Zharova T V, Vinogradov A D
Department of Biochemistry, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119992, Russia.
Biochemistry (Mosc). 2003 Oct;68(10):1101-8. doi: 10.1023/a:1026306611821.
Tightly coupled membranes of Paracoccus denitrificans catalyze oxidative phosphorylation but are incapable of ATP hydrolysis. The conditions for observation and registration of the venturicidin-sensitive ATPase activity of subbacterial particles derived from this organism are described. The ATP hydrolytic activity does not appear after prolonged incubation in the presence of pyruvate kinase and phosphoenol pyruvate (to remove ADP), EDTA (to remove Mg2+) and/or inorganic phosphate, whereas the activity dramatically increases after energization of the membranes. ATP hydrolysis by -activated ATPase is coupled with electric potential formation. Inorganic phosphate prevents and azide promotes a decline of the enzyme activity during ATP hydrolysis. The addition of uncouplers results in rapid and complete inactivation of ATPase. The -dependent ATPase activity increases upon dilution of the membranes. The results are discussed as evidence for the presence of distinct ATP-synthase and ATP-hydrolase states of F(o)F(1) complex in the coupling membranes (Vinogradov, A. D. (1999) Biochemistry (Moscow), 64, 1219-1229). The proposal is made that part of the free energy released from oxidoreduction in the respiratory chain is used to maintain active conformation of the energy-transducing proteins.
反硝化副球菌紧密偶联的膜催化氧化磷酸化，但不能进行ATP水解。本文描述了观察和记录源自该生物体的亚细菌颗粒的对venturicidin敏感的ATP酶活性的条件。在丙酮酸激酶和磷酸烯醇丙酮酸（用于去除ADP）、EDTA（用于去除Mg2+）和/或无机磷酸盐存在下长时间孵育后，ATP水解活性未出现，而在膜通电后活性显著增加。由活化的ATP酶进行的ATP水解与电势形成相偶联。无机磷酸盐可防止ATP水解过程中酶活性下降，而叠氮化物则促进其下降。添加解偶联剂会导致ATP酶迅速且完全失活。依赖于的ATP酶活性在膜稀释时增加。这些结果被作为耦合膜中F(o)F(1)复合物存在不同ATP合酶和ATP水解酶状态的证据进行了讨论（Vinogradov, A. D. (1999) Biochemistry (Moscow), 64, 1219 - 1229）。有人提出，呼吸链中氧化还原释放的部分自由能用于维持能量转导蛋白的活性构象。
