Journal of the American Society for Mass Spectrometry

, Volume 15, Issue 4, pp 446–456

Fragmentation of deprotonated N-benzoylpeptides: Formation of deprotonated oxazolones


DOI: 10.1016/j.jasms.2003.11.018

Cite this article as:
Harrison, A.G. & Young, A.B. J Am Soc Mass Spectrom (2004) 15: 446. doi:10.1016/j.jasms.2003.11.018


The fragmentation reactions of deprotonated N-benzoyl peptides, specifically hippurylglycine, hippurylglyclyclycine, and hippurylphenylalanine (hippuryl = N-benzoylGly) have been studied using MS2 and MS3 experiments as well as deuterium labeling. A major fragment ion is observed at m/z 160 ([C9H6NO2]) which, upon collisional activation, mainly eliminates CO2 indicating that the two oxygen atoms have become bonded to the same carbon. This observation is rationalized in terms of formation of deprotonated 2-phenyl-5-oxazolone. Various pathways to the deprotonated oxazolone have been elucidated through MS3 experiments. Fragmentation of deprotonated N-acetylalanylalanine gives a relatively weak signal at m/z 112 which, upon collisional activation, fragments, in part, by loss of CO2 leading to the conclusion that the m/z 112 ion is deprotonated 2,4-dimethyl-5-oxazolone.

Download to read the full article text

Copyright information

© American Society for Mass Spectrometry 2004

Authors and Affiliations

  1. 1.Department of ChemistryUniversity of TorontoTorontoCanada