Inhibition of chloroplast CF1‐ATPase by vanadate

FEBS Letters

Ophir, R.²  Tadmor, O.²  Lifshitz, Y.²  Carmeli, C.²  Carmeli, S.¹ 

[1] Departments of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel;Departments of Biochemistry, Tel Aviv University, Tel Aviv 69978, Israel

关键词: Transition state;    Enzyme mechanism;    ATP synthase;    Proton pump;    51V NMR;    Tricine;    N-[tris(hydroxymethyl)methyl]glycine;    DTT;    dithiothreitol;    CF1;    coupling factor 1 of chloroplast H+-ATPase;    Chl;    chlorophyll;    NMR;    nuclear magnetic resonance;   

DOI  :  10.1016/0014-5793(92)80120-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Inhibition of ATPase activity by vanadate, having K_½ of 0.5 mM, was demonstrated in the CF₁-ATPase. The Ca²⁺-dependent ATPase activity of the isolated enzyme was inhibited in an allosteric manner by vanadate with a Hill coefficient of 3.19 ± 0.6. Vanadate also inhibited ATPase and Pi—ATP exchange activities of the chloroplast membrane-bound enzyme. Using ⁵¹V NMR it was demonstrated that ATP caused partial release of about 1.87 equivalents while ADP caused additional binding of approximately 1.46 equivalents of vanadate, when added to a solution containing CF₁ equilibrated with vanadate. The relevance of these results to a possible involvement of a pentacovalent phosphate as transition state intermediate in the hydrolysis of ATP by CF₁-ATPase is discussed.

【 授权许可】

Unknown