| Assay Method Information | |
| | DNMT1 Enzyme Activity Assay |
| Description: | The biochemical assay to measure DNMT1 enzyme activity relies on time-resolved fluorescence energy transfer (TR-FRET) between lumi4-Tb (donor) and d2 (acceptor) using the EPlgeneous methyltransferase assay (CisBio Cat#62SAHPEB). TR-FRET is observed when antibody specific to S-adenosylhomocysteine labeled with Lumi4-Tb is incubated with d2-labeled S-adenosylhomocysteine. TR-FRET signal is inversely proportional to the concentration of SAH, product of DNMT1 enzyme activity, in the sample. The human DNMT1 was obtained from Reaction Biology Corp. (Cat# DMT-21-124).Enzyme activity assay was carried out in a white 384-well plate in a final volume of 20 μl, as follow: 4 μl of vehicle or studied compound 2.5× concentrated prepared in assay buffer (50 mM Tris-HCl, 1 mM EDTA, 1 mM DTT, 0.1% Triton X-100, 5% glycerol pH 7.5). Final percentage of DMSO was 0.5%. 2 μl of 1 nM DNMT1 enzyme diluted in assay buffer. Final concentration was 20 nM. Start the reaction by adding 4 μl of substrate mixture containing 1 μM S-adenosylmethionine and 1 μM poly-deoxy inosine poly-deoxy cytosine (pdI-pdC) DNA. Reaction was carried out during 15 minutes at 37° C. Enzyme activity was stopped by adding 2 μl of buffer one of the EPIgeneous methyltransferase assay. After 10 minutes at room temperature, it was added 4 μl of antibody specific to S-adenosylhomocysteine labeled with Lumi4-Tb 50× diluted in buffer two of the EPIgeneous methyltransferase assay. Add 4 μl of d2-labeled S-adenosylhomocysteine 31× diluted in buffer two of the EPIgeneous methyltransferase assay. Read the plate after 1 hour of incubation at room temperature.For each well, fluorescence was measured at 620 nm and 665 nm. A ratio (665 nm/620 nm) was then calculated in order to minimize medium interferences. Positive control was obtained in the presence of the vehicle of the compounds. Negative control was obtained in the absence of G9a enzyme activity. Calculated IC50 values were determined using GraphPrism using 4-parameters inhibition curve. |
| Affinity data for this assay | |
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