PEROXYNITRITE - MEDIATOR OF THE TOXIC ACTION OF NITRIC-OXIDE

Peroxynitrite (oxoperoxonitrate(-1)), anion of peroxynitrous acid, is thought to mediate the toxic action of nitric oxide and superoxide ani on. Peroxynitrite is formed in a fast reaction between these species, reacts with all classes of biomolecules, is cytotoxic, and is thought to be involved in many pathological phenomena. Its main reactions invo lve one- and two-electron oxidation and nitration. Protein nitration i s often used as a footprint of peroxynitrite reactions in vivo. Nitrat ion of tyrosine and of tyrosyl residues in proteins may be an importan t mechanism of derangement of biochemical signal transduction by this compound. However, apparently beneficial effects of peroxynitrite have also been described, among them formation of nitric oxide and nitric oxide donors in reactions of peroxynitrite with thiols and alcohols.