September 21, 2010 -- AnaSpec is pleased to announce the release of the SensoLyte® 520 Cathepsin B Activity Assay Kit, the industry’s first FRET-based kit for Cathepsin B. This homogeneous assay 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.
Cathepsin B is a cysteine proteinase belonging to the papain family with broad exo- and endopeptidase activity.1 Overexpression of Cathepsin B has been shown to correlate with metastatic potential and the enzyme is implicated in the ability of tumor cells to invade the extracellular matrix and to metastasize to secondary sites.2-3 Cathepsin B levels are also markedly elevated in a variety of neurological disorders including Alzheimer’s disease (AD).4
SensoLyte® 440 Cathepsin B Assay Kit containing an AMC labeled peptide substrate, with emission in the blue range (Ex/Em=354/442 nm) is also available.
References
1. Guicciardi, M. et al. J. Clin. Invest. 106, 1127 (2000)
2. Sloane, B. et al. Science. 212, 1151 (1981).
3. Sloane, B. et al. Cancer Metastasis Rev. 3, 249 (1984).
4. Haque, A. et al. CNS Neurol Disord Drug Targets 7, 270 (2008).
