Verapamil and TMR-Cl do not stimulate the ATPase activity of TMH1,7 mutant P-gp.

The effect of (A) verapamil and (B) TMR-Cl was tested on the ATPase activity of TMH1,7 and compared with WT P-gp [16]. The graphs show vanadate-sensitive ATPase activity of TMH1,7 in the absence of a substrate (basal activity) as 100% and relative activity calculated with increasing concentrations of verapamil (1–50 μM) and TMR-Cl (0.5–25 μM). The data points represent mean values from three independent experiments and error bars depict SD.