Inhibitors of Class II fructose 1,6‐bisphosphate aldolase

Fructose 1,6‐bisphosphate (FBP) aldolase (E.C. 4.1.2.13) catalyzes the reversible aldol condensation of dihydroxyacetonephosphate and glyceraldehyde 3‐phosphate in the Calvin cycle, glycolysis and gluconeogenesis. The FBP aldolases are divided in two groups depending on the reaction mechanism: Class I aldolases form a Schiff‐base intermediate with the substrate and Class II aldolases instead use a divalent metal to stabilize the carbanion intermediate. Since the Class II aldolase is not present in animals or plants, it has been suggested that it could be a viable drug target. In order to develop new specific inhibitors against these enzymes, the Class II FBP aldolases from Mycobacterium tuberculosis, Pseudomonas aeruginosa, Helicobacter pylori, Bacillus cereus and Magnaporthe grisea were cloned into the E. coli expression vector pT7‐7, purified and characterized. All enzymes are dimers except for the M. tuberculosis tetrameric aldolase. The enzymes’ pH curve, temperature and organic solvent stability, and metal utilization were measured. Derivatives of the metal binding agent 2,6‐pyridinedicarboxylic acid, designed to resemble FBP, were synthesized and found to behave as specific mixed inhibitors of the Class II enzyme aldol cleavage reaction. This work was supported by grants from the Natural Sciences and Engineering Research Council of Canada. * Recipient of an Ontario Graduate Scholarship.