Gas-phase hydrogen/deuterium exchange as a molecular probe for the interaction of methanol and protonated peptides.
The gas-phase hydrogen/deuterium (HID) exchange kinetics of several protonated amino acids and dipeptides under a background pressure of CH3OD were determined in an external source Fourier transform mass spectrometer. H/D exchange reactions occur even when the gas-phase basicity of the compound is significantly larger (> 20 kcal/mol) than methanol. In addition; greater deuterium incorporation is observed for compounds that have multiple sites of similar basicities. A mechanism is proposed that involves a structurally specific intermediate with extensive interaction between the protonated compound and methanol.
Department of Chemistry, University of California, 95616, Davis, CA.
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Gard
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Green
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Bregar
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Lebrilla