Summary of effects of mutations and sulfhydryl modification. The percent change was calculated using the following equation: (I_MTS − I_before) / I_before × 100% for steady-state VRAC currents measured at 100 (A) and −100 mV (B), respectively. The effect of MTSES⁻ is shown in open bars, the peak stimulation after applying MTSET⁺ is shown as MTSET_peak, and the stabilized level in MTSET⁺ is shown as MTSET_stable. (C) Effect of MTS treatment on E_rev. The change in E_rev is the difference between E_rev before and after MTS treatment. The reversal potential of F81E currents (without MTS treatment) is shown with a cross-hatched bar. (D) Rectification ratio of native, F81C, and F81E VRAC currents. The rectification ratio was calculated as the absolute value of the VRAC current at +100 mV divided by the current at −100 mV for native, F81C, and F81E currents. Data are represented in mean ± SEM. **, significantly different at P < 0.01 level.