CHEMBL5731765

Nrf2-Keap1 FP Assay #1: 100 nL of 100× compound dose response curves (serial 3-fold dilutions) in DMSO are stamped using an Echo liquid handling system (Labcyte) into 384-well low volume black assay plates (Greiner, #784076), with DMSO in columns 6 and 18. The top concentration of compound is located in columns 1 and 13. Keap1 (321-609) is diluted to 40 nM (2×) in 1× assay buffer (50 mM Tris, pH 8.0, 100 mM NaCl, 5 mM MgCl2, 1 mM DTT, 2 mM CHAPS, and 0.005% BSA) and 5 ul is added using a Multidrop Combi (Thermo Electron Corporation) equipped with a metal tip dispenser to all wells of the compound plate, except column 18. Column 18 receives only 5 ul of assay buffer. Immediately, 5 μL of 16 nM (2×) of Tamra labeled peptide (AFFAQLQLDEETGEFL, 21st Century Biochemicals) is added to all wells of the plate. The plates are spun at 500 rpm for 1 min, incubated for 1 h at room temperature, and read on an Analyst GT (Molecular Devices) equipped with excitation (530/25 nm) and emission (580/10 nm) filters designed for Tamra probes. A 561 nm dichroic mirror is also used in the Analyst. The final assay concentrations of Keap1 (321-609) and Tamra labeled peptide are 20 nM and 8 nM, respectively. Fluorescence measurements, represented as mP, are used in the transformation of the data. Compound activity is calculated based on percent inhibition, normalized against controls in the assay (Control 1 contains the Tamra peptide and Keap1 (321-609) together (0% response) and control 2 contains the Tamra peptide alone (100% response)). Data analysis is handled using the software package Abase XE (Surrey, United Kingdom.