硝酰基以超氧化物歧化酶可抑制的方式氧化还原型辅酶Ⅱ。
Nitroxyl oxidizes NADPH in a superoxide dismutase inhibitable manner.
作者信息
Reif A, Zecca L, Riederer P, Feelisch M, Schmidt H H
机构信息
Clinical Neurochemistry, Department of Psychiatry and Psychotherapy, Julius-Maximilians-University, Würzburg, Germany.
出版信息
Free Radic Biol Med. 2001 Apr 1;30(7):803-8. doi: 10.1016/s0891-5849(01)00477-4.
Nitric oxide synthases (NOS) convert L-arginine and N(omega)-hydroxy-L-arginine to nitric oxide (*NO) and/or nitroxyl (NO(-)) in a NADPH-dependent fashion. Subsequently, *NO/superoxide (O(2-)-derived peroxynitrite (ONOO(-)) consumes one additional mol NADPH. The related stoichiometry of NO(-) and NADPH is unclear. We here describe that NO(-) also oxidizes NADPH in a concentration-dependent manner. In the presence of superoxide dismutase (SOD), which also converts NO(-) to *NO, nitrite accumulation was almost doubled and no oxidation of NADPH was observed. Nitrate yield from NO(-) was low, arguing against intermediate ONOO(-) formation. Thus, biologically formed NO(-) may function as an effective pro-oxidant unless scavenged by SOD and affect the apparent NADPH stoichiometry of the NOS reaction.
一氧化氮合酶（NOS）以依赖烟酰胺腺嘌呤二核苷酸磷酸（NADPH）的方式将L-精氨酸和N（ω）-羟基-L-精氨酸转化为一氧化氮（*NO）和/或硝酰阴离子（NO⁻）。随后，NO/超氧阴离子（O₂⁻）衍生的过氧亚硝酸根（ONOO⁻）消耗额外1摩尔NADPH。NO⁻与NADPH的相关化学计量关系尚不清楚。我们在此描述NO⁻也以浓度依赖的方式氧化NADPH。在超氧化物歧化酶（SOD）存在的情况下，SOD也将NO⁻转化为NO，亚硝酸盐积累几乎增加了一倍，且未观察到NADPH的氧化。由NO⁻产生的硝酸盐产量较低，这与中间产物ONOO⁻的形成相悖。因此，生物形成的NO⁻可能作为一种有效的促氧化剂发挥作用，除非被SOD清除，并影响NOS反应中明显的NADPH化学计量关系。
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