Figure 5. Effect of divalent cations on tear nucleases. The activities of the minor endonuclease (A) and TL (B) in the presence MgCl₂ (■), CaCl₂ (◯), or CoCl₂ (●) as well as MgCl₂. in combination with 1 mM with CaCl₂ (▲) is shown in these graphs. Values are representative of the experiments run in triplicate. The standard deviations of all points varied between 10%–15%. Activity for both endonucleases dependent on the presence of MgCl₂. While CaCl₂ is not required for activity the effect of effect of MgCl₂ and CaCl₂ is synergistic for both endonucleases.