1.2.1.31	-20°C, 0.02 mM potassium phosphate buffer, pH 7.0, 5 mM 2-mercaptoethanol, 3 months	
1.2.1.31	-20°C, 50% v/v glycerol, rapid loss of activity	
1.2.1.31	0°C, 50% loss of activity, 24 h