Magnesium requirements of human EndoG variants. (A) Electrophoresis analysis. EndoG variants were mixed with 0.1 μg of linear pUC18 dsDNA in EndoG buffer containing various amounts of magnesium. The reaction mixtures were incubated at 37°C for indicated periods. The resulting products were analyzed by 1.2% agarose gels. Lane C represents the reaction performed in the absence of EndoG. (B) Densitometric analysis. Activities are given as relative values with respect to the maximum activity for each variant.