FIG. 4.

Effect of Li⁺, Na⁺, and K⁺ on the activity of M. jannaschii I-1-Pase toward 2.5 mM I-1-P in 50 mM Tris HCl, pH 8.0, with 10 mM MgCl₂ at 85°C for 1 min. The activities are normalized to the value for the assay without the monovalent cation salt added. The error bars indicate standard deviations.