Electron-paramagnetic resonance spectroscopy using N-methyl-D-glucamine dithiocarbamate iron cannot discriminate between nitric oxide and nitroxyl: Implications for the detection of reaction products for nitric oxide synthase
Electron-paramagnetic resonance spectroscopy using N-methyl-D-glucamine dithiocarbamate iron cannot discriminate between nitric oxide and nitroxyl: Implications for the detection of reaction products for nitric oxide synthase
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DOI：
10.1016/s0891-5849(00)00156-8
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发表时间：
2000-03-01
影响因子：
7.4
通讯作者：
Schmidt, HHHW
中科院分区：
文献类型：
--
作者：
Komarov, AM;Wink, DA;Schmidt, HHHW
除非添加高浓度的超氧化物歧化酶（SOD），否则纯化的神经元一氧化氮合酶（NOS）不会产生一氧化氮（NO），这表明硝酰基（NO（-））或相关分子是NOS的主要反应产物，NOS依赖SOD转化为NO。使用电子顺磁共振波谱和 N-甲基-D-葡萄糖胺二硫代氨基甲酸铁 (Fe-MGD) 作为 NO 捕获物的实验对这一假设提出了质疑。虽然NOS和NO供体S-亚硝基-N-乙酰基-青霉胺产生电子顺磁共振信号，但NO供体Angeli盐(AS)却没有。 AS 是一种不稳定的化合物，会迅速水解为亚硝酸盐，但缺乏表明 AS 完好无损的重要阳性对照实验。在重新研究这一重要实验时，我们发现 S-亚硝基-N-乙酰基-青霉胺和 AS 中存在相同的 MGD(2)-Fe-NO 复合物，但亚硝酸盐中却没有。此外，即使在不存在 SOD 的情况下，AS 产生的 MGD(2)-Fe-NO 复合物的产量也是化学计量的。因此，MGD(2)-Fe 直接检测 NO(-)，从 MGD(2)-Fe-NO 复合物得出的关于初级 NOS 产物（NO、NO(-) 或相关 N-氧化物）性质的任何结论都是无效的。因此，NOS可以形成NO(-)或相关的N-氧化物而不是NO。 (C) 2000 爱思唯尔科学公司。
Purified neuronal nitric oxide synthase (NOS) does not produce nitric oxide (NO) unless high concentrations of superoxide dismutase (SOD) are added, suggesting that nitroxyl (NO(-)) or a related molecule is the principal reaction product of NOS, which is SOD-dependently converted to NO. This hypothesis was questioned by experiments using electron paramagnetic resonance spectroscopy and iron N-methyl-D-glucamine dithiocarbamate (Fe-MGD) as a trap for NO. Although NOS and the NO donor S-nitroso-N-acetyl-penicillamine produced an electron paramagnetic resonance signal, the NO- donor, Angeli's salt (AS) did not. AS is a labile compound that rapidly hydrolyzes to nitrite, and important positive control experiments showing that AS was intact were lacking. On reinvestigating this crucial experiment, we find identical MGD(2)-Fe-NO complexes both from S-nitroso-N-acetyl-penicillamine and AS but not from nitrite. Moreover, the yield of MGD(2)-Fe-NO complex from AS was stoichiometric even in the absence of SOD. Thus, MGD(2)-Fe directly detects NO(-), and any conclusions drawn from MGD(2)-Fe-NO complexes with respect to the nature of the primary NOS product (NO, NO(-), or a related N-oxide) are invalid. Thus, NOS may form NO(-) or related N-oxides instead of NO. (C) 2000 Elsevier Science Inc.