CATHEPSIN-B IN GINGIVAL CREVICULAR FLUID OF ADULT PERIODONTITIS PATIENTS - IDENTIFICATION BY IMMUNOLOGICAL AND ENZYMOLOGICAL METHODS

Cathepsin B (EC 3.4.22.1), a typical lysosomal cysteine proteinase was identified immunologically with anti-human cathepsin B antibody in in flammatory exudate, gingival crevicular fluid (GCF) of adult periodont itis patients. The sensitive enzyme immunoassay (EIA) system initially developed, was rarely influenced by the presence of endogenous cystei ne proteinase inhibitors, cystatin(s), indicating that it is possible to quantify the gross amount of cathepsin B including free enzyme form s and enzyme-inhibitor complex forms using this EIA system. The cathep sin B levels in GCF as determined by EIA and the activity measured wit h Z-Arg-Arg-MCA showed positive and significant correlation with vario us clinical parameters. Immunoblotting analysis revealed that the mole cular form was a 29 kDa mature enzyme. More than 95% of Z-Arg-Arg-MCA hydrolytic activity in each GCF sample was inhibited by CA-074, specif ic inhibitor of cathepsin B. These results strongly suggested that the gross amount of cathepsin B in GCF as well as its activity level is c losely associated with the severity of the disease and that cathepsins B play an important role in the pathogenesis of periodontitis.