Cl⁻ efflux rates. (A) Representative “Cl⁻-dump” traces from the indicated transporters reconstituted at 5 µg/mg lipid, except for “control” trace from protein-free liposomes. Passive Cl⁻ efflux was triggered by the addition of Vln/FCCP and followed with a Cl⁻ electrode. Trapped Cl⁻ was released with 50 mM octylglucoside at the end of the experiment (abrupt upward deflections). Cl⁻ traces are normalized to the final concentration after the disruption of the liposomes. (B) Unitary turnover rate, γ, plotted in order of proton-pumping activities reported in Fig. 1. Each bar represents mean ± SEM of three to four runs.