6.1.1.16	-20°C, 50% glycerol	
6.1.1.16	-20°C, 50% glycerol, 1 mM DTE, at least 6 months, no loss of activity	
6.1.1.16	4°C, 50% glycerol, 0.5 mM DTT, 3 mM L-cysteine