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：1980
卷号：77
期号：11
页码：6827-6831
DOI：10.1073/pnas.77.11.6827
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The primary structure of the NH2-terminally extended somatostatins isolated from ovine hypothalamic extracts, one containing 28 residues and the other 25, has been determined. The structure of somatostatin-28 is Ser-Ala-Asn-Ser-Asn-Pro-Ala-Met-Ala-Pro-Arg-Glu-Arg-Lys-Ala-Gly-Cys-Lys-Asn-Phe-Phe-Trp-Lys-Thr-Phe-Thr-Ser-Cys-OH; the shorter one, somatostatin-25, has the same sequence as somatostatin-28 except that the first three NH2-terminal residues are deleted. The two peptides as isolated were found to be oxidized at the methionine residue to the methionine sulfoxide. Their structures were established by subjecting the native peptides to direct sequence analysis in a Beckman 890C sequencer and identifying the released phenylthiohydantoin derivatives by high-performance liquid chromatography. Their structures were confirmed by trypsin digestion and isolation of all the tryptic peptides, followed by amino acid analysis of the tryptic fragments. Moreover, some of the tryptic peptides were matched with their respective synthetic replicates on high-performance liquid chromatography.
