CHEMBL5733697

Recombinant Enzyme Assay: Compounds were assessed for their ability to inhibit the enzymatic activity of a recombinant form of Glutaminase 1 (GAC) using a biochemical assay that couples the production of glutamate (liberated by GAC) to glutamate dehydrogenase (GDH) and measuring the change in absorbance for the reduction of NAD+ to NADH. Enzyme solution was prepared (50 mM Tris-HCl pH 8.0, 0.2 mM EDTA, 150 mM K2HPO4, 0.1 mg/ml BSA, 1 mM DTT, 10 ppm antifoam, 4 units/ml GDH, 4 mM adenosine diphosphate, and 4 nM GAC) and 50 μL added to a 96-well half area clear plate (Corning #3695). Compound (2 μL) was added to give a final DMSO concentration of 2% at 2× the desired concentration of compound. The enzyme/compound mix was sealed with sealing foil (USA Scientific) and allowed to incubate, with mild agitation, for 60 minutes at 20° C. Enzymatic reaction was started with the addition of 50 μL of substrate solution (50 mM Tris-HCl pH 8.0, 0.2 mM EDTA, 150 mM K2HPO4, 0.1 mg/ml BSA, 1 mM DTT, 20 mM L-glutamine, 2 mM NAD+, and 10 ppm antifoam) and read in a Molecular Devices M5 plate reader at 20° C. The plate reader was configured to read absorbance (λ=340 nm) in kinetic mode for 15 minutes. Data was recorded as milli-absorbance units per minute and slopes were compared to a control compound and a DMSO-only control on the same plate. Compounds with slopes less than the DMSO control were considered inhibitors and plate variability was assessed using the control compound.