Peroxynitrite
Peroxynitrite is an ion with the formula ONOO−. It is a structural isomer of nitrate,. Peroxynitrite is a potent reactive nitrogen species and is highly cytotoxic.
Preparation
Peroxynitrite can be prepared by the reaction of superoxide with nitric oxide:It is prepared by the reaction of hydrogen peroxide with nitrite:
Its presence is indicated by the absorbance at 302 nm.
Reactions
Peroxynitrite is weakly basic with a pKa of ~6.8.It is reactive toward DNA and proteins.
ONOO− reacts nucleophilically with carbon dioxide. In vivo, the concentration of carbon dioxide is about 1 mM, and its reaction with ONOO− occurs quickly. Thus, under physiological conditions, the reaction of ONOO− with carbon dioxide to form nitrosoperoxycarbonate is by far the predominant pathway for ONOO−. homolyzes to form carbonate radical and nitrogen dioxide, again as a pair of caged radicals. Approximately 66% of the time, these two radicals recombine to form carbon dioxide and nitrate. The other 33% of the time, these two radicals escape the solvent cage and become free radicals. It is these radicals that are believed to cause peroxynitrite-related cellular damage.