FIG. 5.

Protease activation in the extracellular protein fraction from P. gingivalis FLL92. P. gingivalis was grown to late log phase (OD₆₆₀ of 0.8) in 1 liter of BHI broth supplemented with hemin and vitamin K. Acetone (37.5%)-precipitated proteins were mixed with 8 M urea and incubated at 4°C for 1 h. The urea was slowly removed from the mixture by centrifugation (10,000 × g) in a Millipore filtration unit with the addition of increasing volumes of 100 mM Tris-HCl buffer (pH 7.4). Activities against BAPNA were tested according to the methods of Potempa et al. (36). The results shown are representative of four independent experiments.