Ca^(2+)、CaM及CaM拮抗剂对粟酒裂殖酵母质膜H^+-ATP酶活性的影响

Effects of Ca^(2+),CaM and CaM Inhibitors on Activity of Schizosaccharomyces pombe Plasma Membrane H^+-ATPase

经差速离心,酸处理,蔗糖密度梯度离心制备粟酒裂殖酵母(Schizosaccharomyces pom be)质膜H+-ATP酶,以研究Ca2+、CaM以及CaM拮抗剂对纯化的质膜H+-ATP酶活性的影响.结果表明Ca2+强烈的抑制该酶的活性,而CaM对该酶的活性没有影响,但TFP与Compound R24571这两类CaM拮抗剂又都能强烈地抑制该酶的活性.推测TFP等抑制该酶的活性不是通过与CaM结合作为CaM的拮抗剂竞争性抑制该酶的活性,而是直接对该酶发生作用或者通过磷脂或其它的CaM依赖性的膜蛋白间接对该酶产生作用.

The Schizosaccharomyces pombe plasma membrane H^＋ -ATPases are obtained by differential centrifugation, acid treatment and isopycnic centrifugation in a discontinuous sucrose gradient to study the effects of Ca^2＋ ,CaM and CaM inhibitors on activity of purified plasma membrane H^＋ -ATPase. The resuits show that Ca^2＋ strongly inhibit the enzyme activity while CaM has no effect on it, and that both the CaM inhibitor TFP and Compound R24571 strongly inhibit the enzyme activity. It is inferred that TFP and Compound R24571 ＇ s inhibition of H^＋ -ATPases enzyme activity is not made by combining TFP with CAM to form CaM inhibitors, but through direct interaction, or mediated by phospholipids and other CaM - dependent membrane protein.