FIG. 1.

Membrane potential generation in RSO (A) and ISO (B) membrane vesicles of A. aceti IFO 3283. The reaction mixture contained RSO membrane vesicles (A: 38.5 μg of protein) or ISO membrane vesicles (B: 415 μg of protein) in 50 mM KPB (pH 6.5) containing 5 mM MgSO₄. The reaction was started by the addition of 10 mM lactate, followed by the addition of 0.025 μM nigericin (Nig) and 1 μM valinomycin (Val) or 2 mM KCN. Ten micromolar CCCP was also added before the addition of lactate. Fluorescence quenching of diS-C₃-(5) (A) and diBA-C₂-(5) (B) was monitored as described in Materials and Methods.