Identification of thiol-activated T-kininogenases in the rat and mouse submandibular glands.

T-kininogen is a unique protein(s) which is directed for synthesis following inflammation such as that caused by adjuvant arthritis and carrageenin. The properties of the protein include thiol-protease inhibition and the potential to act as a substrate to release Ile-Ser-bradykinin (T-kinin). During the inflammatory response, free T-kinin is found in the blood and inflammatory fluids indicating that T-kininogenase (T-kgnase) enzymes exist that release T-kinin and perhaps related T-kinins involved in inflammation. We report here that T-kininogenases have been found in the rat and mouse submandibular glands and in rat peritoneal white cells. The pH optimum is about 8.0. The enzymes must be thiol-activated. Thus, the rat has the complete T-kgnase-T-kinin system. Since T-kininogen is a member of the superfamily of cysteine protease inhibitors, members of the superfamily may be directed for synthesis in inflammatory diseases including ascites in other species including humans.