2.3.1.86	-15°C, stable in 90% ammonium sulfate solution containing 0.1 M potassium phosphate, pH 6.5, and 1 mM DTT	
2.3.1.86	-20°C, 1 month	
2.3.1.86	4°C, precipitate in 50% ammonium sulfate solution, several days