Assay Method Information

Assay Name:  CDK6/CyclinD1 Enzymatic Activity Assay
Description:  The inhibitory activity of compounds was evaluated in vitro using TR-FRET assay with white 384-well low volume microplate (Greiner Bio-One). CDK6/Cyclin D1 catalyzed phosphorylation of peptide in the presence and absence of compounds was measured and used in IC50 determination. Recombinant protein complex CDK6/Cyclin D1, expressed from insect cell, was purchased from ProQinase. Testing compounds were dissolved in DMSO at 0.1 mM and tested in 9-dose IC50 mode. The reaction mixture was prepared by mixing CDK6/Cyclin D1 (1 nM final), ULight-4E-BP1 (100 nM final, Perkinelmer, TRF0128-D), and ATP (250 μM final) in assay buffer (20 mM of HEPES pH 7.4, 1 mM of EGTA, 0.05% BSA, 0.005% Tween 20, and 1 mM TCEP). The compound of interest in DMSO was added to each well in 3-fold serial dilution by dispenser (TECAN D300E). After 20 minutes preincubation at room temperature, 0.1 μL MgCl2 (10 mM final) was added to initiate the reaction. Following a 60 minutes incubation at 37° C., the reaction was stopped by addition of 2 μL of quenching buffer consisting of Lance detection buffer (Perkinelmer CR97-100C), 2 nM LANCE Ultra Europium-anti-P-4E-BP1 (Perkinelmer, TRF0216-D), 10 mM EDTA, and incubate at room temperature for additional 60 minutes in dark. The reaction signal was measured by Envision multimode plate reader (PerkinElmer, 2102-0010). IC50 values were determined by fitting the data to the standard 4 parameters with Hill Slope using GraphPad Prism software. Table 1, below, shows the IC50 values determined by this assay.
Affinity data for this assay
 

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