Figure 3.

The P. falciparum folate biosynthesis pathway. Enzymes inhibited by the antifolate drugs are shown. Point mutations in the dhps and dhfr mediate resistance to sulfa drugs and DHFR inhibitors, respectively. Increased copy number of the gch1 gene has been detected in clinical isolates from Southeast Asia and likely represents an adaptive evolutionary response to antifolate pressure [95]. Other abbreviations: pyruvoyltetrahydropterin synthase (ptps), hydroxymethyldihydropterin pyrophospholkinase (pppk) and dihydrofolate synthase (dhfs). Adapted from [94].