CHEMBL5736396

Assay for Determination of KI Values for Inhibition of O-GlcNAcase Activity : Experimental procedure for kinetic analyses: Enzymatic reactions were carried out in a reaction containing 50 mM NaH2PO4, 100 mM NaCl and 0.1% BSA (pH 7.0) using 2 mM 4-Methylumbelliferyl N-acetyl-β-D-glucosaminide dihydrate (Sigma M2133) dissolved in ddH2O, as a substrate. The amount of purified human O-GlcNAcase enzyme used in the reaction was 0.7 nM. Test compound of varying concentrations was added to the enzyme prior to initiation of the reaction. The reaction was performed at room temperature in a 96-well plate and was initiated with the addition of substrate. The production of fluorescent product was measured every 60 sec for 45 min with a Tecan Infinite M200 plate-reader with excitation at 355 nM and emission detected at 460 nM, with 4-Methylumbelliferone (Sigma M1381) used to produce a standard curve. The slope of product production was determined for each concentration of compound tested and plotted, using standard curve fitting algorithms for sigmoidal dose response curves. The values for a four parameter logistic curve fit of the data were determined. KI values were determined using the Cheng-Prusoff equation; the Km of O-GlcNAcase for substrate was 0.2 mM. Many compounds of the invention exhibit KI values for inhibition of O-GlcNAcase in the range 0.1 nM-10 μM. The KI values for the compounds of the examples are shown in the table below. The following table shows representative data for the compounds of the Examples as determined by the assay described herein.