Mass Spectrometry Analysis for Nitration of Proteins

Abstract

Various proteomics and immunological methods including mass spectrometry combined with both liquid and 2-D PAGE, and immunodetection have been employed to identify and characterize nitrated proteins from pathological samples. Nitrosative modifications regulate cellular signal transduction and pathogenesis of inflammatory responses and neurodegenerative diseases. Nitric oxide generates reactive nitrosative species, such as peroxynitrite (ONOO) that may be involved in a number of diseases. ONOO can mediate protein tyrosine nitration which causes structural changes of affected proteins and leads to their inactivation. Protein tyrosine nitration is a biomarker of oxidative stress and also influences protein structure and function. Recent advances in mass spectrometry have made it possible to identify modified proteins and specific modified amino acid residues. This review focuses on the significance of protein tyrosine nitration and the progress achieved in analytical methods. Although mass spectrometry of nitrated peptides has become a powerful tool for the analysis of nitrated peptides, the low stoichiometry of protein tyrosine nitration clearly demands the use of affinity chromatography to enrich modified proteins (or peptides).