2.4.2.18	-15°C, crude extract is stable for 2 years	
2.4.2.18	-25°C, 500 mM Tris-HCl, pH 7.5, 2 mM EDTA, 2 mM MgCl2, 5% loss of activity after 2 weeks	
2.4.2.18	4°C, 10% loss of activity after 2 months	
2.4.2.18	addition of 10% glycerol at -70°C and then dropping the solution into liquid N2, can be thawed and frozen several times without loss of activity