Cathepsin G

Polymorphonuclear leukocytes (PMNs) contain abundant amounts of antibacterial proteins and proteolytic enzymes within peroxidase-positive azuphil granules. Some of these proteins show a spectrum of antibiotic activities and are collectively termed serprocidins. These include the serine proteases elastase, cathepsin G, proteinase 3 and a protein termed azurocidin which lacks proteolytic activity. Several line of evidence suggest that enzymes released extracellularly by PMNs as cathepsin G play an important role in the tissue destruction (Groutas, 1987) associated with a number of inflammatory diseases (Malech and Gallin, 1987) such as emphysema, (Groutas, 1987), ARDS (Warshawski et al., 1986) glomerulonephritis (Johnson et al., 1988) and rheumatoid arthritis (Saklatvala and Barrett, 1980). Cathepsin G acts as potent agonist of human platelet activation (Selak et al., 1988) leading to their aggregation and is reported to be involved in the activation of proMMP-2 via mechanism requiring MT1-MMP.