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Negative ion fragmentations of deprotonated peptides: backbone cleavages directed through both Asp and Glu
Author(s) -
Brinkworth Craig S.,
Dua Suresh,
McAnoy Andrew M.,
Bowie John H.
Publication year - 2001
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.457
Subject(s) - chemistry , side chain , cleavage (geology) , deprotonation , stereochemistry , carboxylate , ion , peptide , mass spectrum , organic chemistry , biochemistry , geotechnical engineering , engineering , polymer , fracture (geology)
The collision‐induced spectra of [M − H] − ions of a variety of natural and synthetic amphibian peptides containing Asp and/or Glu exhibit characteristic γ backbone cleavage ions that identify the positions of these residues in the peptide. A theoretical study suggests that the Glu cleavage involves an S N i reaction of the carboxylate anion from the Glu α side chain to form a deprotonated cyclic lactone. The presence of either Asp or Glu or other residues that effect pronounced side‐chain cleavages (e.g. Ser or Thr) results in the normal α and β backbone cleavages being reduced in comparison to those cleavages which originate from side chains. Copyright © 2001 John Wiley & Sons, Ltd.