CHEMBL5735284

PDGFRbeta Kinase Assay: Biochemical PDGFRβ kinase assays were performed in 96 well microtiter plates that were coated overnight with 75 μg of poly-Glu-Tyr (4:1) in 10 mM Phosphate Buffered Saline (PBS), pH 7.4. The coated plates were washed with 2 mls per well PBS +0.05% Tween-20 (PBS-T), blocked by incubation with PBS containing 1% BSA, then washed with 2 mls per well PBS-T prior to starting the reaction. Reactions were carried out in 100 μL reaction volumes containing 36 μM ATP in kinase buffer (50 mM Hepes buffer pH 7.4, 20mM MgCl2, 0.1 mM MnCl2 and 0.2 mM Na3VO4). Test compounds were reconstituted in 100% DMSO and added to the reaction to give a final DMSO concentration of 5%. Reactions were initiated by the addition 20 ul per well of kinase buffer containing 200-300 ng purified cytoplasmic domain PDGFR-b protein (Millipore). Following a 60 minute incubation at 30° C., the reactions were washed 2 mls per well PBS-T. 100 μl of a monoclonal anti-phosphotyrosine antibody-peroxidase conjugate diluted 1:10,000 in PBS-T was added to the wells for 30 minutes. Following a 2 mls per well wash with PBS-Tween-20, 100 μl of O-Phenylenediamine Dihydrochloride in phosphate-citrate buffer, containing urea hydrogen peroxide, was added to the wells for 7-10 minutes as a colorimetric substrate for the peroxidase. The reaction was terminated by the addition of 100 μl of 2.5N H2SO4 to each well and read using a microplate ELISA reader set at 492 nm. IC50 values for compound inhibition were calculated directly from graphs of optical density (arbitrary units) versus compound concentration following subtraction of blank values.