Mathai J C, Sitaramam V
Department of Zoology, University of Poona, Pune, India.
Biochim Biophys Acta. 1989 Sep 28;976(2-3):214-21. doi: 10.1016/s0005-2728(89)80233-6.
The empirically observed relationship between the activity of membrane-bound enzyme systems and transporters and the external osmotic pressure offered a direct method to assess the reflection coefficients to polyols in respiring mitochondria. These osmotically modulated reaction rates varied with the molecular mass of the external polyol similar to volume and solute fluxes across dialysis membranes. The equivalent pore radii of mitochondria were shown to increase with respiration (and temperature) and decrease on addition of the uncoupler, 2,4-dinitrophenol. The magnitude of the induced porosity in the inner membrane was large enough to render the chemiosmotic mechanism inoperable in well-coupled rat liver mitochondria.
通过实验观察到的膜结合酶系统和转运蛋白的活性与外部渗透压之间的关系，为评估呼吸线粒体中多元醇的反射系数提供了一种直接方法。这些受渗透压调节的反应速率随外部多元醇的分子量而变化，类似于透析膜上的体积和溶质通量。线粒体的等效孔径随呼吸作用（和温度）增加，添加解偶联剂2,4-二硝基苯酚后减小。内膜中诱导孔隙率的大小足以使化学渗透机制在偶联良好的大鼠肝脏线粒体中无法发挥作用。
