CHEMBL5733488

Human EGFR LanthaScreen Selectivity Assay: TR-FRET LanthaScreen assays were performed by incubating a dilution series of inhibitor concentrations with 20 μM ATP, 100 nM peptide substrate (FITC-C6-KKAEEEEYFELVAKK-NH2 (SEQ ID NO.: 2, American Peptide, #333778) and 600 μM of human EGFR kinase domain (Invitrogen). The assays were performed with and without pre-incubating the inhibitors with the enzyme for 60 minutes before starting the kinase reaction by adding ATP and the peptide substrate. Samples containing enzyme but no inhibitor were included to determine the maximal extent of reaction. Samples containing no enzyme served as the negative control. The kinase reaction mixtures were incubated at room temperature for 60 minutes before stopping the kinase activity by the addition of 15 mM EDTA. The extent of peptide phosphorylation by EGFR was detected using a Terbium-conjugated anti-phospho-Tyrosine antibody (Tb-PT66 antibody, invitrogen # PV3557). Phosphorylation of peptide substrate was measured by determining the ratio of 520/495 nm on an Envision Multi-label Reader (Perkin Elmer) and IC50 values were calculated by fitting the data to a four-parameter equation using XLFIt4 (IDBS).