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 represent major targets for modification in these reactions, and identification of sites and structures of modifications may lead to mechanistic understanding and approaches for prevention. In this Account, the utility of mass spectrometry and its advantages are described for the identification of oxidative 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 spectrometry.