Detection of Porphyromonas gingivalis in gingival exudate by a dipeptide-enhanced trypsin-like activity

Porphyromonas gingivalis in subgingival plaque is an important risk factor for future periodontal attachment loss in susceptible adults. The elimination of P. gingivalis is usually concomitant with a healing process. Therefore, it should be valuable to have an easy chairside method to follow the effect of periodontal treatment on P. gingivalis detection as well as on its eventual reappearance during the maintenance period. We have previously reported the stimulation of amidolytic activity of P. gingivalis by the addition of glycyl-glycine to the assay buffer. In this study we determined the proportions of P. gingivalis, Prevotella intermedia, Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, Capnocytophaga spp, Campylobacter rectus, and Eikenella corrodens by cultivation technique and the amidolytic activity, using N-benzoyl-L-arginine-p-nitroanilide (BAPNA) as substrate, in gingival exudate before and during a 3-year treatment and maintenance period. P. gingivalis was the only species yielding a high and persistent correlation to stimulated amidolytic activity (P values < or = 0.0001) on both site (r = 0.5) and subject (r = 0.8) level. Testing pure cultures of suggested periodontal pathogens for effect of glycyl-glycine on amidolytic activity, we found that of P. gingivalis to be 5.9-fold increased. The amidolytic activity of Treponema denticola was only slightly stimulated (ratio with/without glycyl-glycine = 1.2) and that of Capnocytophaga slightly inhibited (ratio with/without glycyl-glycine = 0.8). The outcome of this study has the potential to be used for the development of a simple, rapid, and inexpensive assay for a qualitative and quantitative determination of P. gingivalis in gingival crevicular fluid.

A novel chymotrypsin-like serine proteinase from human lung

A novel chymotrypsin-like serine proteinase with an M(r) of 30,000 has been isolated from human lung tissue. The enzyme was active on both the synthetic substrate Suc-Ala-Ala-Pro-Phe-SBzl and azocasein, with a pH optimum of 8.0 and a preference for high concentrations of NaCl for maximum activity. The proteinase was inhibited by diisopropylfluorophosphate, tosyl-phenylalanyl-chloromethane, chymostatin, soybean trypsin inhibitor, alpha-1-antichymotrypsin, and alpha-2-macroglobulin. It was not inhibited by C-1 inhibitor or aprotinin. An N-terminal sequence of IIGGTESKPDSRPYMALLQIVEPAVH indicated that this enzyme is a member of a superfamily of serine proteinases comprising cathepsin G, chymase, and the granzymes; however, it is clearly distinct from these enzymes on the basis of both physical and chemical properties.