CHEMBL3887109

Inhibition Assay: Recombinant BACE-2 (extracellular domain, expressed in baculovirus and purified using standard methods) at 0.1 to 1 nM concentrations is incubated with the test compound at various concentrations for 1 hour at room temperature in 100 mM acetate buffer, pH 4.5, containing 0.1% CHAPS. Activity was measured using a final concentration of 3 μM of the fluorescence-quenched substrate Q-C(HSO3)-Ile-Asp-Leu-Ala-Val-Leu-Asp-HN-CH2-CH2-Mca, where Q=2-nitro-5-amino benzoic acid and Mca=7-methoxy-4-coumarinyl acetic acid. Catalytic turnover was monitored in a Spectramax Gemini fluorescence plate reader (Molecular Devices) in black 96-well microplates using excitation/emission wavelength of 325 nm and 400 nm, respectively. Fluorescence increase was followed for 15 min, in 1 minute's intervals. The fluorescence/time slopes were calculated from duplicate wells and from wells without inhibitor and the IC50 values were calculated using a logistic 4-parameter model.