黑曲霉M89菊粉酶的提纯与性质

黑曲霉(Aspergillusniger）M89菊粉酶经硫酸铵分级盐析、SephadexG-200凝胶过滤、DEAE-纤维素离子交换层析、聚丙烯酞胺凝胶电泳（PAGE）制备分离，提纯到4个菊粉酶组分EⅠ、EⅡ、EⅢ和EⅣ。用SDS-PAGE测定分子量分别为102．6、97．9、61．2和36．5kD;用等电聚焦电泳测得其等电点分别为4．15、4．24、4．48和4．15。4个组分的最适反应温度均为55～60℃；EⅠ的最适pH为pH4．0，其余3个组分为pH4．5．各组分的热稳定性有一定差异，分子量越小的组分，热稳定性越好，55℃处理90min，EⅠ有一定的热失活，其余3个组分无活力丧失，4个组分都是外切酶。

PURIFICATION AND PROPERTIES OF INULINASES FROM ASPERGILLUS NIGER M89

Four inulinase components were purified from Aspergillus niger M89 by (NH4)2SO4 fractionation, Sephadex G-200 gel filtration, DEAE-cellulose chromatography and polyacrylamide gel electrophoresis (PAGE). The molecular weight of EI EII EIII and EIV were indicated to be 102.6, 97.9, 62.5 and 36.5 kD respectively by SDS-PAGE. Measured by isoeleetric focusing, their isoelectric points were 4.15, 4.24, 4.48 and 4.15 respectively. Four forms of inulinase exibited maximal inulinase activity between 55-60 degrees C with optimal pH 4.0-5.0. There were some difference in their thermal stability. The little the molecule of the component was, the stronger its thermal stability was. All of four components were exo-acting inulinases.