Heterogeneity of ATP‐hydrolyzing sites on reconstituted CF0F1

FEBS Letters

Fromme, Petra²  Gräber, Peter¹ 

[1] Biologisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 7000 Stuttgart 60, FRG;Max Volmer Institut für Biophysikalische und Physikalische Chemie, Technische Universität Berlin, Str.d. 17. Juni 135 D-1000 Berlin 12, Germany

关键词: Chloroplast;    ATPase;    H+-;    CF0F1;    Reconstitution;    Nucleotide binding site;    Uni-site catalysis;    CF0F1;    H+-translocating ATPase (ATP-synthase) from chloroplasts;   

DOI  :  10.1016/0014-5793(89)81487-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The proton translocating ATP-synthase from chloroplasts, CF₀F₁, was isolated and reconstituted into asolectin liposomes. [γ-³²P]ATP hydrolysis was measured under uni-site conditions. When 1 mM unlabeled ATP was added so that all ATP-binding sites were occupied, [γ-³²P]ATP bound to the first site, was hydrolyzed with a rate of 0.5 ATP/(CF₀F₁ s). In a second experiment, first cold ATP was hydrolyzed under uni-site conditions and then 1 mM [γ-³²P]ATP was added. This allows under otherwise identical conditions the measurement of the rate of ATP hydrolysis catalyzed by the second (and possibly third) site. It resulted in a rate of 80 ATP/(CF₀F₁ s). It is concluded that the catalytic nucleotide binding sites are heterogeneous: there exists one nucleotide binding site which hydrolyzes ATP with a maximal turnover of 0.5/s and another one (or two) which hydrolyze ATP with a turnover of 80/s. The latter one is the catalytic site for maximal turnover.

【 授权许可】

Unknown