fig6

Figure 6. ABCB1 ATPase activity in NIH-MDR1-G185 cells (filled symbols) and inside-out plasma membrane vesicles (open symbols) induced by three drugs. (A-C) ATPase activity expressed as percent of the basal value in the absence of drugs. (D-F) ATPase activity expressed as protons (i.e., lactic acid) or phosphate released per ABCB1 per second. Calculations are based on the expression level of ABCB1 determined for NIH-MDR1-G185 cells [124]. (A and D) Verapamil ; (B and E) diltiazem
, and (C and F)
daunorubicin. Lines are fits to Supplementary Equation 12. Standard deviations are shown (taken from Ref.[69]). With copyright permission from BBA.