Biochemical and molecular characterization of the pyrimidine biosynthetic enzyme dihydroorotate dehydrogenase from Toxoplasma gondii

► A recombinant Toxoplasma gondii dihydroorotate dehydrogenase (TgDHOD) was kinetically characterized. ► TgDHOD was not significantly affected by known inhibitors of human DHOD. ► Three Plasmodium falciparum DHOD inhibitors were tested and exhibited one to two orders of magnitude higher IC50s for TgDHOD. ► C-terminally tagged TgDHODs in transgenic T. gondii colocalize with the parasite's mitochondrion. ► Gene targeting suggested an essential role for TgDHOD that was not rescued by uracil supplementation.