process as claimed in claim 18 , wherein the heterologous protein is animal insulin.

21. The process as claimed in claim 20 , wherein the animal insulin is human insulin.

22. A process for the storage of a protein in an aqueous solution, comprising adding an amount of cysteine to make the concentration of cysteine between 150 and 220 mM thereby delaying decrease in the effective concentration of the protein by reducing chemical modification of SH groups on the protein during a period of greater than 24 hours.

23. The process as claimed in claim 22 , wherein the temporal decrease in the effective concentration of the protein is delayed for a storage period of 48 hours or more.

24. The process as claimed in claim 22 , wherein the temporal decrease in the effective concentration of the protein is delayed for a storage period of 1 week or more.

25. The process as claimed in claim 22 , wherein the temporal decrease in the effective concentration of the protein is delayed for a storage period of 2 weeks or more.

26. The process as claimed in claim 22 , wherein the temporal decrease in the effective concentration of the protein is delayed for a storage period of 4 weeks or more.

27. The process as claimed in claim 22 , wherein the temporal decrease in the effective concentration of the protein is delayed for a period of 8 weeks or more.

28. The process as claimed in claim 22 , wherein the temporal decrease in the effective concentration of the protein is delayed for a period of from greater than 24 hours to 2 months.

29. The process as claimed in claim 22 , wherein the protein is a heterologous protein produced in an organism.

30. The process as claimed in claim 29 , wherein the organism is a microorganism.

31. The process as claimed in claim 30 , wherein the microorganism is a bacterium.

32. The process as claimed in claim 31 , wherein the bacterium is Escherichia coli.

33. The process as claimed in claim 30 , wherein the microorganism is a yeast.

34. The process as claimed in claim 33 , wherein the yeast is Saccharomyces cerevisiae.

35. The process as claimed in claim 33 , wherein the yeast is Pichia Pastoris.

36. The process as claimed in claim 22 , wherein the protein is a heterologous protein and is produced in an insect cell.

37. The process as claimed in claim 29 or claim 36 . wherein the protein is encoded by an expression vector comprising a nucleic acid encoding the protein.

38. The process as claimed in claim 22 , wherein the protein is present in dissolved form.

39. The process as claimed in claim 22 , wherein the protein is present in suspension.

40. The process as claimed in claim 22 , wherein the storage of the protein takes place at about 0° C. to about 50° C.

41. The process as claimed in claim 40 , wherein the storage of the protein takes place at about 5° C. to about 30° C.

42. The process as claimed in claim 40 , wherein the storage of the protein takes place at about 5° C.

43. The process as claimed in claim 22 , wherein the protein stored is insulin, an insulin derivative, or a precursor thereof.

44. A process for the preparation and storage of a heterologous protein, comprising the expression of the heterologous protein or its precursor in a transformed microorganism, optional disruption of the microorganism and/or isolation of the heterologous protein or its precursor from the culture medium, and the subsequent storage of the heterologous protein according to the process of claim 22 .

45. The process of claim 44 , wherein the protein has been denatured, said process comprising renaturation of the heterologous protein or its precursor and the purification of the heterologous protein, including optional removal of a leader sequence or other sequences that may be present in the precursor of the heterologous protein.

46. The process as claimed in claim 44 , wherein the heterologous protein is animal insulin.

47. The process as claimed in claim 44 , wherein the animal insulin is human insulin.