Control of ATP hydrolysis in chloroplasts

FEBS Letters

Strotmann, Heinrich¹  Kleefeld, Sigrid¹  Lohse, Detlev¹ 

[1] Institut für Biochemie der Pflanzen, Universität Düsseldorf, Universitätsstraße 1, D-4000 Düsseldorf, FRG

关键词: ATP synthesis;    ATPase;    Chloroplast;    9-Aminoacridine fluorescence;    Kinetic control;    (Spinach);    DTT;    dithiothreitol;    PMS;    phenazine methosulfate;   

DOI  :  10.1016/0014-5793(87)80938-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Dark ATP hydrolysis catalysed by the membrane-bound preactivated thiol-modified chloroplast ATPase was measured at constant initial ATP concentration and constant initial phosphate potential c _ATP/c _ADP·c_{P i} which was adjusted by inverse variation of the concentrations of ADP and P_i. Under these conditions, the rate of ATP hydrolysis is strongly inhibited as the concentration of ADP is increased and the concentration of P_i is decreased. Inhibition is preferentially caused by ADP-dependent inactivation of ATPase molecules. At low initial ADP concentration, the transmembrane proton gradient generated by effective ATP hydrolysis protects the enzyme from deactivation in spite of progressive accumulation of ADP because energy-dependent release of ADP counteracts its binding. Deactivation due to incorporation of ADP occurs, however, when the proton gradient decreases as a consequence of exhaustion of substrate ATP.

【 授权许可】

Unknown