Reactivity of hydrogen sulfide with peroxynitrite and other oxidants of biological interest
Reactivity of hydrogen sulfide with peroxynitrite and other oxidants of biological interest
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DOI：
10.1016/j.freeradbiomed.2010.10.705
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发表时间：
2011-01-01
影响因子：
7.4
通讯作者：
Alvarez, Beatriz
中科院分区：
文献类型：
--
作者：
Carballal, Sebastian;Trujillo, Madia;Alvarez, Beatriz
硫化氢（H2S）是一种内源性产生的气体，也可以外源性施用。它调节生理功能，并已报道细胞保护作用。为了评估可能的抗氧化作用，我们研究了硫化氢与几种单电子和双电子氧化剂的反应性。与过氧亚硝酸根直接反应的速率常数为（4.8 +/- 1.4）x 103 M-1 s（-1）（pH 7.4，37 ℃）。在低硫化氢浓度下，过氧亚硝酸盐氧化导致氧消耗，与引发自由基链式反应的单电子氧化一致。因此，脉冲辐解研究表明，硫化氢与二氧化氮在pH 6时的反应速率为（3.0 +/- 0.3）x 10（6）M-1 s（-1），在pH 7.5时的反应速率为（1.2 +/- 0.1）x 10（7）M-1 s（-1）（25 ℃）。硫化氢与过氧化氢、次氯酸盐和牛磺酸氯胺的反应速率常数分别为0.73 +/- 0.03、（8 +/- 3）x 10（7）和303 +/- 27 M-1 s（-1）（pH 7.4，37 ℃）。硫化氢的反应性进行了比较，低分子量的硫醇，如半胱氨酸和谷胱甘肽。考虑到内源性硫化氢的组织浓度较低，与氧化剂的直接反应可能不能完全解释其保护作用。(C)2010年爱思唯尔公司All rights reserved.
Hydrogen sulfide (H2S) is an endogenously generated gas that can also be administered exogenously. It modulates physiological functions and has reported cytoprotective effects. To evaluate a possible antioxidant role, we investigated the reactivity of hydrogen sulfide with several one- and two-electron oxidants. The rate constant of the direct reaction with peroxynitrite was (4.8 +/- 1.4) x 103 M-1 s(-1) (pH 7.4, 37 degrees C). At low hydrogen sulfide concentrations, oxidation by peroxynitrite led to oxygen consumption, consistent with a one-electron oxidation that initiated a radical chain reaction. Accordingly, pulse radiolysis studies indicated that hydrogen sulfide reacted with nitrogen dioxide at (3.0 +/- 0.3) x 10(6) M-1 s(-1) at pH 6 and (1.2 +/- 0.1) x 10(7) M-1 s(-1) at pH 7.5 (25 degrees C). The reactions of hydrogen sulfide with hydrogen peroxide, hypochlorite, and taurine chloramine had rate constants of 0.73 +/- 0.03, (8 +/- 3) x 10(7), and 303 +/- 27 M-1 s(-1), respectively (pH 7.4, 37 degrees C). The reactivity of hydrogen sulfide was compared to that of low-molecular-weight thiols such as cysteine and glutathione. Considering the low tissue concentrations of endogenous hydrogen sulfide, direct reactions with oxidants probably cannot completely account for its protective effects. (C) 2010 Elsevier Inc. All rights reserved.