Quantitative proteome mapping of nitrotyrosines

An essential first step in the understanding disease and environmental perturbations is the early and quantitative detection of the increased levels of the inflammatory marker nitrotyrosine, as compared with its endogenous levels within the tissue or cellular proteome. Thus, methods that successfully address a proteome-wide quantitation of nitrotyrosine and related oxidative modifications can provide early biomarkers of risk and progression of disease, as well as effective strategies for therapy. Multidimensional separations LC coupled with tandem mass spectrometry (LC-MS/MS) has, in recent years, significantly expanded our knowledge of human (and mammalian model system) proteomes, including some nascent work in identification of posttranslational modifications. This chapter discusses the application of LC-MS/MS for quantitation and identification of nitrotyrosine-modified proteins within the context of complex protein mixtures presented in mammalian proteomes.