Eadie-Hofstee plots of low concentrations of estrone-3-sulfate uptake by OATP1B1 and its mutants.

<p><b>A</b>. Uptake of OATP1B1, <b>B</b>.D70N, <b>C</b>. F73Y and <b>D</b>. E74D. Uptake of E-3-S was measured at concentrations range from 0.01 to 1 µM. Uptake was conducted at 37°C for 2 min with empty vector, OATP1B1 or its mutants in HEK293 cells. Net uptake was obtained by subtracting the uptake of cells transfected with empty vector from cells expressing wild-type OATP1B1 or its mutants. Uptake of mutants was normalized to transporter expression at the cell surface in the same batch of cells and quantified relative to that of the wild-type. The results shown are means ± S.E. (<i>n</i> = 3).