IUBMB Enzyme Nomenclature


Accepted name: calpain-3

Reaction: Broad endopeptidase activity

Other name(s): p94; calpain p94; CAPN3; muscle calpain; calpain 3; calcium-activated neutral proteinase 3; muscle-specific calcium-activated neutral protease 3; CANP 3; calpain L3

Comments: This Ca2+-dependent enzyme is found in skeletal muscle and is genetically linked to limb girdle muscular dystrophy type 2A [1,4]. The enzyme is activated by autoproteolytic cleavage of insertion sequence 1 (IS1), which allows substrates and inhibitors gain access to the active site [4]. Substrates include the protein itself [3,4] and connectin/titin [2,5]. Belongs in peptidase family C2.

Links to other databases: BRENDA, EXPASY, KEGG, MEROPS, Metacyc, PDB, CAS registry number:


1. Sorimachi, H., Imajoh-Ohmi, S., Emori, Y., Kawasaki, H., Ohno, S., Minami, Y. and Suzuki, K. Molecular cloning of a novel mammalian calcium-dependent protease distinct from both m- and μ-types. Specific expression of the mRNA in skeletal muscle. J. Biol. Chem. 264 (1989) 20106-20111. [PMID: 2555341]

2. Sorimachi, H., Kinbara, K., Kimura, S., Takahashi, M., Ishiura, S., Sasagawa, N., Sorimachi, N., Shimada, H., Tagawa, K., Maruyama, K. and Suzuki, K. Muscle-specific calpain, p94, responsible for limb girdle muscular dystrophy type 2A, associates with connectin through IS2, a p94-specific sequence. J. Biol. Chem. 270 (1995) 31158-31162. [PMID: 8537379]

3. Rey, M.A. and Davies, P.L. The protease core of the muscle-specific calpain, p94, undergoes Ca2+-dependent intramolecular autolysis. FEBS Lett. 532 (2002) 401-406. [PMID: 12482600]

4. García Díaz, B.E., Gauthier, S. and Davies, P.L. Ca2+ dependency of calpain 3 (p94) activation. Biochemistry 45 (2006) 3714-3722. [PMID: 16533054]

5. Ono, Y., Torii, F., Ojima, K., Doi, N., Yoshioka, K., Kawabata, Y., Labeit, D., Labeit, S., Suzuki, K., Abe, K., Maeda, T. and Sorimachi, H. Suppressed disassembly of autolyzing p94/CAPN3 by N2A connectin/titin in a genetic reporter system. J. Biol. Chem. 281 (2006) 18519-18531. [PMID: 16627476]

[EC created 2007]

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