The chemical L-Cysteine has a designated molecular formula of C3H7NO2S and a molecular weight of 121.154 g/mol. Synonyms may include: Cysteine, AI3-26559, L-Alanine, 3-mercapto-, alpha-Amino-beta-mercaptopropanoic acid, L-, (R)-2-Amino-3-mercaptopropanoic acid, 2-Amino-3-mercaptopropanoic acid, (R)-, alpha-Amino-beta-mercaptopropionic acid, L-, (R)-2-Amino-3-mercaptopropionic acid, 2-Amino-3-mercaptopropionic acid (ChemID).