Immunogen
Recombinant full length protein, corresponding to amino acids 1-640 of Human Calpain 5 (NP_004046.2, UniProt ID: O15484).
Antigen Description
Calpain proteinases are defined currently as papain like neutral proteases that are calcium activated. Calpains 1 and 2 are composed of a large subunit, which is proteolytically active, and a small subunit (also called calpain 4), or enhancer protein, that is not proteolytically active. The other calpain proteins identified to date are not known to require a small subunit. Domains in the large subunit include the amino terminal domain I, the proteinase domain II, domain III, and the EF hand domain IV (Domain T in calpains 5 & 6). Calpain 5, also known as the human orthologue of TRA3, a C. elegans protein involved in sex determination, is located on chromosome 11 in humans, near calpain 1. Calpain 5 is an intracellular, calcium dependent cysteine protease. Calpain 5 domain T does not have the standard calpain EF hand domain for binding calcium, making it unclear whether it is calcium regulated. It is also unclear if calpain 5 plays any role in mammalian sex determination, since the enzyme is found in colon, kidney, liver and trachea and other tissues, as well as testis.