AnaSpec is pleased to announce the release of the industry’s
first FRET based Cathepsin B assay kit, the SensoLyte®
520 Cathepsin B Activity Assay Kit. 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 It
was shown that over expression 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
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.
Figure 1. Inhibition of Cathepsin B activity by Ac-LVK-CHO
as measured with SensoLyte®520 Cathepsin B activity Assay Kit.
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).