CHEMBL5732058

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-R132H 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) containing 5 μM NADPH and 37.5 μM NADP; 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 60 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: IDH1-R132C homodimer enzyme is diluted to 0.1875 μg/ml in 40 μl of Assay Buffer (50 mM potassium phosphate, pH 6.5; 40 mM sodium carbonate, 5 mM MgCl2, 10% glycerol, 2 mM b-mercaptoethanol, and 0.03% BSA) containing 5 uM NADPH and 28.75 uM NADP. The concentration of alpha-ketoglutarate in the Substrate Buffer is 1 mM.