FIG. 4.
Casein zymography of S. gordonii protease activity. The supernatant fluids from broth cultures of S. gordonii Challis or sgc mutants grown overnight were concentrated 500-fold and applied to ready-made casein gels. Concentrated supernatant fluids from parental strain Challis (lane 1), insertional mutant 41A9 (lane 2), and two clones of knockout mutant BYW1 (lanes 3 and 4) were used. The approximate position of the 160-kDa band is indicated by the arrowhead.