| Assay Method Information | |
| | TR-FRET (Time-Resolved Fluorescence Resonance Energy Transfer) Assay |
| Description: | In this assay, the potency (IC50) of each compound was determined from a ten point (1:3 serial dilution; final compound concentration range in assay from 100000 nM to 5.08 nM) titration curve using the following outlined procedure. To each well of a white Greiner 1536 Lumitrac 1536 well-plate, 50 nL of compound (100 fold dilution in final assay volume of 5 μL) was dispensed, followed by the addition of 4 μL of 1× assay buffer (50 mM Hepes 7.3, 0.5 mM TCEP, 0.005% Brij-35, 0.02% BSA, 50 μM Na-L-Ascorbate and 2 μM AmFe(II)Sulfate) containing 5 nM of Full-length KDM5B enzyme (recombinant protein from baculovirus-transfected Sf21 cells: full-length KDM5B; MW=176.825 kDa). Following a 30 minutes compound and enzyme incubation in a humidified chamber, each reaction was initiated by the addition of 1 μL 1× assay buffer containing 50 nM biotinylated H3K4Me3 peptide, and 500 nM α-ketoglutarate. The final reaction in each well of 5 μL consists of 5 nM KDM5B, 500 nM biotinylated-peptide, and 500 nM α-ketoglutarate. De-methylation reactions were allowed to proceed for 60 minutes. Reactions were immediately quenched by the addition of 5 uL of 2× Lance Detection Buffer (PerkinElmer) with 0.5 mM EDTA and 2 nM of Eu-anti-H3K4Me1-2 antibody, and 30 nM of Streptavidin-conjugated Dylight 650 detection reagents. After 60 minutes incubation with detection reagents, reaction plates were read on a PerkinElmer EnVision plate reader using standard TR-FRET protocol. Briefly, excitation of donor molecules (Eu-chelate-anti-H3K4Me1-2-antibody) with a laser light source at 337 nm produces energy that can be transferred to Dylight-650 acceptor molecules if this donor:acceptor pair is within close proximity. Fluorescence intensity at both 665 nm (acceptor) and 615 nm (donor) are measured and a TR-FRET ratio calculated for each well (acceptor intensity/donor intensity). |
| Affinity data for this assay | |
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