CHEMBL5734873

Raf IC50 Assay Protocol: Compounds disclosed herein were tested against B-Raf (V600E) (PV3849, from Invitrogen) or C-Raf (Y340D/Y341D) (PV3805, from Invitrogen) in a time-resolved fluorescence energy transfer assay. The assay was carried out in reactions (10 μL) containing 0.0625 nM B-Raf or 0.5 nM C-Raf, 25 mM Tris pH 7.4, 10 mM MgCl2, 0.5 mM EGTA, 0.5 mM Na3BO4, 5 mM beta-glycerophosphate, 0.01%Triton X-100, 2.5 mM DTT, 0.1% BSA, 0.1 mM ATP, 13.7 nM GST-tagged MEK1 (Full-length protein with K97R mutation, recombinant protein purified from bacterial expression system) and 0-5 μM compounds disclosed herein (final concentration of 1% DMSO). The enzyme was incubated with the compounds at room temperature for 60 minutes and the reactions were initiated by the addition of ATP and GST-MEK1. After incubating at room temperature for 60 minutes, an equal volume of stop buffer containing 25 mM Tris pH 7.4, 400 mM KF, 50 mM EDTA, 0.01% BSA, 0.01% Triton X-100, 1 test of Eu3+ Cryptate-conjugated rabbit polyclonal antibody anti-Phospho MEK1/2 (Ser217/221) and 1 test of d2-conjugated mouse monoclonal antibody anti-glutathione S-transferase was added to stop the reactions. Plates were sealed and incubated at room temperature for 2 hours, and then the TR-FRET signals were read on BMG PHERAstar FS instrument. The IC50 for each compound was calculated by non linear regression by Graphpad Prism software.