SensoLyte® Cathepsin Assays – B, D, E, G, K, L & S


Cathepsins (CTS's) are a family or proteases found in eukaryotic cells.1 Involved in many important physiologic processes, cathepsins can be classified as serine proteases (Cathepsins A & G), aspartic proteases (Cathepsins D & E) and cysteine proteases (Cathepsins B, C, F, H, K, L, O, S, W, V & Z).1

AnaSpec is pleased to offer a series of fluorimetric long wavelength, sensitive SensoLyte® 520 assay kits for enzyme activity determination of Cathepsins G, D, E, B, K, L and S. These kits employ a FRET (Fluorescence Resonance Energy Transfer) peptide substrate that emits in the green range of 520 nm, with excitation at 490 nm. The advantage of using longer wavelength emitting substrates means that autofluorescence from cellular components and test compounds is minimal; thus making the kits more sensitive. Furthermore, the use of HiLyte Fluor™ 488 (except for Cathepsin S, which uses 5-FAM) as the FRET donor (fluorophore) results in a more stable fluorescent signal, since HiLyte Fluor™ 488 is resistant to acidic pH.

Cathepsin

Figure 1. A schematic representation of a FRET peptide as found in SensoLyte® 520 Cathepsin kits (except for Cathepsin S which uses 5-FAM instead of HiLyte Fluor™ 488) in which the fluorescence of HiLyte Fluor™ 488 is released after enzymatic cleavage.

Table 1. A listing of the SensoLyte® Cathepsin kits. Kits providing conventional FRET (Mca/Dnp) or fluorogenic substrates for cathepsins are also available.

Product

Catalog #

SensoLyte® 520 Cathepsin B Assay Kit *Fluorimetric*

72164

SensoLyte® 440 Cathepsin B Assay Kit *Fluorimetric*

72165

SensoLyte® 520 Cathepsin D Assay Kit *Fluorimetric*

72170

SensoLyte® 390 Cathepsin D Assay Kit *Fluorimetric*

72098

SensoLyte® 520 Cathepsin E Assay Kit *Fluorimetric* NEW

72222

SensoLyte® 390 Cathepsin E Assay Kit *Fluorimetric* NEW

72221

SensoLyte® 520 Cathepsin G Assay Kit *Fluorimetric*

72185

SensoLyte® Rh110 Cathepsin G Assay Kit *Fluorimetric*

72186

SensoLyte® 520 Cathepsin K Assay Kit *Fluorimetric*

72171

SensoLyte® Rh110 Cathepsin K Assay Kit *Fluorimetric*

72152

SensoLyte® 520 Cathepsin L Assay Kit *Fluorimetric* NEW

72218

SensoLyte® Rh110 Cathepsin L Assay Kit *Fluorimetric* NEW

72217

SensoLyte® 520 Cathepsin S Assay Kit *Fluorimetric*

72099

SensoLyte® 440 Cathepsin S Assay Kit *Fluorimetric*

72100



Figure 2. Titration of Cathepsin D with peptide substrates with the same sequence, but different FRET pairs.
Substrates were incubated with different dilutions of Cathepsin D for 1 hour. HiLyte Fluor™ 488/QXL™ 520-based cathepsin substrate provided better sensitivity and signal/background ratio than the same peptide sequences coupled with the 5-FAM/QXL™ 520 or Mca/Dnp FRET pair.

Click "The Optimization of FRET Substrates for Detection of Cathepsins Activity" to view a poster presented at a previous scientific conference.

Please contact us (biology@anaspec.com) to request for cross-reaction information of these kits or for technical inquiries on these and other SensoLyte® assay kits.

References:

  1. Conus, S. Medical Intelligence doi:10.4414/smw.2010.13042.