a nonessential amino acid, CH(NH)S(COOH)
Origin of cystinecyst(o)- + -ine: so named from having been found first in urinary calculi
A white crystalline amino acid, C6H12N2O4S2, that is formed from the disulfide linkage of two cysteines during the folding of many proteins, especially keratin, and stabilizes the tertiary structure of the protein.
Origin of cystineFrom its discovery in bladder stones
(countable and uncountable, plural cystines)
From Ancient Greek κύστις (kustis, “bladder”), where it was found.