cysteine
Last reviewed 01/2018
Cysteine is a sulphur-containing amino acids in which the R group in the general formula NH2-CHR-COOH is -CH2-SH. Two cysteine molecules in proximity can react at their sulphydryl groups to form a disulphide cross-bridge. This reaction is important as a determinant of the folding of peptide and polypeptide chains.