CHEMBL3707974

Enzyme Assay: Test article and assay controls were added to a 384-well plate. Reaction mixtures contained 20 mM HEPES, pH 7.4, 10 mM magnesium chloride, 0.01% bovine serum albumin (BSA), 0.0005% Tween 20, 1 mM ATP and 1 μM peptide substrate. The JAK1 and TYK2 assays contained 1 μM of the IRStide peptide (5FAMKKSRGDYMTMQID) and the JAK2 and JAK3 assays contained 1 μM of the JAKtide peptide (FITC-KGGEEEEYFELVKK). The assays were initiated by the addition of 20 nM JAK1, 1 nM JAK2, 1 nM JAK3 or 1 nM TYK2 enzyme and were incubated at room temperature for three hours for JAK1, 60 minutes for JAK2, 75 minutes for JAK3 or 135 minutes for TYK2. Enzyme concentrations and incubation times were optimized for each new enzyme preps and were modified slightly over time to ensure 20%-30% phosphorylation. The assays were stopped with a final concentration of 10 mM EDTA, 0.1% Coating Reagent and 100 mM HEPES, pH=7.4.