Main characteristics of the endogenous inhibitors of elastase, proteinase 3, and cathepsin G
| Reactive site | Target Proteases | Source | |
|---|---|---|---|
| Serpin | |||
| α1-PI | Met358–Ser359 | Elastase, proteinase 3, cathepsin G, trypsin, plasmin, thrombin, chymotrypsin | Plasma, neutrophil |
| ACT | Leu358–Ser359 | Cathepsin G, chymase, chymotrypsin | Plasma |
| MNEI | Phe343–Cys344 | Cathepsin G, chymase, kallikrein 3 | Neutrophil, macrophage |
| Cys344–Met345 | Elastase, proteinase 3 | ||
| PI6 | Arg341–Cys342 | Cathepsin G | Placenta, granulocytes |
| PI9 | Glu340–Cys341 | Granzyme B, caspase 1 | Lymphocyte T cells |
| Cys341–Cys342 | Elastase | Endothelial cells, epithelial cells | |
| Chelonianin | |||
| SLPI | Leu72–Met73 | Elastase, cathepsin G, chymase, chymotrypsin | Epithelial cells, seminal plasma, neutrophil, macrophage |
| Elafin | Ala24–Met25 | Elastase, proteinase 3 | Bronchial secretions, skin, seminal plasma |