标题：Human pancreatic icosapeptide: isolation, sequence, and immunocytochemical localization of the COOH-terminal fragment of the pancreatic polypeptide precursor
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1984
卷号：81
期号：3
页码：708-712
DOI：10.1073/pnas.81.3.708
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：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.
