CHEMBL5733157

Inhibition Assay: The kinase activity of purified human MAP4K4 kinase domain was measured by monitoring the phosphorylation of a peptide substrate derived from moesin protein (Leu-Gly-Arg-Asp-Lys-Tyr-Lys-Thr-Leu-Arg-Gln-Ile-Arg-Gln) fluorescently labeled on the N-terminus with 5-carboxyfluorescein using the Caliper LabChip technology (Caliper Life Sciences, Hopkinton, Mass.). To determine inhibition constants (IC50), compounds were serially diluted in DMSO and added to 10 uL kinase reactions containing 1 nM purified MAP4K4 enzyme, 1 uM peptide substrate, 10 uM ATP, 10 mM MgCl2, 1 mM EGTA, 50 mM Hepes pH 7.2, 1 mM DTT, 0.01% Triton X-100, and 2% DMSO. Reactions were incubated at room temperature in Perkin Elmer Proxiplates for 45 minutes and stopped by the addition of 10 uL of an EDTA-containing solution (50 mM Hepes pH 7.2, 40 mM EDTA, 0.02% Triton X-100). The fraction of phosphorylated peptide was determined as a fraction of total peptide substrate using the Caliper Lab Chip 3000 according to the manufacturer's instructions. IC50 values were determined using the four-parameter non-linear fit model.