CHEMBL5735455

In Vitro Activity Assay: C-Raf TR refers to a truncated C-Raf protein, a Δ1-324 deletion mutant.C-Raf FL refers to the full-length C-Raf protein.Full length MEK1 with an inactivating K97R ATP binding site mutation is utilized as a RAF substrate. The MEK1 cDNA was subcloned with an N-terminal (his)6 tag into a vector for E. Coli expression. The MEK1 substrate was purified from E. Coli lysate by nickel affinity chromatography followed by anion exchange. The final MEK1 preparation was biotinylated (Pierce EZ-Link Sulfo-NHS-LC-Biotin) and concentrated.Assay MaterialsAssay buffer: 50 mM Tris, pH 7.5, 15 mM MgCl2, 0.01% Bovine Serum Albumin (BSA), 1 mM dithiothreitol (DTT)Stop buffer: 60 mM ethylenediaminetetraacetic acid (EDTA), 0.01% Tween® 20b-Raf(V600E), activebiotinylated Mek, kinase deadAlpha Screen detection kit (available from PerkinElmer™, #6760617R)Anti phospho-MEK1/2 (available from Cell Signaling Technology, Inc. #9121)384 well low volume assay plates (White Greiner® plates)Assay Conditionsb-Raf(V600E) approximately 4 μMc-Raf approximately 4 nMbiotinylated Mek, Kinase dead approximately 10 nMATP 10 μM for BRAF(V600E) and 1 uM for CRAFPre-incubation time with compounds 60 minutes at room temperatureReaction time 1 or 3 hours at room temperatureAssay ProtocolRaf and biotinylated Mek, kinase dead, were combined at 2× final concentrations in assay buffer (50 mM Tris, pH 7.5, 15 mM MgCl2, 0.01% BSA and 1 mM DTT) and dispensed 5 ml per well in assay plates (Greiner white 384 well assay plates #781207) containing 0.25 ml of 40× of a Raf kinase inhibitor test compound diluted in 100% DMSO. The plate was incubated for 60 minutes at room temperature.The Raf kinase activity reaction was started by the addition of 5 mL per well of 2×ATP diluted in assay buffer. After 3 hours (b-Raf(V600E)) or 1 hour (c-Raf). The reactions were stopped and the phosphorylated product was measured using a rabbit anti-p-MEK (Cell Signaling, #9121) antibody and the Alpha Screen IgG (ProteinA) detection Kit (PerkinElmer #6760617R), by the addition of 10 mL to the well of a mixture of the antibody (1:2000 dilution) and detection beads (1:2000 dilution of both beads) in Stop/bead buffer (25 mM EDTA, 50 mM Tris, pH 7.5, 0.01% Tween20). The additions were carried out under dark conditions to protect the detection beads from light. A lid was placed on top of the plate and incubated for 1 hour at room temperature, then the luminescence was read on a PerkinElmer Envision instrument. The concentration of each compound for 50% inhibition (IC50) was calculated b