FIG. 4.

Effect of starting concentration on the specific uptake of radiolabeled artemisone in mature infected erythrocytes over time. Cell samples were divided into supernatant and pellet fractions after lysis in Triton and deproteinization with TCA, with the data presented for the pellet fraction only. The specific uptake was calculated by subtracting the nonspecific uptake (defined as accumulation at 4°C in the presence of unlabeled artemisone) from the total uptake measured at 37°C. Data are corrected for 100% parasitemia. The initial radiolabeled artemisone concentrations used were 20 μM (triangles), 4 μM (squares), and 0.4 μM (inset) (circles). Data are derived from 3 or 4 independent experiments and are shown as means ± SEM.