Cystine is formed from: (A) Arginine, (B) Histidine, (C) Cysteine, (D) Alanine
Answer is C. The difference in structure of cysteine and cystine. Two molecules of cysteine are joined together by S--S bond to form one molecule of cystine.Ref: M.N. Chatterjea - Textbook of Biochemistry, 8th edition, page no: 504