根霉葡萄糖淀粉酶的简易纯化法及部分理化性质

A SIMPLE PURIFIED METHOD AND SOME PHYSICO-CHEMICAL PROPERTIES OF GLUCOAMYLASE PRODUCED BY RHIZOPUS SP.

从汾酒大曲中分离到一株根霉,经诱变处理后获得了具有高产葡萄糖淀粉酶的变异株。将此菌株用固体麸曲培养,水抽提得原酶液。经 DEAE-Sephadex A-50、Sephadex G-100和CM-Cellulose C52三步柱层析后,得到了紫外光谱和 SDS-聚丙烯酰胺凝胶电泳皆为均一的葡萄糖淀粉酶。总活力回收达70%左右,比活力提高23.70倍。该酶的 A_(280nm)~1%=14.70,经SDS-聚丙烯酰胺凝胶电泳和凝胶过滤层析表明其分子量约为78400,酶分子中赖氨酸含量较高,属典型的根霉型葡萄糖淀粉酶。

An electrophoretic homogeneous prepara-tion of glucoamylase produced by Rhizopussp.was obtained with only three steps columnchromatography.The strain mutated was ahigh glucoamylase-producing one.After ex-tracting the solid bran with water,the ex-tract free from bran was supplied to DEAE-Sephadex A-50 column.Then the part con-taining glucoamylase activity was packed toSephadex G-100 column and the fraction ofglucoamylase was rechromatographed on CM-Cellulose C52 at last.through the three stepsas mentioned above,a quite pure enzyme pre-paration was detected with both UV-spectraand electrophoresis.The molecular weightof the enzyme was about 78400 determined bySDS-PAGE and gel filtration respectively.The amino acid analysis showed that the en-zyme had more quantity of lysine residues.It is estimated that the enzyme belongs to thetypical Rhizopus-type glucoamylase as repor-ted in references.