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. 2005 May 24;388(Pt 2):563–571. doi: 10.1042/BJ20041999

Figure 2. Effect of increasing concentrations of orthovanadate on the P-gp ATPase activity (A) and distribution of the P-gp ATPase activity (B) in different membrane fractions from CEM/VLB5 cells.

Figure 2

Membrane fractionation and measurement of P-gp ATPase activity was performed as described in the Materials and methods section. (A) P-gp ATPase activity from CEM/VLB0.45 cell membranes (open bars) and CEM/VLB5 cell membranes in the absence (hatched bars) or presence of 200 μM (grey bars) or 400 μM (black bars) orthovanadate. Results are expressed as means±S.D. of duplicates for four independent experiments for CEM/VLB5 cells and for three independent experiments for CEM/VLB0.45 cells. (B) The reported P-gp ATPase activity is a result of the difference between activities measured in the presence and absence of 400 μM orthovanadate (bars). For each fraction, P-gp ATPase activity was normalized to total protein content of the fraction (secondary y axis and line). Results are expressed as means±S.D. of duplicates for four independent experiments (bars). One typical result from duplicate experiments is presented (line).