CHEMBL3705255

In Vitro Inhibition Assay: Measurements were performed in a reaction volume of 50 μL using 96-well assay plates. Kinase enzyme, inhibitor, ATP (at the Km for the kinase), and 1 μM peptide substrate (Biotin-AVLESEEELYSSARQ-NH2) were incubated in a reaction buffer composed of 20 mM Tris, 50 mM NaCl, MgCl2 (5-25 mM depending on the kinase), MnCl2 (0-10 mM), 1 mM DTT, 0.1 mM EDTA, 0.01% bovine serum albumin, 0.005% Tween-20, and 10% DMSO at pH 7.4 for one hour. The reaction was quenched by the addition of 1.2 equivalents of EDTA (relative to divalent cation) in 25 μL of 1× Lance buffer (Perkin-Elmer). Streptavidin-APC (Perkin-Elmer) and Eu-labeled p-Tyr100 antibody (Perkin-Elmer) in 1× Lance buffer were added in a 25 μL volume to give final concentrations of 100 nM and 2.5 nM, respectively, and the mixture was allowed to incubate for one hour. The TR-FRET signal was measured on a multimode plate reader with an excitation wavelength (πEx) of 330 nm and detection wavelengths (πEm) of 615 and 665 nm. Activity was determined by the ratio of the fluorescence at 665 nm to that at 615 nm. For each compound, enzyme activity was measured at various concentrations of compound. Negative control reactions were performed in the absence of inhibitor in replicates of six, and two no-enzyme controls were used to determine baseline fluorescence levels.