Calpain

**Semantic type:** Amino Acid, Peptide, or Protein|Enzyme

**Definition:** A class of calcium-dependent thiol-proteases that proteolytically cleave a wide variety of cytoskeletal, membrane-associated, and regulatory proteins. There are two main isoforms of the protein, which differ in their calcium requirement for activation. These enzymes have been linked to both acute and chronic neurodegenerative processes, such as: ischemia, trauma, and Alzheimer's disease.

**Synonyms:** - Calcium-Activated Neutral Protease - Calcium-Activated Neutral Proteinase - Papain-Like Cysteine Protease