Assay Report Card

ID: ALA3888177

Type: Binding

Description: In Vitro Enzymatic Cathepsin D FRET Assay: Recombinant Cat D was expressed in CHO cells. The assay buffer for CathepsinD is 0.05 M citrate pH 3.5, 10% DMSO final, 5 mM CHAPS. The Cat D enzyme (9 nM) is pre-incubated for one hour with inhibitors, typically in about 1 uL of DMSO according to a serial dilution, is added thereto. The assays are effectively started by the addition of different FRET substrates (20 nM for Cat D) and the combination is incubated for one hour. The FRET assay is terminated with by addition of Tris buffer, which raises the pH to neutrality, and the fluorescence is determined. The FRET substrate is a peptide with commercially available fluorophore and quencher, on opposite sides of the BACE cleavage site. The Cat D substrate peptide sequence is based on sequence #1 of Table 1 from Gulnik et al. FEBS Letters v413 p 379-384 1997. Proteolytic cleavage of the FRET substrate releases quenching of fluorescence (Cat D excitation 500 nm and emission 580 nm).

Organism: Homo sapiens

Cell type: CHO