抄録
To elucidate the possible roles of cathepsin B in bone resorption of cholesteatoma, cathepsin activity was investigated in cholesteatoma epithelium, subepithelial granulation tissue, mastoid bone and external ear canal skin. The enzyme extracted from tissues was proven to be lysosomal cathepsin B by SDS gel electrophoresis in use of human type III collagen, α-N-benzoyl-DL-arginine-2-naphthylamide HCl (BANA) was supposed to be specific for cathepsin B, and so BANA-hydrolase activity was measured as collagen degrading cathepsin. The results clarified that tissues had cathepsin B with its optimal pH 6.0, and that cathepsin B activity revealed a significant increase in granulation tissue. It is suggested that cathepsin B activity is shown to be essential for the degradation of collagen by lysosomal extracts and may provide an alternative route for breakdown in physiological and pathological situations.
