Jourd'heuil D, Mai C T, Laroux F S, Wink D A, Grisham M B
Department of Molecular and Cellular Physiology, Louisiana State University Medical Center, Shreveport 71130, USA.
Biochem Biophys Res Commun. 1998 Mar 17;244(2):525-30. doi: 10.1006/bbrc.1998.8227.
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.
一氧化氮（NO）依赖的硫醇S-亚硝基化生成S-亚硝基硫醇已被认为是体内NO代谢的重要途径。尽管有人提出这些S-亚硝基化化合物对活性氧代谢产物（ROMs）的分解具有抗性，但关于S-亚硝基硫醇与ROMs之间相互作用的信息却非常少。我们发现S-亚硝基谷胱甘肽（GSNO）与超氧阴离子（O₂⁻）迅速反应，生成谷胱甘肽二硫化物以及等摩尔量的亚硝酸盐和硝酸盐。该反应对GSNO为二级反应，对O₂⁻为一级反应，速率方程为-d[GSNO]/dt = 2k₃[GSNO]²[O₂⁻]，其中k₃ = 3 - 6 × 10⁸ M⁻²s⁻¹。此外，GSNO与O₂⁻的反应生成一种强氧化剂作为中间体，能够在无明显NO生成的情况下氧化二氢罗丹明。我们得出结论，O₂⁻可能通过直接促进S-亚硝基硫醇的分解而作为S-亚硝基化反应的生理调节剂。
