Assay Report Card

ID: ALA3705433

Type: Binding

Description: HTRF FRET Assay: A homogeneous time-resolved FRET assay was used to determine IC50 values for inhibitors of the soluble human BACE1 catalytic domain. This assay monitored the increase of 620 nm fluorescence that resulted from BACE1 cleavage of an APPswedish APPswe mutant peptide FRET substrate (QSY7-EISEVNLDAEFC-Europium-amide). This substrate contained an N-terminal QSY7 moiety that served as a quencher of the C-terminal Europium fluorophore (620 nm Em). In the absence of enzyme activity, 620 nm fluorescence was low in the assay and increased linearly over 3 hours in the presence of uninhibited BACE1 enzyme. Inhibition of BACE1 cleavage of the QSY7-APPswe-Eu substrate by inhibitors was manifested as a suppression of 620 nm fluorescence.Varying concentrations of inhibitors at 3x the final desired concentration in a volume of 10 ul were preincubated with purified human BACE1 catalytic domain (3 nM in 10 ul) for 30 minutes at 30 C. in reaction buffer containing 20 mM Na-Acetate pH 5.0.

Organism: Homo sapiens