DUCK INSULIN: ISOLATION, CRYSTALLIZATION AND AMINO ACID SEQUENCE

Duck insulin was isolated and crystallized, and its amino acid sequence was elucidated. A comparison with chicken insulin, the only avian insulin so far sequenced, shows three differences. In the A-chain, duck insulin has glutamic acid at position 8 and proline at position 10, where chicken insulin exhibits histidine and threonine, respectively. In the B-chain, the only difference in sequences is located at position 30, where duck insulin has a threonine residue while chicken insulin has an alanine residue.