AnaSpec Introduces First FRET-based Cathepsin B Assay

AnaSpec announces the industry’s first FRET-based kit for Cathepsin B. The SensoLyte® 520 Cathepsin B Activity Assay Kit is a homogeneous assay that can be used for measuring Cathepsin B activity and for screening Cathepsin B inhibitors.

The substrate employs in this kit is a peptide sequence containing the QXL™ 520/HiLyte Fluor™ 488 FRET pair. In the intact sequence, the fluorescence of HiLyte Fluor™ 488 is quenched by QXL™ 520. Upon recognition and cleavage by Cathepsin B, the peptide is cleaved into two separate fragments, resulting in the release of HiLyte Fluor™ 488 fluorescence. Fluorescence can be continuously monitored at the green emission range of 520 nm (Ex= 488 nm). The long wavelength fluorescence and pH independent properties of HiLyte Fluor™ 488 mean less interference by autofluorescence of cellular components and test compounds, and the ability to measure Cathepsin B activity at its optimal low pH.