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In‐beam electron impact mass spectrometry of N ‐carbobenzoxy derivatives of oligopeptides composed of leucine and isoleucine
Author(s) -
Ohashi Mamoru,
Tsujimoto Kazuo,
Tamura Shigeki,
Nakayama Noboru,
Okumura Yasuaki,
Sakurai Atsushi
Publication year - 1980
Publication title -
biomedical mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0306-042X
DOI - 10.1002/bms.1200070404
Subject(s) - tripeptide , chemistry , mass spectrum , mass spectrometry , electron ionization , leucine , ion , peptide , alkyl , spectral line , analytical chemistry (journal) , amino acid , organic chemistry , chromatography , physics , biochemistry , astronomy , ionization
The characteristics of the in‐beam electron impact mass spectra of 13 N ‐carbobenzoxyoligopeptides (up to pentapeptides) composed mainly of leucine and isoleucine, and their alkyl and N ‐hydroxysuccinimide esters are described. In the case of di‐ and tripeptide derivatives, each in‐beam electron impact spectrum exhibited an abundant [M + 1] + peak as well as amino‐acyl fragments. However, in the case of pentapeptides the in‐beam spectra measured under the routine conditions corresponded to the conventional electron impact spectra of the cyclopeptide derivatives formed by thermal cyclization in the mass spectrometer and few [M + 1] + ions of the original peptides were observed. From the studies on temperature dependent spectral change of in‐beam electron impact spectra it became clear that rapid heating of the sample over the temperature range 200–300 °C gave abundant [M + 1] + ions as well as fragment ions originating from the thermally intact peptide as the major peaks in the spectrum.