Discovery of aldolase A inhibitors via high-throughput screening assay based on an enzymatic coupling reaction

Aldolase A (ALDOA) is a key enzyme in glycolysis, catalyzing the reversible conversion of fructose-1,6-diphosphate (FBP) to dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (GAP). The aberrant overexpression of ALDOA is associated with the development of various solid tumors. Here, we developed an in vitro enzymatic coupling reaction assay, which demonstrates high cost-efficiency and is suitable for high-throughput screening (HTS). With this assay we identified two potential ALDOA inhibitors, merbromin and ellagic acid, from our in-house compound library. Merbromin and ellagic acid exhibit significant inhibitory activities with IC₅₀ values of 8.49 ± 0.62 μM and 19.87 ± 2.03 μM, respectively. The nuclear magnetic resonance (NMR) and surface plasmon resonance (SPR) experiments further confirmed their high affinities to ALDOA, with the dissociation constants (K_d) of 0.49 ± 0.10 μM and 0.64 ± 0.10 μM, respectively. Enzyme kinetics experiment revealed that both compounds act as noncompetitive inhibitors of ALDOA. Our study showed that the enzymatic coupling reaction-based assay established here is highly effective and offers a promising approach for the development of ALDOA inhibitors.