| Assay Method Information | |
| | CDK12/CycK High ATP Kinase Assay |
| Description: | For the assay 50 nanoL of a 100 fold concentrated solution of the test compound in DMSO was pipetted into either a black low volume 384 well microtiter plate or a black 1536 well microtiter plate (both Greiner Bio-One, Frickenhausen, Germany), 2 microL of a solution of CDK12/CycK in aqueous assay buffer [25 millimol/L HEPES pH 7.5, 20 millimol/L MgCl2, 5 millimol/L β-glycerophosphate, 2 millimol/L EGTA, 1.0 millimol/L dithiothreitol, 0.01% (v/v) Nonidet-P40 (Sigma), 0.01% (w/v) bovine serum albumin] were added and the mixture was incubated for 15 min at 22° C. to allow pre-binding of the test compounds to the enzyme before the start of the kinase reaction. Then the kinase reaction was started by the addition of 3 microL of a solution ATP (3.33 millimol/L=>final conc. in the 5 microL assay volume is 2 millimol/L) and substrate (1.67 micromol/L=>final conc. in the 5 microL assay volume is 1 micromol/L) in assay buffer and the resulting mixture was incubated for a reaction time of 60 min at 22° C. The concentration of CDK12/CycK was adjusted depending of the activity of the enzyme lot and was chosen appropriate to have the assay in the linear range, typical concentrations were about 0.75 nanomol/L. The reaction was stopped by the addition of 3 microL of a solution of TR-FRET detection reagents (125 nanomol/L streptavidine-XL665 [Cisbio Bioassays, Codolet, France] and 0.67 nanomol/L anti-Phospho-c-Myc (Ser 62) (E1J4K)-antibody from Cell Signalling [#13748] and 2 nanomol/L LANCE EU-W1024 labeled anti-rabbit IgG antibody [Perkin-Elmer, product no. 0083]) in an aqueous EDTA-solution (133 millimol/L EDTA, 0.27% (w/v) bovine serum albumin in 66.7 millimol/L HEPES pH 7.5).The resulting mixture was incubated 1 h at 22° C. to allow the formation of complex between the phosphorylated biotinylated peptide and the detection reagents. Subsequently the amount of phosphorylated substrate was evaluated by measurement of the resonance energy transfer from the Eu-chelate to the streptavidine-XL. Therefore, the fluorescence emissions at 620 nm and 665 nm after excitation at 350 nm was measured in a TR-FRET reader, e.g. a Pherastar FS (BMG Labtechnologies, Offenburg, Germany) or a Viewlux (Perkin-Elmer). |
| Affinity data for this assay | |
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