2.7.1.44	-20°C, crude recombinant enzyme is stable	
2.7.1.44	-20°C, purified enzyme preparations lose more than 90% of activity within one week	
2.7.1.44	-80°C, stable for several months when diluted with glycerol to 25% (v/v) and flash-frozen in liquid nitrogen	
2.7.1.44	4°C, 0.05 M mercaptoethanol, stable up to 10 days