CHEMBL3887164

Inhibiton Assay: IC50 values were determined for CB29 and its analogs using propionaldehyde as the substrate for ALDH1A1 and ALDH2 or benzaldehyde as the substrate for ALDH3A1. The assays were performed on a Beckman DU-640 spectrophotometer at various concentrations of inhibitors ranging from 50 nM to 250 μM following a 1 minute pre-incubation. There was no pre-incubation time-dependence to the inhibition. All reactions were initiated by the addition of the aldehyde substrate. The inhibition curves were fit to the Logistic four parameter IC50 equation using the SigmaPlot (v11, StatSys). We characterized the mode of inhibition using steady-state kinetics through co-variation of inhibitor and substrate concentrations. The steady state kinetic measurements were performed in 100 mM Na2HPO4 buffer, pH 7.5. The reaction mixture contained 10 nM ALDH3A1, varied benzaldehyde (50 μM-800 μM; fixed NADP+, 1.5 mM) and varied inhibitor concentrations. In all cases−including the control reactions lacking inhibitors, the final reaction mixture contained 2% (v/v) DMSO. The reaction was initiated by addition of substrate and the initial rate of product formation was determined on a Beckman DU-640.