Calpain-Glo Protease Assay

Simple Protocol Offers Fast, Sensitive Results

The Calpain-Glo™ Protease Assay is a homogeneous, luminescent assay that measures calpain 1 (u) and 2 (m) activities. Calpains are a family of calcium-activated cysteine proteases involved in cleaving a wide variety of proteins. Calpains modulate the biological activities of their substrates via limited proteolysis.

The Calpain-Glo™ Protease Assay provides a succinyl, proluminescent calpain substrate, Suc-LLVY-aminoluciferin, in a buffer system optimized for calpain and luciferase activities. The addition of the calpain reagent in an "add-mix-measure" format results in calpain cleavage of the substrate and rapid development of a "glow-type" luminescent signal produced by the luciferase reaction. The signal is proportional to the amount of calpain activity present. The assay is designed for use with purified enzyme preparations.

• Designed for measuring calpain activity and/or inhibition in a multiwell format and easy to automate.
• Well suited for rapidly autolysed enzymes like calpain; maximum sensitivity is reached in as little as 10 minutes, while the enzyme is fully active.
• Up to 1,000 times more sensitive than competitive fluorometric assays. The luminescent assay avoids inherent fluorescent background signals, providing excellent signal-to-background readings. The assay is linear over 4 logs of calpain concentration.

1. Moldoveanu, T. et al. (2002) Cell 108, 649–60.