Fig. (2) Activation of proMMP-9 by supernatants of the growth media of P. gingivalis (P.g.), P. intermedia (P.i.), P. micros, P. nigrescens (P.n.), F. nucleatum (F.n.) (Fig. 2) were studied by ECL Western blot. ProMMP-9 was incubated with the supernatants at 37o C for 6 h. All the strains were able to convert the 92 kDa proMMP-9 to the 60 and 77-82 kDa lower molecular size forms of MMP-9.