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Do amines react with protonated peptides in the gas phase via transacylation reactions to induce peptide bond cleavage? †
Author(s) -
O'Hair Richard A. J.,
Androutsopoulos N. K.,
Reid Gavin E.
Publication year - 2000
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 - 10.1002/1097-0231(20000930)14:18<1707::aid-rcm83>3.0.co;2-9
Subject(s) - chemistry , protonation , dimer , hydrogen bond , dissociation (chemistry) , pyridine , bond cleavage , triethylamine , amide , ion , molecule , photochemistry , stereochemistry , medicinal chemistry , organic chemistry , catalysis
The proposal that protonated peptides react with NH 3 in the gas phase via transacylation reactions (Tabet et al., Spectros. Int. J . 5 : 253 1987) has been investigated by studying the reactions of the fixed charge derivatives [RC(O)NMe 2 CH 2 CO 2 H] + (R=Me and Ph) with pyridine and triethylamine and the reactions of protonated glycine oligomers and leucine enkenphalin with butylamine. Under the near thermal conditions of the quadrupole ion trap, both the fixed charge derivatives as well as the protonated peptides react with the amines via either proton transfer or proton bound dimer formation. Collision induced dissociation of protonated peptides in the presence of butylamine yields b n and y n sequence ions as well as [b n + BuNH 2 ] + and [y n + BuNH 2 ] + ions. MS 3 experiments reveal that a major route to these [b n + BuNH 2 ] + and [y n + BuNH 2 ] + ions involves ion‐molecule reactions between the b n and y n sequence ions and butylamine. MS 4 experiments, carried out to determine the nature of the [b n + BuNH 2 ] + ions, reveal that they correspond to a mixture of hydrogen bonded (i.e. proton bound dimer) and covalent amide bond structures. Copyright © 2000 John Wiley & Sons, Ltd.