title: Human glutathione transferase catalysis of the formation of S-nitrosoglutathione from organic nitrites plus glutathione.
abstract: The kinetics of spontaneous and human glutathione transferase catalysed formation of S-nitrosoglutathione (GSNO) from glutathione (GSH) and n-butyl- or amyl nitrite have been studied. At physiological pH and temperature, k2 values of 22.3 and 21.0 M-1.min-1 were obtained for n-butyl- and amyl nitrites, respectively. Rate enhancements, (kcat/Km x k2) x 10(-4), due to purified human GSH transferases A1-1, A2-2 and M1a-1a were, respectively, 7.00, 2.94 and 10.6 for n-butyl nitrite and 121, 3.92 and 34.5 for amyl nitrite. GSH transferase P1-1 showed no detectable catalysis of the formation of GSNO. The data suggest that the presence of GSTs A1-1, A2-2 or M1-1 contribute substantially to intracellular metabolism of alkyl nitrites to GSNO. The results may be significant with regard to the immunotoxicity of alkyl nitrites.
authors.affiliation: Department of Biochemistry and Molecular Biology, University College London, UK.
authors.forename: D J
authors.initials: DJ
authors.lastname: Meyer
authors.forename: H
authors.initials: H
authors.lastname: Kramer
authors.forename: B
authors.initials: B
authors.lastname: Ketterer
mesh_terms: D002384:Catalysis; D005978:Glutathione / Q000031:analogs & derivatives* / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism*; D006801:Humans; D007668:Kidney / Q000201:enzymology; D008099:Liver / Q000201:enzymology; D009573:Nitrites / Q000378:metabolism*; D009603:Nitroso Compounds / Q000378:metabolism*; D026422:S-Nitrosoglutathione
chemical_list: D009573:Nitrites; D009603:Nitroso Compounds; D026422:S-Nitrosoglutathione; D005982:Glutathione Transferase; D005978:Glutathione