Fig. 1.

Penetrating cations mediate protonophorous effect of fatty acids in BLMs. (A,B) The BLM was formed from Ambersep-purified synthetic DPPC supplemented with 1 mg palmitate per 20 mg DPPC. (A) KOH was added to one compartment to create ΔpH and then to the other compartment to equalize the pH values in the two compartments; incubation mixture, 10 mM Tris, 10 mM MES, 10 mM KCl, and 1 µM SkQ1. (B) Comparison of effects of 1 µM C₁₂TPP, 1 µM C₁₀TPP, and 10 μM CTMA on Δψ generation induced by pH shift from pH 6 to 7; for incubation mixture, see (A). (C,D) Palmitate was added in the incubation medium on both sides of the BLM-separated compartments. (C) and (D), Δψ as a function of palmitate and SkQ1 concentrations in the incubation mixture, respectively; for incubation mixture and the pH shift, see Fig. S2E; in (C), 0.5 μM C₁₂TPP was present. In (B), palmitate concentration was 20 μM.