2.3.1.54 -20°C, 10 mM MOPS-KOH, pH 7.0, 50 mM KCl, thiols, EDTA in 50% ethyleneglycol, proved stable for months 2.3.1.54 -20°C, stable for at least several months 2.3.1.54 4°C, 50 mM potassium phosphate buffer, containing 1 mM dithiothreitol, storage of the purified enzyme in an anaerobic glove box for 2 weeks reduces activity by 50%