Charge promotion of low‐energy fragmentations of peptide ions

Abstract
We have examined the hypothesis that structural features which predispose to localization of charge at a strongly favored site are not conducive to the low‐energy fragmentation of peptide ions via a multiplicity of pathways. Consistent with this proposal, it is demonstrated that the formation of N‐ or C‐terminal pre‐charged derivatives is detrimenal to the formation of sequence‐specific product ions following low‐energy collisional activation. Protonation of pre‐charged derivatives (yielding doubly charged ions) restores favorable fragmentation properties; the effect is attributed to the fragmentation‐directing properties of the proton whih may occupy one of several sites. Similarly, a doubly protonated peptide which incorporates a C‐terminal arginine residue as a single strongly favored site of protonation exhibits favored low‐energy fragmentations attributable to locaton of he second proton at one of several sites remote from the C‐terminus.

This publication has 22 references indexed in Scilit: