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.