Isolation and structures of glucagon and glucagon-like peptide from catfish pancreas.
Both glucagon and the structurally similar glucagon-like peptide proteolytically derived from preproglucagon were purified from the endocrine pancreas of the channel catfish (Ictalurus punctata). This study represents the first report of the isolation of glucagon-like peptide from any source. Peptide sequences of glucagon-like peptide from other species have only been deduced from the cDNA sequences for preproglucagon. The sequence of the 34-residue glucagon-like peptide was found to be HADGTYTSDVSSYLQDQAAKDFITWLKSGQPKPE. Catfish glucagon-like peptide shares sequence identity at 26 of 31 residues with the putative glucagon-like peptide from anglerfish preproglucagon II. The mass of catfish glucagon-like peptide was found by fast atom bombardment-mass spectrometry to be 3785, identical with the value predicted by sequence analysis. This suggests that no post-translational modification occurs beyond proteolytic processing. The sequence of catfish glucagon was determined to be HSEGTFSNDYSKYLETRRAQDFVQWLM(N,S). Catfish glucagon exhibits a high degree of immunologic similarity with porcine glucagon by radioimmunoassay, whereas catfish glucagon-like peptide does not.
D000262:Adenylyl Cyclases / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003429:Cross Reactions; D005399:Fishes; D005934:Glucagon / Q000276:immunology / Q000302:isolation & purification*; D004763:Glucagon-Like Peptides; D013058:Mass Spectrometry; D010179:Pancreas / Q000032:analysis*; D010455:Peptides / Q000276:immunology / Q000302:isolation & purification*
D010455:Peptides; D004763:Glucagon-Like Peptides; C015236:glucagon-like-immunoreactivity; D005934:Glucagon; D000262:Adenylyl Cyclases