Guinea pig proinsulin. Primary structure of the C-peptide isolated from pancreas.
The amino acid sequence of the proinsulin C-peptide isolated from guinea pig pancreas was determined and experimental data are presented. Digestion of the C-peptide with chymotrypsin provided two dodecapeptides, a tetrapeptide, and glutamine, which account for the intact chain. Reaction of the C-peptide with cyanogen bromide resulted in cleavage at the single methionine and provided two additional fragments. Digestion of the large peptides with papain provided a variety of small peptides and the complete sequence was assigned by identification of the fragments. Although guinea pig insulin differs markedly from mammalian insulins, guinea pig C-peptide has many features of primary structure in common with the C-peptides of other mammals. The conservation of specific residues in C-peptides indicates that these residues form essential elements in the three-dimensional structure of proinsulin.
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D006168:Guinea Pigs; D006801:Humans; D010179:Pancreas / Q000032:analysis*; D011384:Proinsulin; D013045:Species Specificity; D013552:Swine
D011384:Proinsulin