Aug 2008AnaSpecRequest Info
The SensoLyte 520 Cathepsin S assay kit from AnaSpec Inc. can be used to detect the activity of cathepsin S in biological samples or in purified enzyme preparations. The kit uses the long-wavelength 5-FAM/QXL 520-labeled Förster resonance energy transfer (FRET) peptide substrate for measuring enzyme activity. The fluorescence of 5-FAM is quenched by QXL 520 in the intact FRET peptide. When the active enzyme cleaves the FRET substrate, there is an increase of 5-FAM fluorescence, which can be monitored at an excitation wavelength of 490 nm and at an emission wavelength of 520 nm.