4.6.1.21	-15°C, stable, withstands freezing and thawing	
4.6.1.21	-196°C, stable, withstands freezing and thawing	
4.6.1.21	-20°C	
4.6.1.21	-20°C, 0.1 mg protein per ml Tris-HCL elution buffer, stable for about 3 weeks	
4.6.1.21	-20°C, lyophilized enzyme, stable for about 3 weeks