Lysine-specific proteolytic activity responsible for forsythia detaching factor modification.

OBJECTIVES: The objective of the present study was to clarify the lysine-specific proteolytic activity derived from periodontal pathogens responsible for Forsythia detaching factor (FDF) modification. DESIGN: The activity responsible for FDF modification in Tannerella forsythia and Porphyromonas gingivalis were evaluated by colorimetric assay using Ac-Arg-Ala-Lys-p-nitroaniline as a substrate. FDF modification in T. forsythia and P. gingivalis were evaluated by Western blotting using recombinant FDF (rFDF) as a substrate. Furthermore, the activity in GCF of 20 patients with periodontitis and 10 healthy subjects was also evaluated by colorimetric assay. Bacteria in subgingival plaque were detected using polymerase chain reaction. RESULTS: The activity of both bacteria in colorimetric assay were 21.35 unit (P. gingivalis) and 3.61 unit (T. forsythia), respectively. Western blot analysis revealed that P. gingivalis was found to efficiently degrade rFDF and T. forsythia partially cleaved rFDF. The activity in GCF from patients with periodontitis (clinically healthy sites: CH, deep bleeding sites: DB and deep non-bleeding sites: DNB) was significantly higher than those from healthy subjects (healthy sites: H). Among the patients with periodontitis, the activity from CH was significantly lower than those from DB and DNB. T. forsythia was detected in 68.4% of DNB, in 78.4% of DB and in none of CH. P. gingivalis was detected in 63.2% of DNB, in 84.0% of DB and in 10.5% of CH. No bacterium was detected in healthy subjects. CONCLUSION: The lysine-specific proteolytic activity responsible for FDF modification correlates with the presence of major periodontal pathogens.

Modification of forsythia detaching factor by gingival crevicular fluid in periodontitis.

OBJECTIVES: Forsythia detaching factor (FDF) is a virulence factor of Tannerella forsythia detected as a mixture of the 60-kDa form of FDF and the 28-kDa C-terminal fragment (FDFc). The objective of the present study was to clarify the proteolytic activity of gingival crevicular fluid (GCF) from patients with periodontitis and healthy subjects using recombinant FDF (rFDF) as substrate. DESIGN: Eleven patients with periodontitis and 6 healthy subjects were recruited. Modification of rFDF and subsequent production of rFDFc by proteolytic activity of GCF was determined by Western blotting. Proteolytic activity of GCF was evaluated using an Ac-Arg-Ala-Lys-p-nitroaniline substrate. Correlation analysis between two different sets of variables was performed. Variables used in this analysis were proteolytic activity, clinical parameters, relative band density of rFDFc and those of rFDF. RESULTS: Proteolytic activity in GCF was significantly higher in patients with periodontitis than in healthy subjects. Production of rFDFc was determined by treatment of rFDF with GCF from patients with periodontitis and with GCF from healthy subjects. Correlations between clinical parameters and proteolytic activity in GCF were significantly positive. On the other hand, correlations between relative band density of rFDFc or rFDF on Western blot and cleaving activity or clinical parameters were significantly negative. CONCLUSION: The detected extend of GCF-activity generating rFDFc from rFDF and/or even further degrading rFDF correlates with severity of periodontitis.