Origin and Etymology of cysteine
International Scientific Vocabulary, from cystine + -ein
First Known Use: 1884
Medical Definition of cysteine
: a sulfur-containing amino acid C3H7NO2S occurring in many proteins and glutathione and readily oxidizable to cystine—abbreviation Cys
Seen and Heard
What made you want to look up cysteine? Please tell us where you read or heard it (including the quote, if possible).