CHEMBL5737599

Enzymatic Activity Assay: The inhibitory activity of the present compounds against Btk was assessed in a biochemical enzyme assay. Assay plates in 384 well format were prepared with 8-point serial dilutions for the test compounds on a Thermo CatX workstation equipped with a Innovadyne Nanodrop Express. The assay plates were prepared by addition of 50 nl per well of compound solution in 90% DMSO. The kinase reactions were started by stepwise addition of 4.5 μl per well of peptide/ATP-solution (4 μM FITC-Ahx-TSELKKVVALYDYMPMNAND-NH2, 164 μM ATP) in kinase buffer (50 mM HEPES, pH 7.5, 1 mM DTT, 0.02% Tween20, 0.02% BSA, 0.6% DMSO, 10 mM beta-glycerophosphate, and 10 μM sodium orthovanadate, 18 mM MgCl2, 1 mM MnCl2) and 4.5 μl per well of enzyme solution (6.4 nM full-length human recombinant BTK) in kinase buffer. Kinase reactions were incubated at 30° C. for 60 minutes and subsequently terminated by addition of 16 μl per well of stop solution (100 mM HEPES pH 7.5, 5% DMSO, 0.1% Caliper coating reagent, 10 mM EDTA, and 0.015% Brij35). Kinase reactions were analyzed on a Caliper LC3000 workstation by separating phosphorylated and unphosphorylated peptides and kinase activities were calculated from the amounts of newly formed phospho-peptide. Inhibition data were calculated by comparison to control reactions without enzyme (100% inhibition) and without inhibitors (0% inhibition).