The various activities of the recBC enzyme of Escherichia coli are differentially sensitive to reaction conditions. Although spermidine up to 50 mM and putrestine up to 40 mM in the presence of Mg2+ produce no significant alteration in the activities of the enzyme, low concentrations of Ca”’ have a dramatic effect. In the presence of 1 mM Ca2+, 1 mM Mg’+, and 5 mM ATP, the DNA-dependent ATPase ...
