Proteinase-activated receptors (PAR) are a subfamily of G-protein coupled, seven-transmembrane domain receptors, which are cleaved within the aminoterminal exodomain by certain serine proteinases at a specific peptide bond. Trypsin and mast cell tryptase, and more recently, the activated coagulation factors VIIa and Xa, have been identified as serine proteinases able to activate mammalian PAR-2. As already indicated, PAR-2 is believed to be involved in inflammation. This role for PAR-2 implies that elastase and cathepsin G would paradoxically display an anti-inflammatory property by disarming PAR-2.