嗜热脂肪芽孢杆菌普鲁兰酶酶学性质研究

摘要

对获得的嗜热脂肪芽孢杆菌普鲁兰酶进行了酶学性质测定.结果表明：普鲁兰酶最适温度为60℃,此温度下处理90 min,残存酶活在70%以上,70℃酶的半衰期大于50 min；最适pH 5.6,在pH 4.5~6.0的范围50℃保温24 h仍具有较高活性；Km为0.036μmol/L,Vmax为20.16μmol/min；Mn2+、Mg2+和 Ca2+对酶有激活作用,其中以Mn2+的激活作用最强,而Cu2+和Zn2+则有抑制作用.研究表明嗜热脂肪芽孢杆菌普鲁兰酶是高温酸性酶,对底物有较强亲合力和催化活性,在淀粉糖化工业中有良好的应用前景.%A study was conducted on the enzymatic properties of pullulanase which obtained from Ba-cillus stearothermophilus.The results showed that the optimum temperature was 60 ℃,about 70% of re-sidual activity was still sustained after treatment for 90 min at 60 ℃.The half-life was longer than 50 min at 70 ℃.Optimum pH was 5.6.The enzyme kept a higher activity in the range of pH 4.5 to 6.0 for 24 h at 50 ℃.Km was 0.036μmol/L,Vmax was 20.16μmol/min;Mn2+,Mg2+ and Ca2+ activated the enzyme activi-ty,among them Mn2+ had the most activation.Cu2+ and Zn2+ inhibited the enzyme activity.It is suggested that the pullulanase obtained from B.stearothermophilus belongs to high-temperature acidic enzymes,can be used in starch processing industry.