SensoLyte® 520 Calpain Kit – Long Wavelength Assay

AnaSpec is pleased to announce the release of the industry's first longest wavelength FRET based calpain assay, the SensoLyte® 520 Calpain Activity Assay Kit. Optimized for detecting calpain activity, this kit contains a novel internally quenched 5-FAM/QXL™ 520 FRET substrate. Cleavage of this FRET substrate generates two separate fragments. The subsequent release of 5-FAM fluorescence can be monitored at excitation/emission= 490/520 nm. Increase in fluorescence is proportional to the calpain activity. The assay can detect both calpain 1 (m) and 2 (m) activities and is ideal for kinetic study of these enzymes. The long wavelength fluorescence of 5-FAM is less interfered by the autofluorescence of components in biological samples and test compounds.

Calpains are a family of intracellular cysteine proteases, which consists of at least 15 ubiquitous and tissue-specific isoforms.1 The best-characterized calpains are the isoforms µ- and m-calpain, which are also known as calpain 1 and calpain 2, respectively. Calpains are calcium-dependent and function by modulating the biological activities of many proteins through selective cleavage.2 Studies have demonstrated that calpains are implicated in a variety of calcium-regulated cellular processes such as signal transduction, cell proliferation, differentiation, cell cycle progression, apoptosis, and platelet activation. Deregulation of calpains activities has been implicated in various pathological phenomena such as atherosclerosis, Alzheimer's disease, diabetes, and cancer.3, 4 Calpains represent potential therapeutic targets for drug development.5, 6

An AMC based calpain assay, the SensoLyte® AMC Calpain Assay, is also available from AnaSpec.

SensoLyte® 520 Calpain Assay (Cat# 72149)

SensoLyte® AMC Calpain Assay (Cat# 72150)


Fluorimetric, FRET based (5-FAM/QXL™ 520)



Ex/Em= 490/520 nm

Ex/Em= 354/442 nm




Lowest Detection Limit

0.04 uM

0.25 uM

Kit size (96-well plate)

100 tests

100 tests

Assay time

As short as 1h

As short as 1h

Inhibitor screening


Catalog #

SensoLyte® 520 Calpain Activity Assay Kit *Fluorimetric* NEW


SensoLyte® AMC Calpain Activity Assay Kit *Fluorimetric* NEW


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1. Goll, DE. et al. Physiol. Rev. 83, 731 (2003).
2. Suzuki K, et al. Diabetes. 53 Suppl 1, S12 (2004).
3. Zatz M, et al: N Engl J Med. 352, 2413 (2005).
4. Branca D. Biochem Biophys Res Commun. 322, 1098 (2004).
5. Carragher NO. Curr Pharm Des. 12, 615 (2006).
6. Saez ME. et al. Drug Discovery Today 11, 917 (2006).