Insulin consists of a 21-amino-acid A chain and a 30-amino-acid B chain linked by two disul.de bridges. ooo0aaocodddaddde C peptide 31 GIn Arg Dipeptide linkage -COOH 1 Gly Asn 21 lle Cys NH2- Val Tyr Dipeptide(Arg lu Insulin linkage Phe A chain Glu g中e@8@w 00008e@0@80列0g66国ss586② GIn Thr s 30 10 Insulin Bchain 10 20