Figure 4

ATP-dependent transport of TCA, CA and GCA in membrane vesicles (7.5 μg protein) expressing BSEP/Bsep of human (▲), dogs (□), and cats (○). Vesicles were incubated in 10 mMTris Base buffer (pH 7.4) containing 250 mM Sucrose, 10 mM MgCl₂ and 4 mM ATP or AMP, at 37°C for 5 min (TCA) or 7.5 min (CA and GCA). ATP-dependent transport was calculated by subtracting transport in presence of AMP from that in presence of ATP. Curves were fitted by GraphPad Prism 6.01 software (San Diego, California, USA) and V_max was calculated. Measurements were performed in duplicate in at least three independent experiments. The mean of the duplicates of each experiment was transformed as a relative activity to the V_max (=100%). Each value in the graph is the mean ± SD of the relative activities of three independent experiments.