6.1.1.1	-15°C, rapid loss of activity, 0.05 M GSH plus 0.005 M EDTA stabilizes	
6.1.1.1	-20°C	
6.1.1.1	-20°C, 0.025 M potassium phosphate buffer, pH 6.7, 0.01 M 2-mercaptoethanol, 50% glycerol, no loss of activity in 6 months	
6.1.1.1	-20°C, 4 months stable	
6.1.1.1	4°C, 20 mM Tris-HCl buffer, pH 7, 80% loss of activity within 48 h, 5% loss of activity in presence of 10% glycerol and 3 mM 2-mercaptoethanol