CHEMBL5737549

In Vitro Kinase Inhibition Assay: CDK4 and CDK6: IC50 values of compounds against CDK4 and CDK6 were determined by luminescence using retinoblastoma as substrate. Kinase assays were performed in kinase buffer (#PV6135, Invitrogen, Life Technologies Grand Island, N.Y.) where total reaction volume was 30 μL/well in 96-well half area white plates (#3693, Costar). One microliter of 25× test compounds at specific concentrations (e.g., final concentration range: 0.1 nM-200 nM) were mixed with 10 μL of 2.5× kinase (5 nM, CDK4 #PR8064A and CDK6 #PR8422B, Invitrogen) solution and 14 μL of 4× mixed solution with retinoblastoma (1 μM, #12-439, EMD Millipore, Haywood, Calif.) and ATP (25 μM, #V7038, Promega, Madison, Wis.). The plates were covered and incubated for 2 h at room temperature. At the end of incubation, 25 μL of stop solution-ADP Glo reagent (#V7002, Promega) was added. After incubation for 45 min at room temperature, 50 μL of detection reagent (##V7002, Promega) was added. Readings were taken at 15 min and 45 min incubation after detection reagent was added in a Synergy Neo Plate reader (BioTek, Winooski) at single excitation of 340 nm and Dual emission at 495 nm and 520 nm respectively.