Recombinant Rat Cathepsin C/DPPI Protein, CF

Cathepsin C (CTSC), also known as dipeptidyl-peptidase I (DPPI), is a chloride-dependent cysteine protease in the papain family (1-3). It sequentially removes dipeptides from the free N-terminus of proteins and peptides. It has broad specificity except that it does not cleave proteins with a basic amino acid (Arg or Lys) in the N-terminal position or with a proline on either side of the scissile bond. Cathepsin C is synthesized with a large propeptide followed by a mature region, which is further cleaved into heavy and light chains during processing. The N-terminal region of the propeptide is known as the exclusion domain. It is present in the mature, active enzyme and regulates access of substrates to the active site (4). Cathepsin C is widely expressed and plays a major role in lysosomal degradation and enzyme activation. It activates granule serine proteases in cytotoxic T lymphocytes and natural killer cells (Granzymes A and B), mast cells (Tryptase and Chymase), and neutrophils (Cathepsin G and Elastase) by removing their N-terminal activation dipeptides (5).