title: The primary structure of ratfish insulin reveals an unusual mode of proinsulin processing.
abstract: The primary structure of insulin from the Holocephalan fish, Hydrolagus colliei (the ratfish), has been established by automated Edman degradation as: (Formula: see text). The presence of a COOH-terminal extension to the B-chain is consistent with the occurrence of a single base mutation in the region of the gene encoding one of the dibasic residue processing sites [Arg31(AGA)----Ile* (AUA)] with the result that the ratfish has utilised an alternative cleavage site within the C-peptide region of proinsulin.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D005075:Biological Evolution; D002851:Chromatography, High Pressure Liquid; D005399:Fishes / Q000378:metabolism*; D011384:Proinsulin / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D014101:Torpedo
chemical_list: D011384:Proinsulin