ISOLATION AND CHARACTERIZATION OF INSULIN IN RUSSIAN STURGEON (ACIPENSER GULDENSTAEDTI)

Insulin was isolated from the pancreas of Chondrostean fish, the Russi an sturgeon, Acipenser guldenstaedti, by acid-ethanol extraction follo wed by ion-exchange and reverse-phase high-performance liquid chromato graphies. The amino acid sequence determined by automated Edman degrad ation is as follows: A-chain (21-amino-acid peptide), ro-Cys-Ser-Leu-T yr-Asp-Leu-Glu-Asn-Tyr-Cys-Asn-OH; and B-chain (31-amino-acid peptide) , n-His-Leu-Cys-Gly-Ser-His-Leu-Val-Glu-Ala-Leu-Tyr- ly-Glu-Arg-Gly-Ph e-Phe-Tyr-Thr-Pro-Asn-Lys-Val-OH. The sturgeon insulin appears to be i dentical with one of two forms of paddlefish insulin and differs from the other form by a single substitution in the A-chain, Asp15: His15. The amino acid sequence of sturgeon insulin is more similar to the ami no acid sequence of mammalian insulins than of other fish insulins. St urgeon insulin showed parallel but weaker displacement than porcine in sulin and pink salmon insulin in their respective radioimmunoassays an d was less potent than porcine insulin in displacing radiolabeled porc ine insulin bound to partially purified rat liver plasma membranes. (C ) Munksgaard 1998.