... 6 and 10 and from 0-42°C and requires 1-2 mM Mg2+ for activation. The enzyme is also ... as the amount of enzyme that causes a ΔA260 of 1.0 in30 min, which corresponds to complete digestion of 37 ... μg of DNA. Standard reaction conditionsare 1 mg/ml sonicated DNA substrate in 50 mM Tris-HCl pH 8 ... .0, 0.1 mg/ml BSA, 1 mM MgCl2,incubated at 37°C; measured as perchloric ...