Electron competition process in respiratory chain: Regulatory mechanisms and physiological functions
Electron competition process in respiratory chain: Regulatory mechanisms and physiological functions
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DOI：
10.1016/j.bbabio.2010.01.030
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发表时间：
2010-06-01
影响因子：
4.3
通讯作者：
Devin, Anne
中科院分区：
文献类型：
--
作者：
Rigoulet, Michel;Mourier, Arnaud;Devin, Anne
在从酵母酿酒酵母分离的线粒体中，在非磷酸化条件下，我们以前已经表明，有一个来自外部NADH脱氢酶，Nde1p的电子的方式的权利。在这项工作中，我们表明，电子竞争过程是相同的生理条件下，即氧化磷酸化。这种竞争产生了胞质NADH再氧化的优先权。此外，这种电子竞争过程与能量浪费（“主动泄漏”）相关，当氧化还原压力增加时，该能量浪费允许氧化还原当量氧化的增加。当这种氧化还原压力降低时，即在磷酸化条件下，大部分这种能量浪费得到缓解。通过研究呼吸链超分子组织或电子竞争活性的突变株，我们表明，呼吸链超分子组织是不负责的电子竞争过程。此外，我们显示了两个不同的呼吸速率和醌氧化还原状态之间的关系，似乎表明两个醌池，参与电子的方式的权利。事实上，还原程度较高的池与外部电子通道相关，而还原程度较低的池与内部电子通道相关。(C)2010 Elsevier B.V.保留所有权利。
In mitochondria isolated from the yeast Saccharomyces cerevisiae, under non-phosphorylating conditions, we have previously shown that there is a right of way for electrons coming from the external NADH dehydrogenase, Nde1p. In this work, we show that the electron competition process is identical under more physiological conditions i.e. oxidative phosphorylation. Such a competition generates a priority for cytosolic NADH reoxidation. Furthermore, this electron competition process is associated with an energy wastage (the "active leak") that allows an increase in redox equivalent oxidation when the redox pressure increases. When this redox pressure is decreased, i.e. under phosphorylating conditions, most of this energy wastage is alleviated. By studying mutant strains affected either in respiratory chain supramolecular organization or in electron competition activity, we show that the respiratory chain supramolecular organization is not responsible for the electron competition processes. Moreover, we show two distinct relationships between the respiratory rate and the quinone redox state that seem to indicate two quinone pools that are involved in the electron right of way. Indeed, the more reduced pool would be associated to the electron right of way for the external dehydrogenases whereas the less reduced pool would be associated to the electron right of way for the internal dehydrogenases. (C) 2010 Elsevier B.V. All rights reserved.