| Assay Method Information | |
| | Fluorescence Based Assay |
| Description: | The fluorescence based assay to monitor the activity of human nSMase2 in the presence or absence of potential inhibitors has been described recently. Figuera-Losada, et al. Lysate of cells expressing recombinant nSMase2 is used to catalyze the hydrolysis of sphingomyelin (SM) to ceramide and phosphorylcholine. Phosphorylcholine undergoes dephosphorylation in a reaction catalyzed by alkaline phosphatase (4 U/mL) to produce choline which in turn is oxidized by choline oxidase (0.1 U/mL) to betaine and hydrogen peroxide (H2O2). Hydrogen peroxide is made to react with Amplex red (50 μM) in the presence of horseradish peroxidase (HRP, 1 U/mL) to generate the fluorescent molecule resorufin. Generation of fluorescence is monitored by measuring relative florescence units (RFU) with excitation at 530 nm and emission at 590 nm. Extent of fluorescence is directly proportional to the extent of SM hydrolysis. Substrate stock solution is prepared in 2% Triton X-100 and sonicated for 1 min. Reactions are carried out for 1 h at 37° C. in 100 mM Tris-HCl pH 7.4, 10 mM MgCl2, 0.2% Triton X-100. This assay has been optimized in 384-well format (50 μL total volume per well) under conditions where nSMase2-catalyzed hydrolysis of SM is linear with respect to nSMase2 concentration, time of incubation and SM concentration (FIGS. 3A-3C). The assay has high reliability (Z′=0.8-0.9). It is used for compound screening, IC50 determinations and mode of inhibition studies |
| Affinity data for this assay | |
|---|---|
| If you find an error in this entry please send us an E-mail | |