Tight-binding inhibitors efficiently inactivate both reaction centers of monomeric Plasmodium falciparum glyoxalase 1

Glucose consumption and therefore methylglyoxal production of human erythrocytes increase significantly upon infection with malaria parasites. The glyoxalase systems of the host-parasite unit cope with this metabolic challenge by catalyzing the removal of harmful methylglyoxal. Thus, glyoxalase 1 from the malaria parasite Plasmodium falciparum (PfGlo1) could be a promising drug target. However, the enzyme has two different active sites and their simultaneous inactivation is considered challenging. Here, we describe the inactivation of PfGlo1 by two glyoxalase-specific tight-binding inhibitors with nanomolar K _i ^app values and noncompetitive inhibition patterns. The inhibitors do not discriminate between the high-affinity and the high-activity conformations of PfGlo1, but seem to stabilize or trigger a conformational change in analogy with the substrate. In summary, we have characterized the most potent inhibitors of PfGlo1 known to date.