Enzyme Inhibition Assay: The enzyme inhibition assays used monitored the ability of a test compound to bind and prevent the hydrolysis of a fluorogenic substrate in a concentration-dependent mariner. Specifically, the enzyme activity of recombinant human GCase (rhGCase; Cerezyme, Genzyme Corp.) was measured using the 4-methylumbelliferyl-β-D-glucopyranoside (4-MU-β-D-Glc) fluorogenic substrate in the absence or in the presence of varying amounts of each test compound.
Enzyme Assay: To 2.5 μl of supernatant (in 96-well plates) was added 17.5 μl reaction buffer (citrate phosphate buffer, pH 4.5, no Triton X-100), and 50 μl of 4-methyl umbelliferone (4-MU)-labeled substrate, β-glucopyranoside, or a labeled negative controls (α-glucopyranoside or α-galacatopyranoside). Plates were incubated at 37° for 1 hour, followed by the addition of 70 μl stop buffer (0.4 M glycine-NaOH, pH 10.6). Activity of GCase was determined by measuring the emission at 460 nm by exciting at 355 nm using a 1 second read time per well (Victor2 multilabel counter-Wallac) Enzyme activity was normalized to the amount in μl of lysate added, and enzyme activity per μl of lysate was estimated.
Enzyme Activity Assay: Activity of GBA was measured at 37° C. with 4-methylumbelliferyl β-D-glucopyranoside as substrate as reported previously. To determine the IC50 value, the inhibitors were preincubated for 30 min with the enzyme before addition of the substrate mixture. The incubation mixture contained 3 mM fluorogenic substrate, 0.2% (w/v) sodium taurocholate and 0.1% (v/v) Triton X-100 in 150 mM McIlvaine buffer, pH 5.2. After stopping the incubation with excess NaOH-glycine (pH 10.3), we measured fluorescence with a fluorimeter LS 30 (Perkin Elmer) using λex 366 nm and λem 445 nm. Activity of lactase was quantified by measuring liberated glucose from lactase38. In vivo activity of GBA in cells was measured using FDG as substrate and FACS32.
Inhibition of human beta-glucosidase isolated from human fibroblasts incubated for 30 mins using 4-methylumbelliferone -conugated beta-D-galactoside as substrate by fluorescence analysis
Pharmacological chaperone activity at beta-glucocerebrosidase N370S mutant in Gaucher disease patient-derived lymphoblasts with GCase N370S mutant assessed as increase in enzyme activity at 2.5 uM after 3 days by fluorimetric analysis relative to control
Pharmacological chaperone activity at beta-glucocerebrosidase L444P mutant in Gaucher disease patient-derived lymphoblasts expressing with GCase L444P mutant assessed as increase in enzyme activity at 5 uM after 3 days by fluorimetric analysis relative to control
Pharmacological chaperone activity at beta-glucocerebrosidase N370S mutant in Gaucher disease patient-derived lymphoblasts with GCase N370S mutant assessed as increase in enzyme activity at 10 uM after 3 days by fluorimetric analysis relative to control
Competitive inhibition of human recombinant imiglucerase using 4-MU-beta-D-Glu as substrate at pH 5.2 after 30 mins by fluorometry based Lineweaver-Burk plot analysis
Pharmacological chaperone activity at beta-glucocerebrosidase N370S mutant in Gaucher disease patient-derived lymphoblasts with GCase N370S mutant assessed as increase in enzyme activity at 3.125 to 100 uM after 3 days by fluorimetric analysis relative to control
Pharmacological chaperone activity at beta-glucocerebrosidase N370S mutant in Gaucher disease patient-derived lymphoblasts with GCase N370S mutant assessed as increase in enzyme activity at 12.5 uM after 3 days by fluorimetric analysis relative to control
Pharmacological chaperone activity at beta-glucocerebrosidase N370S mutant in Gaucher disease patient-derived lymphoblasts with GCase N370S mutant assessed as increase in enzyme activity at 50 uM after 3 days by fluorimetric analysis relative to control