1.5.3.16	-20°C, activity decreased by about 90% after 1 day, mutant enzyme deprived of all but two cysteine residues (C263/C429)	
1.5.3.16	-20°C, stable for 2 days minimal loss of activity, complete loss of enzyme activity after 14 days	
1.5.3.16	6°C, activity decreased by about 90% after 1 day, mutant enzyme deprived of all but two cysteine residues (C263/C429)