>4f51_A: Insulin A chain GIVEQCCTSICSLYQLENYCN >4f51_B: Insulin B chain FVNQHLCGSHLVEALYLVCGERGFFYTPKT >4f51_C: Insulin A chain GIVEQCCTSICSLYQLENYCN >4f51_D: Insulin B chain FVNQHLCGSHLVEALYLVCGERGFFYTPKT