2.4.2.17	-15°C, several months	
2.4.2.17	-20°C, 50 mM Tris-HCl, pH 7.5, 0.4 mM DTT and one protease inhibitor per litre, 50% v/v glycerol, long term storage	
2.4.2.17	4°C, 0.01 M Tris, 0.10 M NaCl, 0.4 mM histidine, 2.8 mM 2-mercaptoethanol, 0.5 mM EDTA, pH 7.5, 50% loss of activity after several days	
2.4.2.17	4°C, HEPES buffer pH 7.5, final ammonium sulfate microcrystalline enzyme in 60% saturated ammonium sulfate, 0.1 M NaCl, 0.01 M Tris, 1.5 mM EDTA, 10 mM dithiothreitol, stable for 1 month, greater than 95% activity retained	
2.4.2.17	storage in liquid nitrogen of quick-frozen enzyme in HEPES buffer pH 7.5, 0.1 M NaCl, 0.01 M Tris, 0.5 mM EDTA, 1 mM dithiothreitol, 1 mM histidine, indefinitely stable, preserves 100% activity. The critical factor for stability seems to be the maintenance of a sulfhydryl-reducing environment, high dithiothreitol concentrations has no adverse effect at either 0°C or 37°C