Primary structure of glucagon and a partial sequence of oxyntomodulin (glucagon-37) from the guinea pig.
Two glucagon-like peptides have been isolated from guinea pig pancreas and their primary structures determined. A 29-residue peptide is identical to the glucagons from all other mammals yet studied in the N-terminal region (residues 1-20) but the C-terminal region [Gln-Phe-Leu-Lys-Trp-Leu-Leu-Asn-Val] contains five substitutions. A 37-residue peptide probably represents guinea pig glucagon extended from the C-terminus by [Lys-Arg-Asn-Arg-Asn-Asn-Ile-Ala] and is analogous to human oxyntomodulin (glucagon-37). The structures suggest evolutionary pressure to conserve the N-terminal region of glucagon and the C-terminal region of oxyntomodulin. The biological activity of guinea pig glucagon has not yet been determined but it is speculated that changes in the C-terminal region of glucagon may have produced a molecule with reduced biological potency that is appropriate to the reduced potency of guinea pig insulin.
D000595:Amino Acid Sequence; D000818:Animals; D002852:Chromatography, Ion Exchange; D005768:Gastrointestinal Hormones / Q000302:isolation & purification*; D004763:Glucagon-Like Peptides / Q000302:isolation & purification*; D006168:Guinea Pigs; D053772:Oxyntomodulin; D010179:Pancreas / Q000032:analysis*; D011863:Radioimmunoassay
D005768:Gastrointestinal Hormones; D053772:Oxyntomodulin; D004763:Glucagon-Like Peptides