FIG. 3.

(A) Accumulation of [¹⁴C]pantothenate into isolated P. falciparum trophozoites in the presence (open circles) or absence (closed circles) of 1 mM pantothenol. [[¹⁴C]Pantothenate]_i/[[¹⁴C]Pantothenate]_o is the ratio of the concentration of [¹⁴C]pantothenate inside the parasite to that in the extracellular medium. (B) H⁺-coupled transport of [¹⁴C]pantothenate across the parasite plasma membrane in the presence or absence of 1 mM pantothenol or 0.2 mM phloretin. (C) Effect of pantothenol on the rate of phosphorylation of [¹⁴C]pantothenate in a parasite lysate. The dashed line in panel C represents the dose-response curve for the effect of pantothenol on [³H]hypoxanthine incorporation by the parasite (averaged from Fig. 2C). Complete inhibition of pantothenate phosphorylation in the lysate coincided with full inhibition of [³H]hypoxanthine incorporation. The data in panels A and B are averaged from two independent experiments (error bars represent the range divided by 2), and those in panel C are averaged from three experiments (error bars represent SEM). Where not shown, error bars fall within the symbols.