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Updated: Aug 17, 2026

Determination of the Gas-phase Acidities of Oligopeptides
Published on: June 24, 2013
Pathways of peptide ion fragmentation induced by vacuum ultraviolet light
Weidong Cui1, Matthew S Thompson, James P Reilly
1Department of Chemistry, Indiana University, Bloomington, Indiana 47505-4001, USA.
Abstract:
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 alpha- and carbonyl-carbons followed by radical elimination to form the observed daughter ions.
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