Processing of an Anglerfish Somatostatin Precursor to a Hydroxylysine-Containing Somatostatin 28

• Published in: Proceedings of the National Academy of Sciences - PNAS 1985-01, Vol.82 (2), p.277-281
• Main Authors: Spiess, Joachim, Noe, Bryan D.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Amino acids; Amino Acids - analysis; Aminoacids, peptides. Hormones. Neuropeptides; Analytical, structural and metabolic biochemistry; Animals; Biochemistry; Biological and medical sciences; Chromatography, High Pressure Liquid; Collagens; DNA - analysis; Fishes; Fundamental and applied biological sciences. Psychology; Gels; growth hormone-release inhibiting hormone; Growth hormones; hormones; Hydroxylysine - analysis; Islets of Langerhans; Islets of Langerhans - analysis; Lophius americanus; Marine; molecular structure; peptides; Protein Precursors - metabolism; Proteins; Radioactive decay; Secretion; Sequence analysis; Sheep; Somatostatin - genetics; Somatostatin - metabolism; Somatostatin-28
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.82.2.277

A novel 28-residue somatostatin (SS) has been isolated from anglerfish pancreatic islets and characterized by complete Edman degradation, peptide mapping, and amino acid analysis. The primary structure of this anglerfish SS-28 (aSS-28) containing hydroxylysine (Hyl) was established to be H-Ser-Val-Asp-Ser-Thr-Asn-Asn-Leu-Pro-Pro-Arg-Glu-Arg-Lys-Ala-Gly-Cys-Lys-A sn -Phe-Tyr-Trp-Hyl-Gly-Phe-Thr-Ser-Cys-OH. This sequence (with the exception of hydroxylysine-23, which is replaced by lysine) is identical to the sequence of the COOH-terminal 28 residues of prepro-SS II predicted on the basis of cDNA analysis [Hobart, P., Crawford, R., Shen, L., Pictet, R. & Rutter, W. J. (1980) Nature (London) 288, 137-141]. This is the first instance in which hydroxylysine (to date characteristically observed in collagen or collagen-like structures) has been found in a potential regulatory peptide. Chromatographic characterization of peptides, radiolabeled in islet culture, revealed that aSS-28 contained 10-12% of the radioactivity incorporated into the 8000- to 1000-dalton SS-like polypeptides, whereas 88-90% of this radioactivity was detected in anglerfish SS-14. It appears probable that aSS-28 represents the predominant primary cleavage product derived from prepro-SS II by cleavage at the COOH-terminal side of a single arginine. Based on knowledge of the collagen biosynthesis, it is speculated that hydroxylation may take place as an early post-translational event.