title: The reaction of S-nitrosoglutathione with superoxide.
abstract: The nitric oxide (NO)-dependent S-nitrosation of thiols to generate S-nitrosothiols has been proposed as an important pathway for the metabolism of NO in vivo. Although it has been suggested that these S-nitrosated compounds are resistant to decomposition by reactive oxygen metabolites (ROMs), very little information is available regarding the interaction between S-nitrosothiols and ROMs. We found that S-nitrosoglutathione (GSNO) rapidly reacted with O2- to generate glutathione disulfide and equimolar quantities of nitrite and nitrate. The reaction was second order with respect of GSNO and first order with respect of O2- with a rate equation of -d[GSNO]/dt = 2k3[GSNO]2[O2-], where k3 = 3 - 6 x 10(8) M-2s-1. In addition, the reaction of GSNO with O2- generated a strong oxidant as an intermediate capable of oxidizing dihydrorhodamine in the absence of the apparent generation of NO. We conclude that O2- may act as a physiological modulator of S-nitrosation reactions by directly promoting the decomposition of S-nitrosothiols.
authors.affiliation: Department of Molecular and Cellular Physiology, Louisiana State University Medical Center, Shreveport 71130, USA.
authors.forename: D
authors.initials: D
authors.lastname: Jourd'heuil
authors.forename: C T
authors.initials: CT
authors.lastname: Mai
authors.forename: F S
authors.initials: FS
authors.lastname: Laroux
authors.forename: D A
authors.initials: DA
authors.lastname: Wink
authors.forename: M B
authors.initials: MB
authors.lastname: Grisham
mesh_terms: D002374:Catalase / Q000378:metabolism; D005978:Glutathione / Q000031:analogs & derivatives* / Q000737:chemistry; D019803:Glutathione Disulfide / Q000737:chemistry; D008956:Models, Chemical; D009569:Nitric Oxide / Q000032:analysis; D009603:Nitroso Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D012235:Rhodamines; D026422:S-Nitrosoglutathione; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000737:chemistry*; D014969:Xanthine Oxidase / Q000378:metabolism
chemical_list: D009603:Nitroso Compounds; D012235:Rhodamines; D013481:Superoxides; D009569:Nitric Oxide; D026422:S-Nitrosoglutathione; D002374:Catalase; D013482:Superoxide Dismutase; D014969:Xanthine Oxidase; D005978:Glutathione; D019803:Glutathione Disulfide