3.2.2.8	-15°C, 1-3 mg of protein per ml, stable for 6 months	
3.2.2.8	3°C, cell extract heated for 10 min at 55°C before passage through a DEAE-cellulose column, enzyme thus purified loses 5% of activity after 30 days	
3.2.2.8	4°C, 0.032 mg protein per ml, over 70% of activity remained after 1 month