Figure 2.

The pH-dependent DNase activities of nuclease-ColE7. The DNase activity of nuclease-ColE7 in solutions with different pH varying from 3 to 10, was determined based on the DNA digestion patterns observed in a 4–20% TBE polyacrylamide gel using pUC18 plasmid DNA as the substrate. The DNase activity is indicated by the decreased amount of substrate DNA (the lane labeled with S). The nuclease-ColE7 has the optimal activity at ∼pH 9 in which most of the DNA substrates were digested.