Pathways of Peptide Ion Fragmentation Induced by Vacuum Ultraviolet Light
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- Cui, W., Thompson, M.S. & Reilly, J.P. J Am Soc Mass Spectrom (2005) 16: 1384. doi:10.1016/j.jasms.2005.03.050
One Hundred Fifty-Seven nm photodissociation of singly protonated peptides generates unusual distributions of fragment ions. When the charge is localized at the C-terminus of the peptide, spectra are dominated by x-, v-, and w-type fragments. When it is sequestered at the N-terminus, a- and d-type ions are overwhelmingly abundant. Evidence is presented suggesting that the fragmentation occurs via photolytic radical cleavage of the peptide backbone at the bond between the α- and carbonyl-carbons followed by radical elimination to form the observed daughter ions.