Dissociation of the N-Cα bond and competitive formation of the [zn−H]•+ and [cn+2H]+ product ions in radical peptide ions containing tyrosine and tryptophan: The influence of proton affinities on product formation
- Cite this article as:
- Siu, CK., Ke, Y., Orlova, G. et al. J Am Soc Mass Spectrom (2008) 19: 1799. doi:10.1016/j.jasms.2008.09.026
- 297 Downloads
Dissociations at the N-Cα bond of tryptophan and tyrosine residues are the prevalent pathways in the fragmentations of radical cations of tripeptides that contain such as residues. This process involves a proton transfer from the β-carbon of the tryptophan or tyrosine residue to the carbonyl oxygen of the amide group, followed by cleavage of the N-Cα bond, generating low-lying proton-bound dimers that dissociate to give each an ionic and a neutral product. Formation of the [zn−H]∢+ or [cn+2H]+ ion is a competition between the two incipient fragments for the proton in a dissociating proton-bound dimer.