title: Inactivation of nitric oxide by uric acid.
abstract: The 1980 identification of nitric oxide (NO) as an endothelial cell-derived relaxing factor resulted in an unprecedented biomedical research of NO and established NO as one of the most important cardiovascular, nervous and immune system regulatory molecule. A reduction in endothelial cell NO levels leading to "endothelial dysfunction" has been identified as a key pathogenic event preceding the development of hypertension, metabolic syndrome, and cardiovascular disease. The reduction in endothelial NO in cardiovascular disease has been attributed to the action of oxidants that either directly react with NO or uncouple its substrate enzyme. In this report, we demonstrate that uric acid (UA), the most abundant antioxidant in plasma, reacts directly with NO in a rapid irreversible reaction resulting in the formation of 6-aminouracil and depletion of NO. We further show that this reaction occurs preferentially with NO even in the presence of oxidants peroxynitrite and hydrogen peroxide and that the reaction is at least partially blocked by glutathione. This study shows a potential mechanism by which UA may deplete NO and cause endothelial dysfunction, particularly under conditions of oxidative stress in which UA is elevated and intracellular glutathione is depleted.
authors.affiliation: Department of Medicine, Division of Nephrology and Hypertension, University of Florida, Gainesville, Florida 32610, USA.
authors.forename: Christine
authors.initials: C
authors.lastname: Gersch
authors.forename: Sergiu P
authors.initials: SP
authors.lastname: Palii
authors.forename: Kyung Mee
authors.initials: KM
authors.lastname: Kim
authors.forename: Alexander
authors.initials: A
authors.lastname: Angerhofer
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Johnson
authors.forename: George N
authors.initials: GN
authors.lastname: Henderson
mesh_terms: D002318:Cardiovascular Diseases / Q000378:metabolism*; D002853:Chromatography, Liquid; D042783:Endothelial Cells; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D013058:Mass Spectrometry; D015394:Molecular Structure; D009569:Nitric Oxide / Q000378:metabolism*; D030421:Peroxynitrous Acid / Q000378:metabolism; D014498:Uracil / Q000031:analogs & derivatives* / Q000378:metabolism; D014527:Uric Acid / Q000378:metabolism*
chemical_list: D030421:Peroxynitrous Acid; D014527:Uric Acid; D009569:Nitric Oxide; D014498:Uracil; C013400:6-aminouracil; D006861:Hydrogen Peroxide; D005978:Glutathione