CHEMBL5736605

Enzyme Inhibition Assay: Enzyme inhibition studies were performed using recombinant JAK1 (amino acids 866-1154, Life Technologies, #PV4774, Carlsbad, Calif.), JAK2 (amino acids 831-1132, AstraZeneca R&D Boston), or JAK3 (amino acids 781-1124, AstraZeneca R&D Boston) under buffer conditions of 50 mM HEPES pH 7.3, 1 mM DTT, 0.01% Tween-20, 50 μg/ml BSA, and 10 mM MgCl2. JAK enzyme was expressed as N-terminal GST fusion in insect cells and purified by glutathione-affinity and size-exclusion chromatographies. Enzymes were assayed at their approximated high end of physiological ATP concentration of 5 mM, in the presence of inhibitor dosed at 30, 3, 0.3, 0.03, 0.003 and 0 μM final test concentrations.For JAK1, 4 nM of enzyme was incubated with 1.5 μM peptide substrate (FITC-C6-KKHTDDGYMPMSPGVA-NH2 (SEQ ID NO:1), Intonation, Boston, Mass.). For JAK2, 0.3 nM enzyme was incubated with 1.5 μM peptide substrate (5FAM-GEEPLYWSFPAKKK-NH2 (SEQ ID NO:2), Intonation, Boston, Mass.), For JAK3, 0.1 nM enzyme was incubated with 1.5 μM peptide substrate (5FAM-GEEPLYWSFPAKKK-NII2 (SEQ ID NO:2), Intonation, Boston, Mass.). Phosphorylated and unphosphotylated peptides were separated and quantified by a Caliper LC3000 system (Caliper Life Sciences, MA) for calculating percent inhibition.