Small molecule probes of glyoxalase I and glyoxalase II.

A number of synthetic tropolones and hydrophobic S-blocked glutathione analogues were investigated as potential inhibitors of glyoxalase I from Saccharomyces cerevisiae and glyoxalase II from bovine liver. Several tropolones containing a free C-2 hydroxy group were found to be potent inhibitors of glyoxalase I, whereas the glutathione conjugates were found to be modest to poor inhibitors of this enzyme. Most tropolones and glutathione conjugates, except 5-p-tolylazotropolone and S-carbobenzoxy-L-glutathione, were found to be poor inhibitors of glyoxalase II. A recent report on an extremely active glyoxalase system from Plasmodium falciparum suggested that several of the more potent inhibitors may have antimalarial properties. A number of these compounds in fact, exhibited antimalarial activity in the low micromolar range. Further studies are required to fully elucidate the mechanism(s) of the antimalarial properties of these compounds.