Inhibition of ATP-driven Proton Translocation by Polyphenols. Proton translocation by membrane vesicles is indicated by the quenching of the fluorescence of ACMA upon the addition of ATP. Membranes without the addition of polyphenols are indicated by CK. In each case, the fluorescence quenching could be eliminated by the addition of FCCP (carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone), a protonophore (results not shown). (A) TF1, (B) TF2A, (C) TF2B, (D) TF3. The final concentrations of inhibitors are indicated in the panels. The results shown are typical from 2 assays of 2 different preparations of membranes.