Falson P, Di Pietro A, Darbouret D, Jault J M, Gautheron D C, Boutry M, Goffeau A
Laboratoire de Biologie et Technologie des Membranes du CNRS, Université Claude Bernard de Lyon, Villeurbanne, France.
Biochem Biophys Res Commun. 1987 Nov 13;148(3):1182-8. doi: 10.1016/s0006-291x(87)80257-7.
A partial revertant from a mutant with modified alpha subunits of mitochondrial ATPase-ATPsynthase has been obtained for the first time from the yeast Schizosaccharomyces pombe. The purified F1 contains a lower amount of endogenous nucleotides as compared to the wild-strain enzyme. In contrast to the wild-type, the F1 ATPase activity from the revertant does not exhibit bicarbonate-sensitive negative cooperativity. The revertant Michaelis constant for Mg-ATP is very similar to that of normal F1 in the presence of bicarbonate while the Vm is slightly lower. The revertant enzyme is much less sensitive to inhibitions by ADP and by azide. It is proposed that the lack of negative cooperativity of revertant F1 ATPase activity is due to lower affinity for ADP, the release of which is no longer the rate-limiting step.
首次从粟酒裂殖酵母中获得了线粒体ATP酶 - ATP合酶α亚基发生修饰的突变体的部分回复子。与野生型菌株的酶相比，纯化后的F1所含内源性核苷酸量更低。与野生型不同，回复子的F1 ATP酶活性不表现出对碳酸氢盐敏感的负协同性。在存在碳酸氢盐的情况下，回复子对Mg-ATP的米氏常数与正常F1非常相似，而最大反应速度略低。回复子酶对ADP和叠氮化物的抑制作用敏感度低得多。有人提出，回复子F1 ATP酶活性缺乏负协同性是由于对ADP的亲和力较低，ADP的释放不再是限速步骤。
