Primary structures of somatostatins from the islet organ of the hagfish suggest an anomalous pathway of posttranslational processing of prosomatostatin-1.

摘要: The cyclostomes represent the first class of vertebrate in evolution to develop an endocrine pancreas. Two peptides with somatostatin-like immunoreactivity were isolated from islet organ one such cyclostome, Atlantic hagfish (Myxine glutinosa). primary structure more abundant peptide was established as: Ala-Val-Glu-Arg-Pro5-Arg-Gln-Asp-Gly-Gln10-Val-His-Glu-Pro- Pro15-Gly-Arg-Glu-Arg-Lys20-Ala-Gly-Cys-Lys-Asn25-Phe- Phe-Trp-Lys-Thr30-Phe-Thr-Ser-Cys. second peptide, comprising 27% total extract, identical mammalian somatostatin-14. pathway posttranslational processing prosomatostatin differs markedly higher vertebrates. In pancreas, is cleaved at site single arginyl residue (corresponding position 6 somatostatin-34) and arginine-lysine positions 19 20 peptide) generate somatostatin-14 somatostatin-28(1-12)-peptide. islet, Arg6 not used as a cleavage Arg19-Lys20 represents only minor processing. data provide further evidence strong evolutionary pressure conserve complete amino acid sequence