[5][6] Cathepsin C appears to be a central coordinator for activation of many serine proteases in immune/inflammatory cells.

The cDNAs encoding rat, human, murine, bovine, dog and two Schistosome cathepsin Cs have been cloned and sequenced and show that the enzyme is highly conserved.

The signal peptide is removed during translocation or secretion of the pro-enzyme (pro-cathepsin C) and a large N-terminal proregion fragment (also known as the exclusion domain),[9] which is retained in the mature enzyme, is separated from the catalytic domain by excision of a minor C-terminal part of the pro-region, called the activation peptide.

Defects in the encoded protein have been shown to be a cause of Papillon-Lefevre disease,[10][11] an autosomal recessive disorder characterized by palmoplantar keratosis and periodontitis.

Once activated by cathepsin C, the proteases are capable of degrading various extracellular matrix components, which can lead to tissue damage and chronic inflammation.