Fig. 11
Haem fractionation profiles for atovaquone. Increase in percentage ‘free’ haem (a) and decrease in percentage Hz (b) seen with increasing Atov concentration. The total haem Fe (fg) per trophozoite of Atov-treated cells is statistically different to untreated cells (c). Graphs d and e show the amount of ‘free’ haem Fe (fg/cell) and Hz Fe per trophozoite respectively with increasing Atov concentration. The parasite survival curve for Atov overlaid with the percentage of ‘free’ haem (grey graph with open triangles, right axis) shows an apparent rise in ‘free’ haem with increasing Atov concentration correlated to parasite survival (f). However, by contrast to Hz inhibitors CQ and AQ, no relationship in fact exists between parasite survival and the actual amount of ‘free’ haem Fe (fg/cell) per trophozoite (black dashed graph with closed squares, right axis) which remains constant at 5.4 ± 0.4 fg haem Fe per cell. Atov IC50 as determined in D10 = 2.0 ± 0.8 nM