心磷脂对细胞色素C氧化酶质子泵功能的影响

 用胆酸盐透析法将猪心线粒体细胞色素C氧化酶重组在含心磷脂和二肉豆寇磷脂酰胆碱的脂质体上,以还原态细胞色素C作为酶反应底物,记录脂酶体囊泡外介质液pH的变化,pH下降幅度可以反映细胞色素C氧化酶质子泵的功能。 心磷脂含量不同的细胞色素C氧化酶脂酶体质子泵功能不同。心磷脂含量在10％—40％(w/w)范围内,随心磷脂含量增高,该酶质子泵功能增强;当心磷艏含量超过50％时,该酶质子泵功能却随心磷脂含量的增加表现出下降的趋势。阿霉素可以与心磷脂紧密结合,抑制细胞色素C氧化酶的质子泵功能。然而,少量阿霉素却能增强含70％心磷脂的脂酶体的质子泵功能。

A Study of the Effect of Cardiolipin on Cytochrome C Oxidase Proton-Pumping Function

Cytochrome c oxidase from pig heart was incorporated into liposomes containing cardiolipin and DMPC with cholate dialysis method. With reduced cytochrome c as substrate the change of pH in the medium of proteoliposomes was recorded by a fast recording pH meter and showed cytochrome c oxidase proton-pumping function. Cytochrome c oxidase proton-pumping function was enhanced while concentration of cardiolipin was increased within the range from 10% to 40%. When cardiolipin concentration was more than 50%, the enzyme proton-pumping function was no longer increased. Adriamycin could cojoin with cardiolipin and inhibit proton-pumping function. But proteoliposomes containing 70% cardiolipin, low concentration of adri-amycin could enhance the proton-pumping function.