环糊精葡萄糖基转移酶分离纯化及酶学性质研究

通过筛选和诱变获得一株高产环糊精葡萄糖基转移酶芽孢杆菌菌株，研究该菌所产环糊精葡萄糖基转移酶的分离纯化及酶学性质，结果显示：发酵液经离心处理后，采用硫酸铵溶液分步盐析、DEAE-cellulose 52 离子交换层析、Sephadex G-200 凝胶过滤层析方法得到电泳级环糊精葡萄糖基转移酶，SDS-PAGE 电泳显示该酶分子量为33kD，纯化倍数为10，得率为14.4%。该酶反应的最适温度为50℃，在40～60℃基本稳定，最适pH 值为8.0，在pH6.0～10.0 范围内基本稳定。Fe2+、Cu2+、Mg2+ 对该酶活力有明显的抑制作用。

Isolation,Purification and Enzymatic Characteristics of Cyclodextrin Glucanotransferase

The yclodextrin glucanotransferase (CGTase) produced by a high-yield CGTase-producing stain of Bacillus that isolated from soil was isolated from the fermentation broth of this strain by ammonium sulphate fractional salting out and then sequentially purified by DEAE-cellulose DE-52 ion exchange chromatography and Sephadex G-200 gel filtration chromatography. The SDS-PAGE analysis indicated that the CGTase obtained by the above procedures was of electrophoresis grade, and its molecular weight was 33 kD. The purification multiple and the recovery rate were 10 and 14.4 %, respectively. The optimum reaction temperature of the CGTase was 50 ℃, and this enzyme was stable in the range of 40-60 ℃. Its optimum reaction pH was 8.0, and it was stable in the range of pH 6.0 -10.0. The enzyme activity was strongly inhibited by Fe2+, Cu2+ and Mg2+.