Frerman F E
Biochim Biophys Acta. 1987 Sep 10;893(2):161-9. doi: 10.1016/0005-2728(87)90035-1.
Submitochondrial particles catalyze the reduction of electron-transfer flavoprotein (ETF) by NADH and succinate under anaerobic conditions in reactions that are totally inhibited by rotenone and thenoyl trifluoroacetone, respectively. The particles also catalyze the ATP-dependent reduction of NAD+ by enzymatically reduced ETF. The latter reaction is inhibited by rotenone and carbonyl cyanide chlorophenylhydrazone and all three reactions are inhibited by antibody to electrontransfer flavoprotein-ubiquinone oxidoreductase (ETF-QO). These observations indicated that ETF-QO reacts with the pool of ubiquinone that is reduced by NADH and succinic dehydrogenases. Consistent with this hypothesis, NADH- and succinic-ETF reductase activities are inhibited 99% in ubiquinone-depleted particles, and reincorporation of exogenous ubiquinone restores at least 90% of these activities. Reduction of the bc1 complex by ETF and acyl CoA oxidase activity are also inhibited by antibody to ETF-QO. Myxothiazole and antimycin which inhibit the quinonol oxidation and quinone reduction sites, respectively, in the bc1 complex also inhibit electron transport from ETF-QO through the complex according to current models of the Q-cycle (Rich, P.R. (1986) J. Bioenerg. Biomembranes 18, 145-156). The results show that ETF-QO is an obligatory component of the electron transport pathway between ETF and the ubiquinone pool and suggest a mechanism for the steady-state turnover of ETF-QO.
线粒体亚基颗粒在厌氧条件下催化NADH和琥珀酸将电子传递黄素蛋白（ETF）还原，这两个反应分别被鱼藤酮和噻吩甲酰三氟丙酮完全抑制。这些颗粒还催化酶促还原的ETF将NAD⁺进行ATP依赖性还原。后一个反应被鱼藤酮和羰基氰化物间氯苯腙抑制，并且所有这三个反应都被电子传递黄素蛋白 - 泛醌氧化还原酶（ETF - QO）抗体抑制。这些观察结果表明，ETF - QO与由NADH和琥珀酸脱氢酶还原的泛醌池发生反应。与此假设一致，在泛醌耗尽的颗粒中，NADH - 和琥珀酸 - ETF还原酶活性被抑制99%，重新掺入外源性泛醌可恢复至少90%的这些活性。ETF对bc1复合物的还原以及酰基辅酶A氧化酶活性也被ETF - QO抗体抑制。根据当前的Q循环模型，分别抑制bc1复合物中醌醇氧化和醌还原位点的黏噻唑和抗霉素也抑制从ETF - QO通过该复合物的电子传递（Rich，P.R.（1986年）《生物能量学与生物膜杂志》18，145 - 156）。结果表明，ETF - QO是ETF与泛醌池之间电子传递途径的必需组分，并提出了ETF - QO稳态周转的机制。
