Identification of peptide oxidation by tandem mass spectrometry

Oxidative reactions play important roles in a variety of biochemical events ranging from normal metabolism to aging and disease processes. Proteins re present major targets for modification in these reactions, and identificati on of sites and structures of modifications may lead to mechanistic underst anding and approaches for prevention. In this Account, the utility of mass spectrometry and its advantages are described for the identification of oxi dative modifications to protein targets. A variety of examples are provided to illustrate how modifications are accurately identified and quantitated using modern methods of ionization coupled with HPLC and tandem mass spectr ometry.