Calpain (CALP)

entry list
Calpain (CALP) (EC is an intracellular cysteine protease whose two isoforms require either mM or _M free Ca2+ for activity. The large subunit of this heterodimer contains a domain homologous to sulfhydryl protease and five EF-hand domains at the C- terminus. The small subunit contains a Gly-rich domain at its N-terminus and five EF-hands at its C-terminus. In both subunits domains 1 & 2 and 3 & 4 form two lobes. The fifth domains of large and small subunits pair, as usually found in adjacent EF-hands, to join the two in the heterodimer [30].