Spectroscopic evidence for mobilization of amide position protons during CID of model peptide ions

Click on the DOI link below to access the article (may not be free).Infrared multiple photon dissociation (IRMPD) spectroscopy was used to study formation of b2+ from nicotinyl-glycine-glycine-methyl ester (NicGGOMe). IRMPD shows that NicGGOMe is protonated at the pyridine ring of the nicotinyl group, and more importantly, that b2+ from NicGGOMe is not protonated at the oxazolone ring, as would be expected if the species were generated on the conventional bn+/yn+ oxazolone pathway, but at the pyridine ring instead. IRMPD data support a hypothesis that formation of b2+ from NicGGOMe involves mobilization and transfer of an amide position proton during the fragmentation reaction.peer reviewe