Calpain

Calpain
Crystal structure of the peptidase core of Calpain II.
Identifiers
SymbolCalpain
PfamPF00648
Pfam clanCL0125
InterProIPR001300
SMARTCysPc
PROSITEPDOC50203
MEROPSC2
SCOP21mdw / SCOPe / SUPFAM
Available protein structures:
PDB  1tl9​ A:55-354; 1kxr​ B:55-354; 1tlo​ A:55-354; 2ary​ B:55-354; 1zcm​ A:55-353; 1mdw​ B:45-344; 1u5i​ A:45-344; 1kfx​ L:45-344; 1kfu​ L:45-344; 1ziv​ A:42-337 IPR001300 PF00648 (ECOD; PDBsum)  
AlphaFold
calpain-1
Identifiers
EC no.3.4.22.52
CAS no.689772-75-6
Databases
BRENDAenzyme data
ExPASyNiceZyme view
KEGGenzyme entry
MetaCycmetabolic pathway
Rheareactions
PDB structuresRCSB PDB PDBe PDBsum
Search
PMCarticles
PubMedarticles
NCBIproteins
calpain-2
Identifiers
EC no.3.4.22.53
CAS no.702693-80-9
Databases
BRENDAenzyme data
ExPASyNiceZyme view
KEGGenzyme entry
MetaCycmetabolic pathway
Rheareactions
PDB structuresRCSB PDB PDBe PDBsum
Search
PMCarticles
PubMedarticles
NCBIproteins

A calpain (/ˈkælpeɪn/; EC 3.4.22.52, EC 3.4.22.53) is a protein belonging to the family of calcium-dependent, non-lysosomal cysteine proteases (proteolytic enzymes) expressed ubiquitously in mammals and many other organisms. Calpains constitute the C2 family of protease clan CA in the MEROPS database. The calpain proteolytic system includes the calpain proteases, the small regulatory subunit CAPNS1, also known as CAPN4, and the endogenous calpain-specific inhibitor, calpastatin.