Human glutathione transferase catalysis of the formation of S‐nitrosoglutathione from organic nitrites plus glutathione

Publisher Website
Google Scholar
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, k 2 values of 22.3 and 21.0 M−1 · min−1 were obtained for n‐butyl‐ and amyl nitrites, respectively. Rate enhancements, (kcat /K m × k 2) × 10−4, due to purified human GSH transferases A1−1, A2−2 and Mla−la 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.