CHEMBL5732054

In Vitro Assays for IDH1m (R132H or R132C) Inhibitors: A test compound is prepared as 10 mM stock in DMSO and diluted to 50× final concentration in DMSO, for a 50 μl reaction mixture. IDH enzyme activity converting alpha-ketoglutarate to 2-hydroxyglutaric acid is measured using a NADPH depletion assay. In the assay the remaining cofactor is measured at the end of the reaction with the addition of a catalytic excess of diaphorase and resazurin, to generate a fluorescent signal in proportion to the amount of NADPH remaining. IDH1-R132 homodimer enzyme is diluted to 0.125 μg/ml in 40 μl of Assay Buffer (150 mM NaCl, 20 mM Tris-Cl pH 7.5, 10 mM MgCl2, 0.05% BSA, 2 mM b-mercaptoethanol); 1 μl of test compound dilution in DMSO is added and the mixture is incubated for 60 minutes at room temperature. The reaction is started with the addition of 10 μl of Substrate Mix (20 μl NADPH, 5 mM alpha-ketoglutarate, in Assay Buffer) and the mixture is incubated for 90 minutes at room temperature. The reaction is terminated with the addition of 25 μl of Detection Buffer (36 μg/ml diaphorase, 30 mM resazurin, in 1× Assay Buffer), and is incubated for 1 minute before reading on a SpectraMax platereader at Ex544/Em590.Compounds are assayed for their activity against IDH1 R132C following the same assay as above with the following modifications: Assay Buffer is (50 mM potassium phosphate, pH 6.5; 40 mM sodium carbonate, 5 mM MgCl2, 10% glycerol, 2 mM b-mercaptoethanol, and 0.03% BSA). The concentration of NADPH and alpha-ketoglutarate in the Substrate Buffer is 20 μM and 1 mM, respectively.