title: Isolation and structural characterisation of herring gull (Larus argentatus) pancreatic polypeptide.
abstract: Pancreatic polypeptide (PP) has been isolated from pancreatic extracts of the herring gull (Larus argentatus) using a radioimmunoassay employing an antiserum (PP 221), generated to the conserved C-terminal hexapeptide amide of mammalian PP. Gel permeation and reverse-phase HPLC fractionation of crude pancreatic extracts resolved a single molecular form of gull PP in each case. Purification of gull PP to homogeneity indicated that the mammalian PP antiserum employed was only 4% cross-reactive with this peptide. When radioimmunoassay data were corrected for this, the herring gull pancreas was found to contain 5 nmol PP/g wet wt. The molecular mass of gull PP was determined as 4237 +/- 2 Da by 252Cf plasma desorption mass spectroscopy (PDMS). Gas-phase sequencing established unequivocally the entire primary structure of a 36-amino-acid residue peptide as Gly-Pro-Val-Gln-Pro-Thr-Tyr-Pro-Gly-Asp-Asp-Ala-Pro-Val-Glu-Asp-Leu-Val- Arg-Phe - Try-Asn-Asp-Leu-Gln-Gln-Tyr-Leu-Asn-Val-Val-Thr-Arg-His-Arg-Tyr. The computed molecular mass of this peptide (4235.6 Da) was in close agreement with that derived by PDMS. The primary structure of herring gull PP differs from that of the chicken in four residues at positions 3 (Val/Ser), 18 (Val/IIe), 22 (Asn/Asp), and 23 (Asp/Asn). Avian PP thus appears to be a highly conserved regulatory peptide.
authors.affiliation: Comparative Neuroendocrinology Research Group, School of Clinical Medicine and Biology, Queen's University of Belfast, Northern Ireland.
authors.forename: C L
authors.initials: CL
authors.lastname: Barton
authors.forename: C
authors.initials: C
authors.lastname: Shaw
authors.forename: D W
authors.initials: DW
authors.lastname: Halton
authors.forename: L
authors.initials: L
authors.lastname: Thim
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001717:Birds; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010179:Pancreas / Q000737:chemistry*; D010191:Pancreatic Polypeptide / Q000737:chemistry / Q000302:isolation & purification*; D011863:Radioimmunoassay
chemical_list: D010191:Pancreatic Polypeptide