title: 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 detrimental 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 which 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 location of the second proton at one of several sites remote from the C-terminus.
authors: Center for Experimental Therapeutics, Baylor College of Medicine, Houston, TX 77030.
authors: O
authors: O
authors: Burlet
authors: R S
authors: RS
authors: Orkiszewski
authors: K D
authors: KD
authors: Ballard
authors: S J
authors: SJ
authors: Gaskell
mesh_terms: D013058:Mass Spectrometry / Q000379:methods; D010446:Peptide Fragments
chemical_list: D010446:Peptide Fragments