CHEMBL3887150

High Throughput Syk Biochemical Assay: Syk activity was measured using KinEASE (Cisbio), a time-resolved fluorescence resonance energy transfer (TR-FRET) immunoassay. In this assay, Syk-catalyzes the phosphorylation of a XL665-labeled peptide substrate. Europium conjugated phospho-tyrosine specific antibody binds the resulting phosphorylated peptide. Formation of phosphorylated peptide is quantified by TR-FRET with Europium as the donor and XL665 the acceptor in a 2-step endpoint assay. In brief, test compounds serially diluted in DMSO were delivered into Corning white, low volume, non-binding 384 well plates using the Echo 550 acoustic liquid dispenser (Labcyte®). Syk enzyme and substrates were dispensed into assay plates using a Multi-Flo (Bio-Tek Instruments). The standard 5 μL reaction mixture contained 20 μM ATP, 1 μM biotinylated peptide, 0.015 nM of Syk in reaction buffer (50 mM Hepes, pH 7.0, 0.02% NaN3, 0.1% BSA, 0.1 mM Orthovanadate, 5 mM MgCl2, 1 mM DTT, 0.025% NP-40). After 30 minutes of incubati