Cathepsin S

Cathepsin S is a lysosomal cysteine protease of the papain family. Human Cathepsin S is synthesized as a preproenzyme of 331 amino acid residues consisting a signal peptide (residues 1 - 16), a pro region (residues 17 - 114), and the mature enzyme (residues 115 - 331).

Image: Cathepsin S staining of immersion fixed paraffin-embedded sections of human lymph node(15 µg/mL overnight at 4 °C). Tissue was stained using the Anti-Goat HRP-DAB (brown)and counterstained with hematoxylin (blue).

Cathepsin S is expressed in human adipose tissue and certain tumors. It has also been shown to be able to function as an elastase over a broad pH range in alveolar macrophages. Transcript variants utilizing alternative polyadenylation signals exist for this gene.