CHEMBL5737320

Caliper Enzyme Assay (4 mM ATP): JAK Caliper Enzyme Assay at 1 mM ATP: Test article was solubilized in dimethyl sulfoxide (DMSO) to a stock concentration of 30 mM. An 11-point half log dilution series was created in DMSO with a top concentration of 600 μM. The test compound plate also contained positive control wells containing a known inhibitor to define 100% inhibition and negative control wells containing DMSO to define no inhibition. The compound plates were diluted 1 to 60 resulting in a top final assay compound concentration of 10 μM and a 2% DMSO concentration.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, 4 μM or 1 mM ATP and 1 μM peptide substrate. The JAK3 assays contained 1 μM of the JAKtide peptide (FITC-KGGEEEEYFELVKK). The assays were initiated by the addition 1 nM JAK3 enzyme and were incubated at room temperature 75 minutes for JAK3. 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. The assay plates were placed on a Caliper Life Science Lab Chip 3000 (LC3000) instrument, and each well was sampled using appropriate separation conditions to measure the unphosphorylated and phosphorylated peptide.