title: Nitrating reactive nitric oxygen species transform acetaminophen to 3-nitroacetaminophen.
abstract: Nitrating reactive nitric oxygen species (RNOS) elicit many of the deleterious effects of the inflammatory response. Their high reactivity and short half-life make RNOS analysis difficult. Reaction of acetaminophen (APAP) with RNOS generated by various conditions was evaluated by HPLC. When [(14)C]APAP was incubated at pH 7.4, the same new product (3NAP) was produced by at least three separate pathways represented by the following conditions: myeloperoxidase oxidation of NO(2)(-), NO(2)Cl, and ONOO(-) or Sin-1. Diethylamine NONO and spermine NONO did not convert APAP to 3NAP. 3NAP was stable at pH 5, 7.4, or 9, and at pH 7.4 with ONOO(-), spermine NONO, Sin-1, or H(2)O(2). HOCl transformed 3NAP, which was prevented by APAP, ascorbic acid, taurine, or NO(2)(-). ONOO(-)-derived 3NAP was identified by (1)H NMR as 3-nitroacetaminophen or 3-nitro-N-acetyl-p-aminophenol, and the product mass was verified by EI/ESI mass spectrometry. Human polymorphonuclear neutrophils incubated with [(14)C]APAP and stimulated with beta-phorbol 12-myristate 13-acetate produced 3NAP in the presence of NO(2)(-). Neutrophil 3NAP formation was verified by mass spectrometry and was consistent with myeloperoxidase oxidation of NO(2)(-). Spermine NONO supported 3NAP formation by stimulated cells in the absence of NO(2)(-). Results demonstrate that 3NAP is a product of nitrating RNOS generated by at least three separate pathways and may be a biomarker for nitrating mediators of inflammation.
authors.affiliation: VA Medical Center, Division of Geriatric Medicine, and Department of Biochemistry, St. Louis University School of Medicine, St. Louis, Missouri 63125-4199, USA.
authors.forename: V M
authors.initials: VM
authors.lastname: Lakshmi
authors.forename: F F
authors.initials: FF
authors.lastname: Hsu
authors.forename: B B
authors.initials: BB
authors.lastname: Davis
authors.forename: T V
authors.initials: TV
authors.lastname: Zenser
mesh_terms: D000082:Acetaminophen / Q000378:metabolism*; D000700:Analgesics / Q000378:metabolism*; D001711:Biotransformation; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D016166:Free Radical Scavengers; D006801:Humans; D009504:Neutrophils / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D015538:Nitrosation; D009195:Peroxidase / Q000378:metabolism
chemical_list: D000700:Analgesics; D016166:Free Radical Scavengers; D009569:Nitric Oxide; D000082:Acetaminophen; D009195:Peroxidase