CHEMBL5734110

TAM Enzymatic Assay: The kinase assay buffer contained 50 mM HEPES, pH7.5, 10 mM MgCl2, 1 mM EGTA, 0.01% NP-40 and 2 mM DTT. 0.1 ul test compounds dissolved in DMSO were transferred from compound plates to white 384-well assay plates (Greiner LUMITRAC plates). The final concentration of DMSO was 1.25%. Enzyme solutions of 5.1 nM phosphor-Axl, or 0.0625 nM c-Mer (Carna Biosciences, 08-108), or 0.366 nM Tyro3 (Life Technologies, PR7480A) were prepared in assay buffer. A 1 mM stock solution of peptide substrate Biotin-EQEDEPEGDYFEWLE-amide SEQ ID NO:1 (Quality Controlled Biochemicals, MA) dissolved in DMSO was diluted to 1 uM in assay buffer containing 2000 uM ATP. 4 ul enzyme solution (or assay buffer for the enzyme blank) was added to the appropriate wells in each plate, and then 4 ul/well substrate solution was added to initiate the reaction. The plate was protected from light and incubated at room temperature for 60 min. The reaction was stopped by adding 4 ul detection solution containing 50 mM Tris-HCl, pH7.8, 150 mM NaCl, 0.05% BSA, 45 mM EDTA, 180 nM SA-APC (Perkin Elmer, CR130-100) and 3 nM Eu-W1024 anti-phosphotyrosine PY20 (Perkin Elmer, AD0067). The plate was incubated for 1 h at room temperature, and HTRF (homogenous time resolved fluorescence) signal was measured on a PHERAstar FS plate reader (BMG labtech). Percentage of inhibition was calculated for each concentration and IC50 value was generated from curve fitting with GraphPad Prism software.