Figure 3.

(A) Dependence of the total membrane conductance on membrane composition and applied voltage. hUCP2 concentration was ∼7 μg/mg of lipid. Buffer solution contained 50 mM K₂SO₄, 25 mM TES, 0.6 mM EGTA at pH 7.35, and T = 37°C. Each point with a vertical bar represents a mean value and a standard deviation from 9–18 experiments, carried out on three different days. (B) UCP1-mediated membrane conductance in the presence of arachidonic (AA, 20:4) and oleic (OA, 18:1) acids at different ΔΨ_m. Dashed lines represent the fit of the Eq. 1 to the experimental data. Inset: Comparison of G calculated at zero potential. Bilayer lipid membranes were made from E. coli total lipid extract. The concentration of AA and OA was 15 mol %, mUCP1 (charge 2) ∼2.6 μg/mg of lipid. Buffer solution contained 50 mM Na₂SO₄, 25 mM TES, 0.6 mM EGTA at pH 7.0.