Human pancreatic icosapeptide: isolation, sequence, and immunocytochemical localization of the COOH-terminal fragment of the pancreatic polypeptide precursor.

AUTOR(ES)

Schwartz, T W

RESUMO

In dogs, the COOH-terminal part of the pancreatic polypeptide precursor gives rise to a stable icosapeptide product against which an antiserum has been raised. By immunohistochemistry, icosapeptide immunoreactivity was localized in human pancrease exclusively to cells that also stored pancreatic polypeptide. Analytical peptide chemistry demonstrated that a peptide corresponding to the canine icosapeptide could be extracted from the pancreatic polypeptide-rich duodenal part of the human pancreas. The human pancreatic icosapeptide was isolated by acid ethanol extraction, gel filtration, anion-exchange chromatography, and reverse-phase high-performance liquid chromatography. The COOH-terminal sequence of the human icosapeptide is very similar to that of the canine icosapeptide, whereas none of the first nine amino acid residues are identical. When the primary structure of peptides from three different species are compared, it is apparent that the pancreatic polypeptide part of the common precursor is a well-conserved sequence as compared to the icosapeptide part, although 8 out of 11 residues in the COOH-terminal sequence of the icosapeptide are identical in all three species.

Documentos Relacionados

• Are cysteine-rich and COOH-terminal domains of dystrophin critical for sarcolemmal localization?
• Noncovalent interaction of the NH2-terminal fragment of human somatotropin with the COOH-terminal fragment of human choriomammotropin to generate growth-promoting activity.
• Reassessment of the v-fms sequence: threonine phosphorylation of the COOH-terminal domain.
• Molecular cloning and amino acid sequence of the precursor form of bovine adrenodoxin: evidence for a previously unidentified COOH-terminal peptide.
• Cholecystokinin and its COOH-terminal octapeptide in the pig brain.