CHEMBL5737044

Inhibitory Test of TNAP Activity: COS1 cells (DS Pharma Biomedical Co., Ltd.) were transfected with human TNAP (OriGene Technologies, Inc.) using Lipofectamine LTX & Plus reagent (Invitrogen Corp.). On the next day, the medium was replaced with a fresh medium, and the cells were cultured in an incubator for 3 days. After 3 days, the culture supernatant was collected and concentrated by centrifugation at 5000 G for 30 minutes using Amicon 14, 104 cut (Merck Millipore). The concentrated culture supernatant was dialyzed against 5 L of 50 mM Tris/200 mM NaCl/1 mM MgCl2/20 μM ZnCl2 twice and used as an enzyme source (enzyme solution). The substrate pNPP (ProteoChem Inc.) was adjusted to 3.1 mM with Milli-Q water, and a solution of each test compound dissolved in dimethyl sulfoxide (DMSO; Wako Pure Chemical Industries, Ltd.) by 6 serial dilutions at a 5-fold common ratio from 100 μM, or DMSO was added thereto at a final concentration of 1% by volume. The enzyme solution adjusted to 2 μg/mL with an assay buffer (200 mM Tris/2 mM MgCl2/0.04 mM ZnCl2/0.01% Tween 20) was added in the same amount of the substrate solution and incubated at room temperature for 60 minutes. Then, the absorbance (ABS: 405 nm) was measured using a microplate reader (model plus 384, Molecular Devices, LLC), and the concentration of produced p-nitrophenol was calculated. The inhibition of human TNAP activity by the test compound was evaluated on the basis of the concentration IC50 at which each test compound suppressed 50% of p-nitrophenol production.