Brown G C
Department of Biochemistry, University of Cambridge, United Kingdom.
J Biol Chem. 1989 Sep 5;264(25):14704-9.
Several different proton pumps were used to generate a proton motive force (delta p, proton motive force across the mitochondrial inner membrane) in isolated rat liver mitochondria, and the relationship between delta p and pump rate was investigated by titrating with various inhibitors of the pumps. It was found that this relationship was the same for mitochondria respiring on succinate irrespective of whether respiration was inhibited with malonate, antimycin or cyanide, indicating that the relationship was independent of the redox state of the respiratory chain. When delta p was generated by either the cytochrome bc1 complex, cytochrome oxidase, both together, or ATP hydrolysis (and transport), the reaction rates (in moles of electrons or ATP) were in the ratio of close to 3:1.5:1:1, respectively, at all accessible values of delta p. This suggests that the proton stoichiometries (H+/e and H+/ATP, where H+/e is the number of protons translocated vectorially across the inner membrane per electron transferred by the respiratory chain and H+/ATP is the number of protons translocated vectorially per ATP molecule hydrolyzed externally) were in the ratio of close to 1:2:3:3, respectively, at all values of delta p. Possible reasons for previous contradictory results are suggested.
使用几种不同的质子泵在分离的大鼠肝脏线粒体中产生质子动力（Δp，跨线粒体内膜的质子动力），并通过用各种泵抑制剂滴定来研究Δp与泵速率之间的关系。发现琥珀酸呼吸的线粒体中这种关系是相同的，无论呼吸是被丙二酸、抗霉素还是氰化物抑制，这表明该关系与呼吸链的氧化还原状态无关。当由细胞色素bc1复合物、细胞色素氧化酶、两者一起或ATP水解（和转运）产生Δp时，在所有可达到的Δp值下，反应速率（以电子或ATP的摩尔数计）分别接近3:1.5:1:1的比例。这表明在所有Δp值下，质子化学计量比（H⁺/e和H⁺/ATP，其中H⁺/e是呼吸链每转移一个电子在内膜上向量转运的质子数，H⁺/ATP是每水解一个外部ATP分子在内膜上向量转运的质子数）分别接近1:2:3:3的比例。文中还提出了先前矛盾结果的可能原因。
