CHEMBL5735926

Enzymatic Activity Assay of DPP-4: Human DPP-4 ((39-766)-His) and mouse DPP-4 ((29-760)-His) are purified by gel chromatography for use in the assay. The final concentration of hDPP-4 and mDPP-4 in the assay is 0.04 nM and 0.22 nM respectively.Inhibition of the catalytic activity of human and mouse DPP-4 by the compound in the present invention is monitored by the formation of product fluorescence AMC from substrate Gly-Pro-AMC (Sigma, G2761) on an Envision plate reader. The reaction is typically conducted by incubating the enzyme, test compound, and substrate (10 μM) in an assay buffer (75 μl) (0.01% BSA, 0.1 mM EDTA, 50 μM Tris-HCl, 0.01% Triton™-X100, 0.1 M NaCl at pH 7.5) for 30 minutes. After the reaction is stopped by the addition of ZnSO4 (25 μl, 10 mM), the formation of fluorescent product AMC is measured on an Envision plate reader with the excitation wavelength at 355 nm and emission wavelength at 460 nm. The IC50 value is calculated typically from a 10-point dose titration curve using the 4-parameter logistic equation.