Jault J M, Di Pietro A, Falson P, 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. 1989 Jan 31;158(2):392-9. doi: 10.1016/s0006-291x(89)80060-9.
A phenotypic revertant with modified beta-subunits of mitochondrial ATPase-ATP synthase has been obtained for the first time by selection from a beta-less mutant of the yeast Schizosaccharomyces pombe. Contrary to the parental mutant, the phenotypic revertant grows on glycerol, has normal respiratory activity and shows immunodetectable beta-subunits. However the kinetic properties of its submitochondrial particles ATPase activity differ markedly from those of the wild strain. The optimal pH is increased by about one unit. The maximal rate of the revertant ATPase activity at pH 8.5 is 4 to 5-fold lower than that of the wild strain, but it can be greatly increased upon addition of bicarbonate whereas the wild strain is completely insensitive to this anion. Furthermore the revertant ATPase activity is much more sensitive to azide inhibition. The results suggest that ADP dissociation is the rate-limiting step of ATP hydrolysis by the revertant.
首次通过从粟酒裂殖酵母的β亚基缺失突变体中筛选，获得了线粒体ATP酶-ATP合酶β亚基发生修饰的表型回复突变体。与亲本突变体相反，表型回复突变体能够在甘油上生长，具有正常的呼吸活性，并且可通过免疫检测到β亚基。然而，其亚线粒体颗粒ATP酶活性的动力学特性与野生菌株明显不同。最佳pH值提高了约一个单位。回复突变体ATP酶活性在pH 8.5时的最大速率比野生菌株低4至5倍，但加入碳酸氢盐后其活性可大大提高，而野生菌株对该阴离子完全不敏感。此外，回复突变体的ATP酶活性对叠氮化物抑制更为敏感。结果表明，ADP解离是回复突变体ATP水解的限速步骤。
