1.5.1.37	-80°C, His-tagged TftC loses about 50% activity after 2 months	
1.5.1.37	0°C, His-tagged TftC is unstable in the elution buffer containing 140 mM imidazole on ice, losing about 50% activity in 2 h	
1.5.1.37	4°C, stable over several days