3.4.21.7	-20°C to -30°C, pH 9.0, Tris-Lys-NaCl-EDTA buffer containing 25% glycerol, stable	
3.4.21.7	20°C, enzyme in raw milk, 10 days, the enzyme keeps a relatively constant level of activity	
3.4.21.7	37°C, enzyme in milk products, 16 days, enzyme activity is decreased	
3.4.21.7	4-37°C, isolated plasmin in NaCl solution, enzyme activity is lost