Figure 3: Michaelis-Menten kinetics of PAH transport in CHO-mOat1 cells. In order to calculate values for mOat1, the value for PAH needed to be determined in the CHO-mOat1 cell system. Uptake of [3H]PAH was measured for 2 min at room temperature in CHO-mOat1 (closed triangles) and CHO-FRT (open squares) cells in order to construct a saturation curve. The corrected curve (closed circles) was obtained by subtracting the nonspecific background uptake as measured in the CHO-FRT cells from CHO-mOat1 accumulation to allow analysis of mOat1-mediated activity. Experiments were repeated three times in triplicate, and Michaelis constant ( ) values were calculated by nonlinear regression using the Michaelis-Menten model. The for PAH on mOat1 was estimated as μM (mean ± S.E.M.). Graph shown is from a representative experiment with values plotted as mean ± S.D. ( ).