Figure 2.

(A) Dependence of cleavage activity on the concentration of Li⁺ ions. The activity increased linearly with the concentration of Li⁺ ions until ∼3 M. Reaction conditions: 25 mM Bis-Tris, pH 7.5, and varying concentrations of Li⁺ ions as indicated. (B) Dependence on pH of the activity in 2 M Li⁺ ions. The Li⁺-containing buffer used in this experiment included Bis-Tris propane and Tris. The cleavage rate increased linearly with pH, yielding a slope of 0.9.