Protonated peptides containing the basic amino acids histidine, lysine or arginine are reacted at low beam energies in a tandem mass spectrometer with dimethyl- and trimethylamine. Proton transfer reactions are observed at clearly defined thresholds on the ion beam energy scale that are consistent with predicted endothermicites. At similar beam energies abundant sequence fragment ions are also observed that appear to result from alternate dissociation channels for a long-lived collision complex formed in the proton transfer reaction. The observed endothermicity and the selectivity for cleavages in which the charge is retained on basic residues are consistent with protonation of the molecular ion at those residues. Fragmentation induced by reactions with basic amines is referred to as reaction-induced dissociation to distinguish this process from collision-induced dissociations with inert gases.
|Original language||English (US)|
|Number of pages||14|
|Journal||International Journal of Mass Spectrometry and Ion Processes|
|State||Published - Dec 16 1991|
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