CHEMBL3887764

Fluorescence Polarization Competition Immunoassay: A fluorescence polarization competition immunoassay was used to measure compound inhibition of CSF-1R phosphorylation of tyrosine on a synthetic CSF-1R555-568 peptide (SYEGNSYTFIDPTQ). The assay was performed in black 96-well microplates (Cat #42-000-0117, Molecular Devices, Sunnyvale, Calif.). To each well, 5 uL of compound (in 4% DMSO) were mixed with 2 uL of 3.5 nM CSF-1R, 25 mM MgCl2 in assay buffer (100 mM HEPES (hydroxyethylpiperazineethylsodiumsulfonate), pH 7.5, 1 mM DTT (dithiothreitol), 0.01% Tween-20), and 2 uL of 1540 uM peptide in assay buffer. The kinase reaction was initiated by adding 1 μL of 10 mM ATP in assay buffer. The final concentrations in the 10 uL reaction mixture were 100 mM HEPES, pH 7.5, 1 mM DTT, 0.01% Tween-20, 2% DMSO, 308 uM SYEGNSYTFIDPTQ, 1 mM ATP, 5 mM MgCl2, and 0.7 nM CSF-1R. Positive and negative control wells were included on each plate, where 4% DMSO in assay buffer was substituted for the compound; in addition, positive control wells received 1.2 uL of 50 mM EDTA (ethylenediaminetetraacetic acid) before the start of the reaction.