Inhibition of 1.5 μM [14C]2′-deoxyadenosine uptake into oocytes expressing PfENT4 (black circles), PvENT4 (gray triangles), or H2O-injected oocytes (white squares) with (A, B) isopentenyl adenine, (C, D)
trans-zeatin, or (E, F)
cis-zeatin. Each point in panels A, C, and E are the mean ± SD uptake of four oocytes from one experiment. Each point in panels B, D, and F are background-subtracted mean ± SD uptake into oocytes expressing PfENT4 and PvENT4 normalized to a % of uptake in the absence of unlabeled competitor. Data are fit with a single-site competition curve and IC50 values determined (see table 1).