CHEMBL5733322

PHF8 Assay: PHF8 Assay: The ability of test compounds to inhibit the activity of PHF8 was determined in 384-well plate format under the following reaction conditions: 3 nM PHF8, 200 nM H3K9me1-biotin labeled peptide (Anaspec cat #64358), 0.5 uM alpha-ketoglutaric acid in assay buffer of 50 mM HEPES, pH7.3, 0.005% Brij35, 0.5 mM TCEP, 0.2 mg/ml BSA, 50 uM sodium L-ascorbate, and 5 uM ammonium iron(II) sulfate. Reaction product was determined quantitatively by TR-FRET after the addition of detection reagent Phycolink Streptavidin-allophycocyanin (Prozyme) and Europium-anti-unmodified-histone H3 lysine 9/lysine27 (H3K9/K27) antibody (PerkinElmer) in the presence of 5 mM EDTA in LANCE detection buffer (PerkinElmer) at a final concentration of 25 nM and 0.5 nM, respectively.The assay reaction was initiated by the following: 2 ul of the mixture of 600 nM H3K9me1-biotin labeled peptide and 1.5 uM alpha-ketoglutaric acid with 2 ul of 11-point serial diluted inhibitor in 3% DMSO were added to each well of the plate, followed by the addition of 2 ul of 9 nM PHF8 to initiate the reaction. The reaction mixture was incubated at room temperature for 15 minutes, and terminated by the addition of 6 ul of 5 mM EDTA in LANCE detection buffer containing 50 nM Phycolink Streptavidin-allophycocyanin and 1 nM Europium-anti-unmodified H3K9/K27 antibody. Plates were read by EnVision Multilabel Reader in TR-FRET mode (excitation at 320 nm, emission at 615 nm and 665 nm) after 1 hour incubation at room temperature. A ratio was calculated (665/615) for each well and fitted to determine inhibition constant (IC50).