Peroxynitrite

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Ion

title: "Peroxynitrite" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["nitrogen-oxyanions", "atmospheric-chemistry", "toxins"] description: "Ion" topic_path: "science/chemistry" source: "https://en.wikipedia.org/wiki/Peroxynitrite" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Ion ::

| ImageFile = Peroxynitrite-ion-2D.png | ImageSize = 150px | ImageCaption = Chemical structure of the peroxynitrite anion | IUPACName = Oxido nitrite | OtherNames = | Section1 = {{Chembox Identifiers | CASNo = 19059-14-4 | ChemSpiderID = 94607 | Gmelin = 674445 | UNII_Ref = | UNII = UR67NH4U77 | PubChem = 104806 | KEGG = C16845 | ChEBI = 25941 | SMILES = N(=O)O[O-] | InChI=1S/HNO3/c2-1-4-3/h3H/p-1 | InChIKey=CMFNMSMUKZHDEY-UHFFFAOYSA-M | Section2 = {{Chembox Properties | N=1|O=3|Formula_Charge=- | Appearance = | Density = | MeltingPt = | BoilingPt = | Solubility = | Section3 = {{Chembox Hazards | MainHazards = | FlashPt = | AutoignitionPt =

::figure[src="https://upload.wikimedia.org/wikipedia/commons/c/cf/Reactions_of_peroxynitrite_leading_to_either_apoptotic_or_necrotic_cell_death.jpg" caption="Reactions of peroxynitrite leading to either apoptotic or necrotic cell death"] ::

Peroxynitrite (sometimes called peroxonitrite) 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: : H2O2 + → ONOO− + H2O Its presence is indicated by the absorbance at 302 nm (pH 12, ε302 = 1670 M−1 cm−1).

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 (carbonate radical and nitrogen dioxide) that are believed to cause peroxynitrite-related cellular damage.

Peroxynitrous acid

Main article: Peroxynitrous acid

Its conjugate acid peroxynitrous acid is highly reactive, although peroxynitrite is stable in basic solutions.

References

References

  1. Szabó, Csaba. (August 2007). "Peroxynitrite: biochemistry, pathophysiology and development of therapeutics". Nature Reviews Drug Discovery.
  2. (2004). "Tetramethylammonium Salts of Superoxide and Peroxynitrite".
  3. (2007). "Nitric oxide and peroxynitrite in health and disease". Physiological Reviews.
  4. (2007). "Peroxynitrite: Biochemistry, pathophysiology and development of therapeutics". Nature Reviews Drug Discovery.
  5. (1996). "Nitric oxide, superoxide, and peroxynitrite: The good, the bad, and ugly". American Journal of Physiology. Cell Physiology.
  6. Denicola, Ana. (1996-09-01). "Peroxynitrite Reaction with Carbon Dioxide/Bicarbonate: Kinetics and Influence on Peroxynitrite-Mediated Oxidations". Archives of Biochemistry and Biophysics.
  7. Holleman, A. F.; Wiberg, E. ''Inorganic Chemistry'' Academic Press: San Diego, 2001. {{ISBN. 0-12-352651-5.
  8. (1998). "The chemistry of peroxynitrite, a biological toxin". Química Nova.

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nitrogen-oxyanionsatmospheric-chemistrytoxins