S-Transnitrosation reactions are involved in the metabolic fate and biological actions of nitric oxide.
S-Transnitrosation reactions are involved in the metabolic fate and biological actions of nitric oxide.
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发表时间：
1998-02
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通讯作者：
Zhenguo Liu;M. Rudd;Jane E. Freedman;Joseph Loscalzo
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作者：
Zhenguo Liu;M. Rudd;Jane E. Freedman;Joseph Loscalzo
S-亚硝基硫醇是一组有效的生物活性化合物，通过一氧化氮（NO）与硫醇在氧气存在下反应形成。这些化合物在体内天然存在，稳定NO并增强其生物学效应。S-亚硝基谷胱甘肽是细胞内最丰富的S-亚硝基硫醇，其形成的动力学有利于从头合成。在这项分析中，我们研究了S-亚硝基硫醇的形成S-transnitrosation，或交换-NO的硫原子之间的-H;我们合成S-亚硝基-谷胱甘肽-琼脂糖4 B珠（SNO-4 B）作为试剂，其中测量S-transnitrosation反应。在用酸化的亚硝酸盐对珠进行S-亚硝化后，我们检测到最大值为1.57 +/- 0.24 pmol NO/珠（n = 5）。S-NO键的稳定性取决于温度，但在5至9的范围内不取决于pH值（除了在37 ℃时pH值为9），估计t1/2在22 ℃时为30小时，在4 ℃时约为2周。我们证明，SNO-4 B转移-NO谷胱甘肽和半胱氨酸迅速和pH依赖性的方式。在室温下，在pH 5.0、7.4和9.0时，-NO从SNO-4 B转移到谷胱甘肽的初始速率分别为0.53、3.03和5.14 μ M/min（P <0.05）。在相同条件下，-NO转化为半胱氨酸的初始速率为0。72、3.71和4.69 μ M/min（P <0.05）。SNO-4 B和牛血清白蛋白之间没有明显的S-转亚硝化反应。我们进一步证明，SNO-4 B在无血浆系统中引起显著的血管扩张和血小板抑制反应，并激活血小板可溶性鸟苷酸环化酶。这些数据表明一种机制，通过它来解释的代谢命运和分布的NO之间的硫醇池在脉管系统中，并牵连在细胞表面的S-transnitrosation在NO信号转导。
S-Nitrosothiols are a group of potent, bioactive compounds that form through the reaction of nitric oxide (NO) with thiols in the presence of oxygen. These compounds are naturally occurring in vivo, stabilize NO and potentiate its biological effects. S-Nitrosoglutathione is the most abundant intracellular S-nitrosothiol, and the kinetics for its formation favors de novo synthesis. In this analysis, we studied the formation of S-nitrosothiols by S-transnitrosation, or exchange of -NO for -H between sulfur atoms; we synthesized S-nitroso-glutathionyl-Sepharose 4B beads (SNO-4B) as a reagent with which to measure S-transnitrosation reactions. We detected a maximum of 1.57 +/- 0.24 pmol NO/bead (n = 5) after S-nitrosation of the beads with acidified nitrite. The stability of the S-NO bond was dependent on temperature, but not pH over the 5 to 9 range (except at pH 9 at 37 degrees ), with an estimated t1/2 of 30 hr at 22 degrees C and of approximately 2 wk at 4 degrees C. We demonstrated that SNO-4B transfers -NO to glutathione and to cysteine rapidly and in a pH-dependent manner. The initial rate of transfer of -NO from SNO-4B to glutathione at room temperature was 0.53, 3.03 and 5.14 microM/min at pH 5.0, 7.4 and 9.0, respectively (P < .05). Under the same conditions, the initial rate of -NO transfer to cysteine was 0. 72, 3.71 and 4.69 microM/min at pH 5.0, 7.4 and 9.0, respectively (P < .05). There was no appreciable S-transnitrosation between SNO-4B and bovine serum albumin. We further demonstrated that SNO-4B evokes significant vasodilator and platelet inhibitory responses in plasma-free systems and activates platelet soluble guanylyl cyclase. These data suggest a mechanism by which to explain the metabolic fate and distribution of NO among thiol pools in the vasculature, and implicate S-transnitrosation at the cell surface in NO signal transduction.