摘要
采用硫酸铵高饱和度一步沉淀,Sephadex G-25脱盐,DEAE—Toyopearl离子交换层析,Sepharose S—100 HR凝胶过滤法,从黑曲霉糖化酶粗酶液中纯化出电泳均一的糖化酶。其分子量为73～75Kd,等电点为pH3.3,最适pH为4.2,最适反应温度为60℃,对可溶性淀粉的K_m值为7.56。该糖化酶的含糖量为17.9％,此外还测定了其氨基酸组成及含量。
The glucoamylase was isolated from the gross enzyme solution of Aspergillus niger by high saturation of ammonium sulfate precipitation, was desalted by Sephadex G-25, DEAE-Toyopearl column chromatography and Sepharose S—100 HR gel filtration. The glucoamylase showed only one band in Disc polyacrylamide electrophoresis. The molecular weight of glucoamylase obtained was 73～75Kd, its isoelectric point was pH 3.3, the optimum pH was 4.0, the optimum temperature was 60℃. The K_m and V_(max) for soluble starch was 2.54g/L and 7.55, respectively. The content of neutral carbonhydrate of this glucoamylase was 17.9％. In addition,, the amino acid composition of glucoamylase was determined.
出处
《河北省科学院学报》
CAS
1992年第1期57-64,共8页
Journal of The Hebei Academy of Sciences
