2.7.1.175 | 4°C, purified recombinant His-tagged enzyme, 7 days, about 40% of activity remaining, at pH 7.5, most of the activity is lost after freeze/thawing at -20°C. 10 mM maltose only slightly improve the stability at 4°C to about 50% of maximal activity, but addition of 50 mM NaCl dramatically improve the stability of the enzyme with over 90% activity remaining after 1 week at 4°C |