CHEMBL3887899

Kinase Assay (New): Compound potency against activated ERK2 is determined using a kinase assay that measures ERK2-catalyzed phosphorylation of biotinylated ERKtide peptide substrate ([Biotin]-AHA-K-R-E-L-V-E-P-L-T-P-S-G-E-A-P-N-Q-A-L-L-R-[NH2], the peptide sequence derived from EGF receptor: SEQ ID NO:1). The assay is carried out in 50 mM HEPES [pH 7.5], 5 mM MgCl2, 1 mM DTT, 0.01% Tween-20, 0.05% BSA using 0.25 nM ERK2, 200 nM ERKtide peptide and 35 uM ATP (all concentrations are final in the reaction) in a total volume of 10.25 uL. A 16-point, half-log dilution series of compounds at 41x final concentration is used for generating IC50 curves. Compound dilution series are prepared in 100% DMSO. ERK2 is preincubated with compounds for 30 minutes at ambient temperature. Reaction is initiated by addition of a substrate cocktail of ERKtide peptide and ATP and is allowed to proceed for 2-3 hours at ambient temperature. Reaction is terminated by addition of 10 uL of a 2x stop buffer consisting of 100 mM Tris-Cl [pH 7.5], 25 mM EDTA, 0.01% Tween 20, 10 ug/mL of AlphaScreen Protein A Acceptor Beads, 10 ug/mL of Streptavidin Donor Beads (PerkinElmer, Waltham, Mass.), and 1.4 ug/mL phospho-EGF Receptor (Thr669) antibody (Cat #3056, Cell Signaling Technology, Danvers, Mass.). Terminated reactions are read, after overnight incubation in the dark, on an EnVision Multilabel Plate Reader (PerkinElmer, Waltham, Mass.), with excitation and emission wavelengths set to 680 nm and 570 nm, respectively. IC50 values are determined using a four-parameter fit.