Figure 4.

Characterization of [³H]adenosine and [³H]uridine uptake by yeast cells expressing OsENT2. [³H]adenosine uptake was examined in BY4735 ade2 cells expressing OsENT2 (A), whereas [³H]uridine uptake was tested in the yeast mutant ΔFUI1 expressing OsENT2 (B). Cells were incubated for 2 min at the indicated substrate concentrations at pH 6.0. Background uptake rates (empty vector pYES2) were subtracted. Affinity constants were calculated on the basis of Eadie-Hofstee plots (insets). Data shown are means ± se (n = 3).