Fig. 5.

Kinetics of H⁺-ATPase inhibition by carbazole compounds. The initial rate of ATP hydrolysis catalyzed by S. cerevisiae H⁺-ATPase was determined by an NADH-coupled ATPase assay, as described in the Supporting Information. The reaction was initiated by the addition of H⁺-ATPase-containing membranes (arrows with “H⁺-ATPase”) to a pH 7 buffer containing 5 mM ATP. At the indicated times the respective compounds were added to give the final compound concentrations shown in the figure and a final DMSO concentration of 1.1%.