cysteine vs. cystine

cysteine vs. cystine: What's the difference?

Cysteine and cystine are both crystalline amino acids. Cystine, C₆H₁₂O₄N₂S₂, occurs in the keratin proteins in hair, wool, and horns, and yields cysteine, C₃H₇O₂NS, when reduced. The names come from cyst- ‘bladder or sac’ because these elements are also found in the bladder.

cysteine

[sis-tee-een, -in] / ˈsɪs tiˌin, -ɪn /

noun

Biochemistry.

a crystalline amino acid, C 3 H 7 O 2 NS, a component of nearly all proteins, obtained by the reduction of cystine. Cys; C

cystine

[sis-teen, -tin] / ˈsɪs tin, -tɪn /

noun

Biochemistry.

a crystalline amino acid, C 6 H 12 O 4 N 2 S 2 , occurring in most proteins, especially the keratins in hair, wool, and horn, and yielding cysteine on reduction.