UNISITE ATP SYNTHESIS IN THYLAKOIDS

作     者：LABAHN, A FROMME, P GRABER, P 

作者机构：UNIV STUTTGARTINST BIOLW-7000 STUTTGART 80GERMANY 

出 版 物：《FEBS LETTERS》 (欧洲生化学会联合会快报)

年 卷 期：1990年第271卷第1-2期

页      面：116-118页

核心收录：

学科分类：0710[理学-生物学] 071010[理学-生物化学与分子生物学] 081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术] 

基　　金：Deutsche Forschungsgemeinschaft  DFG  (Sfb 312) 

主　　题：Chloroplast ATPase H + CF 0 F 1 Uni-site catalysis ATP synthesis CF 0 F 1 H + -translocating ATPase (‘ATP-synthase’) from chloroplasts 

摘      要：Uni-site ATP synthesis was measured with thylakoids. The membrane-bound ATP-synthase, CF 0 F 1 was brought into the active, reduced state by illumination in the presence of thioredoxin, dithiothreitol and phosphate. This enzyme contains two tightly bound ATP per CF o F 1 . ATP was released from the enzyme when ADP was added in substoichiometric amounts during illumination. Experiments with [ 14 C]ADP indicated that after binding the same nucleotide was phosphorylated and released as [ 14 C]ATP, i.e. only one site is involved in ATP-synthesis (uni-site ATP-synthesis ). The two tightly bound ATP are not involved in the catalytic turnover. The rate constant for ADP binding was (4 ± 2) × 10 6 M −1 s −1 . Compared to deenergized conditions the rate constant for ADP binding and that for ATP-release were drastically increased, i.e. membrane energization increased the rate constants for the ATP-synthesis direction.