1.2.1.50	-20°C, 50 mM phosphate buffer, pH 7.0, 0.2 M NaCl, 5 mM dithiothreitol, 30-35% glycerol, 1 month	
1.2.1.50	-20°C, 50 mM phosphate buffer, pH 7.0, 0.2 M NaCl, 50 mM beta-mercaptoethanol, 30% glycerol, several months