title: Exchange of (18)O in the reaction of peroxynitrite with CO(2).
abstract: We have observed an exchange of (18)O in the reactions of CO(2) with peroxynitrite using membrane-inlet mass spectrometry and HPLC negative electrospray ionization mass spectrometry. The exchange appeared on addition of peroxynitrite to a solution containing (18)O-labeled CO(2) in equilibrium with bicarbonate. It was observed as a temporarily enhanced rate of depletion of (18)O from CO(2), a rate that was greater than the rate of (18)O depletion caused by the hydration/dehydration cycle of CO(2). In addition, we detected the appearance of mass peaks attributed to (18)O in product NO(3)(-). As a further measure of the (18)O exchange, there was a redistribution of (18)O such that the ratio of doubly to singly labeled CO(2) could not be described by the binomial expansion. This is not due to the hydration/dehydration cycle of CO(2) but most likely to recycling of CO(2) in the reaction with peroxynitrite. This (18)O exchange associated with the reactions of CO(2) and peroxynitrite may open a new methodology for studying this significant process.
authors.affiliation: Department of Pharmacology, Department of Biochemistry, University of Florida College of Medicine, Gainesville, FL 32610-0267, USA.
authors.forename: Chingkuang
authors.initials: C
authors.lastname: Tu
authors.forename: Patrick
authors.initials: P
authors.lastname: Quint
authors.forename: David N
authors.initials: DN
authors.lastname: Silverman
mesh_terms: D002245:Carbon Dioxide / Q000737:chemistry* / Q000378:metabolism; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry* / Q000378:metabolism; D010103:Oxygen Isotopes; D030421:Peroxynitrous Acid / Q000737:chemistry* / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D010103:Oxygen Isotopes; D002245:Carbon Dioxide; D030421:Peroxynitrous Acid; D010100:Oxygen