Transmembrane electrical potential formation by chloroplast ATPase complex (CF1‐CF0) proteoliposomes

Formation of a transmembrane electric potential coupled to ATP hydrolysis is demonstrated in chloroplast ATPase complex containing proteoliposomes. The ATP‐induced signals were detected through absorbance changes of the membrane potential‐responding dye oxonol VI. They were inhibited by the specific energy‐transfer inhibitor, tentoxin and the ionophore valinomycin while stimulated by nigericin. Calibration of the transmembrane potential signal was possible by the application of a proton diffusion potential. The ATP‐induced transmembrane potential was estimated to be 40–50 mV.