1. C00736 compound   Cysteine
                      2-Amino-3-mercaptopropionic acid

2. C00097 compound   L-Cysteine
                      L-2-Amino-3-mercaptopropionic acid

3. C00793 compound   D-Cysteine
                      D-Amino-3-mercaptopropionic acid

4. C00669 compound   gamma-Glutamylcysteine
                      L-gamma-Glutamylcysteine
                      5-L-Glutamyl-L-cysteine
                      gamma-L-Glutamyl-L-cysteine

5. C02668 compound   Cysteine thioether

6. C02743 compound   Protein cysteine

7. C02749 compound   S-Alkyl-L-cysteine

8. C03540 compound   S-Substituted L-cysteine

9. C03727 compound   S-Carboxymethyl-L-cysteine
                      Mucodyne
                      L-Carbocisteine

10. C03900 compound   S-(4-Bromophenyl)-L-cysteine

11. C04079 compound   N-Pantothenoylcysteine
                      D-Pantothenoyl-L-cysteine
                      N-((R)-Pantothenoyl)-L-cysteine

12. C04352 compound   (R)-4'-Phosphopantothenoyl-L-cysteine
                      N-[(R)-4'-Phosphopantothenoyl]-L-cysteine

13. C05526 compound   S-Glutathionyl-L-cysteine

14. C05824 compound   S-Sulfo-L-cysteine

15. C06751 compound   Prenyl-L-cysteine
                      S-Prenyl-L-cysteine

16. C03726 compound   S-Alkyl-L-cysteine S-oxide

17. C03800 compound   Protein S-methyl-L-cysteine

18. C04345 compound   S-Substituted N-acetyl-L-cysteine

19. C11490 compound   N-Acetyl-S-(N-methylcarbamoyl)cysteine
                      AMCC

20. C11605 compound   N-Acetyl 2,4-dinitrophenyl cysteine
                      N-Acetyl-S-(2,4-dinitrophenyl)-L-cysteine
                      NAc-DNP-Cys

21. C13015 compound   Cysteine ethyl ester hydrochloride
                      Ethyl L-cysteine hydrochloride
                      Daiace

22. C13279 compound   N-(2-Mercapto-2-methylpropionyl)-L-cysteine
                      Bucillamine

23. C04506 compound   Protein C-terminal S-farnesyl-L-cysteine

24. C08295 compound   S-[(E)-Prop-1-enyl]-L-cysteine S-oxide

25. C04748 compound   Protein C-terminal S-farnesyl-L-cysteine methyl ester