Dipeptidyl peptidase II- and IV-like activities in gingival tissue and crevicular fluid from human periodontitis lesions.

Gingival tissue and gingival crevicular fluid were collected from patients with chronic periodontitis. Gel filtration chromatography of crude tissue extracts yielded separate fractions active against Lys-Ala-7-amino-4-trifluoromethyl-coumarylamide (AFC) at acid pH and Gly-Pro-AFC at alkaline pH. The molecular weights, pH optima and inhibitor responses of these activities were consistent with those of dipeptidyl peptidases (DPP) II and IV, respectively. When tested with the same substrates, crevicular fluid was also found to contain DPP II- and IV-like activities with very similar pH profiles and inhibitor responses to those in tissue. The close resemblance suggested that the crevicular fluid enzymes were derived mainly from inflamed gingival tissues. Slight differences in the DPP II-like activities might be explained by the additional presence in crevicular fluid of enzymes from subgingival bacteria. With use of appropriate buffers, a third substrate, Ala-Pro-AFC, gave selective detection of both DPP II- and IV-like activities in tissue and crevicular fluid. Assays with Ala-Pro-AFC had the advantage of greater sensitivity, especially with DPP II-like activity. Raised levels of this enzyme have previously been found in the gingiva of periodontitis patients and thus DPP II-like activity in crevicular fluid might prove of value in monitoring disease activity.