Bulygin V V, Vinogradov A D
Department of Biochemistry, School of Biology, Moscow State University, USSR.
FEBS Lett. 1988 Aug 29;236(2):497-500. doi: 10.1016/0014-5793(88)80085-1.
Preincubation of submitochondrial particles with ADP in the presence of Mg2+ results in the complete inhibition of ATPase which is slowly reactivated in the assay mixture containing ATP and the ATP regenerating system. Significantly, the rate of activation increases as the concentration of ADP in the preincubation mixture rises from 1 microM to 20 microM and reaches a constant value at higher ADP concentrations. The first-order rate constant for the activation process in the assay mixture is ATP-dependent at any level of inhibitory ADP. The data obtained strongly suggest that two ADP-specific inhibitory sites and one ATP-specific hydrolytic site are present in F1-F0 ATPase. Taking into account the (3 alpha.3 beta).gamma.delta.epsilon structure of F1, it is concluded that the synchronous discharge of ADP from two inhibitory sites during the activation occurs after ATP binds to the ATPase catalytic site.
在Mg2+存在的情况下，亚线粒体颗粒与ADP预孵育会导致ATP酶完全被抑制，而在含有ATP和ATP再生系统的测定混合物中，ATP酶会缓慢重新激活。值得注意的是，随着预孵育混合物中ADP浓度从1微摩尔升至20微摩尔，激活速率增加，并且在更高的ADP浓度下达到恒定值。在任何抑制性ADP水平下，测定混合物中激活过程的一级速率常数都依赖于ATP。所获得的数据有力地表明，F1-F0 ATP酶中存在两个ADP特异性抑制位点和一个ATP特异性水解位点。考虑到F1的(3α.3β).γ.δ.ε结构，可以得出结论，在激活过程中，当ATP与ATP酶催化位点结合后，两个抑制位点的ADP会同步释放。
