Protein tyrosine nitration--functional alteration or just a biomarker?

Protein 3-nitrotyrosine is a posttranslational modification found in many pathological conditions from acute to chronic diseases. Could 3-nitrotyrosine formation participate on the basis of these diseases or is it just a marker connected with the associated nitroxidative stress? In vitro and in vivo data, including proteomic research, show that protein tyrosine nitration is a selective process where only a small amount of proteins is found nitrated and one or a few tyrosine residues are modified in each. Accumulating data suggest a strong link between protein 3-nitrotyrosine and the mechanism involved in disease development. In this review, we analyze the factors determining protein 3-nitrotyrosine formation, the functional and biological outcome associated with protein tyrosine nitration, and the fate of the nitrated proteins.