2.7.1.86 -30°C, 20 mM Tris-HCl buffer, pH 7.8, 0.2 M ammonium sulfate, 20 mM MgCl2, 2 mM EDTA, stable for 1 month or more 2.7.1.86 0-5°C, 20 mM Tris-HCl buffer, pH 7.8, 0.2 M ammonium sulfate, 20 mM MgCl2, 2 mM EDTA, stable for 7 days 2.7.1.86 4°C or -20°C, 95% loss of activity after overnight storage