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Metastable fragmentation of somatostatin‐14 (SS‐14) and a series of SS‐14 analogs formed with liquid secondary ion mass spectrometry: Observation of fragment ions which involve unsymmetric disulfide bridge cleavage concomitant with peptide chain cleavage
Author(s) -
Craig A. Grey,
Rivier Jean E.
Publication year - 1992
Publication title -
organic mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0030-493X
DOI - 10.1002/oms.1210270503
Subject(s) - chemistry , ion , fragmentation (computing) , metastability , molecule , cleavage (geology) , mass spectrum , protonation , mass spectrometry , stereochemistry , disulfide bond , tandem mass spectrometry , crystallography , analytical chemistry (journal) , chromatography , organic chemistry , materials science , fracture (geology) , computer science , composite material , operating system , biochemistry
Somatostatin‐14 (SS‐14) and several SS‐14 analogs were analyzed using liquid secondary ion mass spectrometry (LSIMS). The observed isotope distributions showed low levels of [H 2 ‐SS‐14] (reduced SS‐14). The daughter‐ion spectra of the protonated molecule ions of SS‐14 and several SS‐14 analogs contained a number of metastable fragment ions. Two fragments in these spectra were assigned to cleavage of the peptide chain concomitant with unsymmetric cleavage of the disulfide bridge. Single alanine‐substituted analogs of SS‐14 were used to confirm these assignments, while single D isomer‐substituted analogs of SS‐14 were used to investigate the dependence of the cleavages on conformation.