FIG. 2.

Zymogram stains of catalatic and peroxidatic activities. Cell extracts were electrophoresed under nondenaturing conditions and stained for catalatic (left) or diaminobenzidine peroxidatic (right) activity. Lanes 1, strain PB126 (katA null); lanes 2, strain PB140 (katA katB null), 275 μg of cell protein from an overnight culture per lane; lanes 3, 4, and 5, wild-type strain JR32 from, respectively, exponential-phase cultures (optical density at 600 nm, 0.69 and 1.45, respectively) and a 48-h culture (250 μg of cell protein per lane).