EFFECTS OF VALINOMYCIN AND NIGERICIN ON THE ATP-DRIVEN TRANSHYDROGENASE REACTION CATALYZED BY RECONSTITUTED TRANSHYDROGENASE-ATPase VESICLES*

Reconstituted transhydrogenase-ATPase vesicles obtained with purified beef heart transhydrogenase and oligomycin-sensitive ATPase were investigated with respect to the mode of interaction between the two proton pumps, with special reference to the rela- tive contributions of the membrane potential and pro- ton gradient using valinomycin and nigericin in the presence of potassium. In the absence of ionophores and at low ATP concentrations, below 20