The Chemistry of Peroxynitrite: Implications for Biological Activity

Sara Goldstein*, Gabor Merényi

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review

133 Scopus citations

Abstract

In biological systems, nitric oxide (NO) combines rapidly with superoxide (O2 -) to form peroxynitrite ion (ONOO-), a substance that has been implicated as a culprit in many diseases. Peroxynitrite ion is essentially stable, but its protonated form (ONOOH, pKa = 6.5 to 6.8) decomposes rapidly via homolysis of the O-O bond to form about 28% free NO2 and OH radicals. At physiological pH and in the presence of large amounts of bicarbonate, ONOO- reacts with CO2 to produce about 33% NO2 and carbonate ion radicals (CO3 -) in the bulk of the solution. The quantitative role of OH / CO3 - and NO2 radicals during the decomposition of peroxynitrite (ONOOH/ONOO-) under physiological conditions is described in detail. Specifically, the effect of the peroxynitrite dosage rate on the yield and distribution of the final products is demonstrated. By way of an example, the detailed mechanism of nitration of tyrosine, a vital aromatic amino acid, is delineated, showing the difference in the nitration yield between the addition of authentic peroxynitrite and its continuous generation by NO and O2 - radicals.

Original languageEnglish
Title of host publicationGlobins and Other Nitric Oxide-Reactive Proteins, Part A
PublisherAcademic Press Inc.
Pages49-61
Number of pages13
ISBN (Print)9780123742773
DOIs
StatePublished - 2008

Publication series

NameMethods in Enzymology
Volume436
ISSN (Print)0076-6879

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