Definition of "cysteine" [cysteine]

• An amino acid, C3H7O2NS, derived from cystine and found in most proteins. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Bacteria start self-cleaving in response to a molecule inside cells called InsP6, which in turn activates a process called cysteine protease."
• "All these contain an amino acid called cysteine, the basic building block of glutathione."
• "Nevertheless, whey is rich in glutamylcystine, a very stable and an easy to get inside the cell form of cysteine, which is a precursor of glutathione, and low glutathiione levels have been implicated in overtraining, cancer, Hepatitis, AIDS, Parkinson, Cystic Fibrosis and Sarcopenia lost of muscle mass."