Lawford H G, Garland P B
Biochem J. 1972 Dec;130(4):1029-44. doi: 10.1042/bj1301029.
Measurements were made of the stoicheiometry of proton-translocation coupled to NAD(P)H oxidation by several quinones (duroquinone, ubiquinone(0), ubiquinone(1), ubiquinone(2)) in mitochondria from rat liver and ox heart. Observed stoicheiometries of protons translocated per mol of NADH oxidized (-->H(+)/2e(-) ratios; Mitchell, 1966) ranged from 0.75 (rat liver mitochondria with ubiquinone(1)) to 1.55 (ox heart mitochondria with ubiquinone(1) or ubiquinone(2)). Only the rotenone-sensitive pathway of NADH oxidation by quinone was able to support proton translocation. Correction of the observed -->H(+)/2e(-) ratios for the loss of reducing equivalents to the rotenone-insensitive pathway increased their value to approx. 2.0. It is concluded that the rotenone-sensitive NADH- ubiquinone reductase activity of the respiratory chain may be organized in the mitochondrial membrane as a proton-translocating oxidoreduction loop. The number of such loops between NADH and ubiquinone is one, and not two, as initially proposed by Mitchell (1966).
对大鼠肝脏和牛心脏线粒体中几种醌（杜醌、泛醌(0)、泛醌(1)、泛醌(2)）与NAD(P)H氧化偶联的质子转运化学计量进行了测量。观察到每氧化1摩尔NADH转运的质子化学计量（即H⁺/2e⁻比率；Mitchell，1966）范围从0.75（含泛醌(1)的大鼠肝脏线粒体）到1.55（含泛醌(1)或泛醌(2)的牛心脏线粒体）。只有醌介导的对鱼藤酮敏感的NADH氧化途径能够支持质子转运。将观察到的H⁺/2e⁻比率校正为对鱼藤酮不敏感途径中还原当量的损失后，其值增加到约2.0。得出的结论是，呼吸链中对鱼藤酮敏感的NADH -泛醌还原酶活性可能在线粒体内膜中组织成一个质子转运氧化还原环。NADH和泛醌之间这种环的数量是一个，而不是Mitchell（1966）最初提出的两个。
