Diphenyleneiodonium inhibits reduction of iron-sulfur clusters in the mitochondrial NADH-ubiquinone oxidoreductase (Complex I).
Diphenyleneiodonium inhibits reduction of iron-sulfur clusters in the mitochondrial NADH-ubiquinone oxidoreductase (Complex I).
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二亚苯基碘鎓抑制线粒体 NADH-泛醌氧化还原酶（复合物 I）中铁硫簇的还原。
DOI：
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发表时间：
1994
影响因子：
4.8
通讯作者：
M. Wikström
中科院分区：
文献类型：
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作者：
A. Majander;M. Finel;M. Wikström
二苯基碘鎓（DPI）抑制Fe-S簇底物侧的线粒体NADH-泛醌氧化还原酶（复合物I）。在抑制的补充NADH的状态下，所有的Fe-S簇被氧化，而蛋白质结合的FMN的还原-氧化差谱可以被可视化。其特征在于在370和450 nm处有谷值，在500-700 nm区域吸光度略有增加。DPI可能与FMN发生不可逆反应，因为FMN的氧化即使在从酶中提取后也被阻断。抑制需要在NADH和DPI存在下预孵育酶。NADH/NAD+比率或pH越低，或NAD+/DPI比率越高，抑制所需的DPI越多。NAD+和DPI显然在争夺一个共同的网站。泛醌和二氯酚靛酚还原酶活性完全阻断DPI，而铁氰化物还原酶活性被抑制75%。发现与复合物I和两个鱼藤酮不敏感的制剂，亚复合物I λ和黄素蛋白馏分类似的结果。DPI还抑制细菌NADH-泛醌氧化还原酶-1（NDH-1）在副球菌和大肠杆菌膜中的NADH氧化。
Diphenyleneiodonium (DPI) inhibits the mitochondrial NADH-ubiquinone oxidoreductase (Complex I) on the substrate side of the Fe-S clusters. In the inhibited NADH-supplemented state all of the Fe-S clusters are oxidized, whereas the reduced minus oxidized difference spectrum of the protein-bound FMN can be visualized. It is characterized by troughs at 370 and 450 nm and a small increase of absorbance in the 500-700-nm region. DPI probably reacts irreversibly with FMN, because oxidation of FMN is blocked even after its extraction from the enzyme. Inhibition requires preincubation of enzyme in the presence of NADH and DPI. The lower the NADH/NAD+ ratio or the pH, or the higher the NAD+/DPI ratio, the more DPI is required for inhibition. NAD+ and DPI apparently compete for a common site. Both ubiquinone and dichlorophenolindophenol reductase activities are fully blocked by DPI, whereas the ferricyanide reductase activity is inhibited by 75%. Similar results were found with Complex I and two rotenone-insensitive preparations, subcomplex I lambda and the flavoprotein fraction. DPI also inhibits NADH oxidation by bacterial NADH-ubiquinone oxidoreductase-1 (NDH-1) in membranes of Paracoccus denitrificans and Escherichia coli.