Vasoactive intestinal polypeptide (VIP) was purified from extracts of the stomachs of the rainbow trout, Oncorhynchus mykiss, and bowfin, Amia calva. The primary structure of VIP from both species was the same: His-Ser-Asp-Ala-IIe-Phe-Thr-Asp-Tyr10-Ser-Arg-Phe-Arg-Lys-Gln-Met-Ala-Val-Lys20-Lys-Tyr-Leu-Asn-Ser-Val-Leu-Thr. This amino acid sequence shows only one amino acid substitution (Val5 → Ile) compared with the common sequence of VIP from the chicken, alligator, and European green frog. The structure identity of VIP from the trout and bowfin is consistent with the close phylogenetic relationship between the Salmoniformes and the Amiiformes and the data indicate that pressure to conserve the complete primary structure of VIP during vertebrate evolution has been very strong.
ASJC Scopus subject areas
- Animal Science and Zoology