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：1977
卷号：74
期号：4
页码：1308-1309
DOI：10.1073/pnas.74.4.1308
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The 15N chemical shifts of eight aliphatic tripeptides have been measured at the natural-abundance level. For a given tripeptide, the resonances of the COOH-terminal and NH2-terminal amino acids can be identified by measurements at low or high pH. The shifts of the NH2-terminal amino acid nitrogens are essentially independent of the amino acids in the rest of the peptide. The shifts of the other nitrogens are characteristic of the amino acids themselves and of the immediately preceding amino acid toward the NH2 terminus. Non-terminal amide nitrogens have shifts of about 6 ppm upfield of COOH-terminal amide nitrogens at the isoelectric point of measurement. 15N chemical shifts appear to have considerable potential value for peptide sequencing.
