2.7.4.8 -10°C, more than a month 2.7.4.8 -15°C, more than 6 months 2.7.4.8 -20°C, stable at all stages of purification 2.7.4.8 -20°C, stable for several months after purification by Blue Sepharose and gel filtration 2.7.4.8 -25°C, stable 2.7.4.8 -30°C, in N-ethylmorpholine-HCl buffer, pH 7.5, several years 2.7.4.8 0-4°C, 6-10 weeks 2.7.4.8 0°C, below, in 70% saturated ammonium sulfate, several years 2.7.4.8 4°C, at pH-values below 4 or above 9, inactivation within 48 h 2.7.4.8 4°C, calf thymus enzyme, stable in the absence of thiols