1.5.1.7	-20°C, protein concentration above 0.1 mg/ml, pH 6.8, 1 mM EDTA, several months	
1.5.1.7	4°C, His-tagged mutant enzymes in 100 mM HEPES, 300 mM KCl and 300 mM imidazole at pH 8.0, several months, the mutant enzymes maintain stability and remain active	
1.5.1.7	4°C, mutant enzymes in 100 mM HEPES, 300 mM KCl, and 300 mM imidazole at pH 8.0, several months, no loss of activity