Enzyme | Expression pattern in lung tissue (immunhistochemistry) | Proteolytic activity |
Cathepsin B | Ubiquitous | Carboxypeptidase |
| Strongly in bronchial epithelial cells and macrophages | Endoprotease |
Cathepsin H | Ubiquitous | Aminopeptidase |
| Strongly in macrophages and type‐II‐epithelial cells | Endoprotease |
Cathepsin K | Bronchial epithelial cells | Endoprotease |
| Macrophages (?) | |
Cathepsin L | Ubiquitous | Endoprotease |
| Strongly in bronchial epithelial cells and macrophages | |
Cathepsin S | Macrophages | Endoprotease |
Cathepsin X | Ubiquitous | Carboxypeptidase |
| Strongly in macrophages | |
Cathepsin W | Strongly in macrophages | ? |
| Some lymphocytes | |