摘要
用酒精沉淀、Sephadex G-100凝胶过滤和离子交换柱层析等步骤对黑曲霉(Aspergillusniger)S4的生淀粉糖化酶进行了分离,纯化出三个电泳纯组分(GⅠ、GⅡ和 GⅢ),纯化倍数分别为5.4、6.0和1.9;酶活收率分别为10.2%、10.7%和1.9%。三个组分均为酸性糖蛋白,其糖含量分别为11.68%、8.6%和3.6%;pI 值分别为4.0、3.9和3.6;分子量分别为138000、62000和57500。通过对这三个组分的性质和它们对生淀粉作用的 V(max)/K_m 值的测定,探讨了生淀粉糖化酶的作用机理。
The enzymes from Aspergillus niger S4 were studed and found that glucoamylase's diges-ting and absorbing activities to raw starches were varied.Three fractions,GⅠ,GⅡ and GⅢ were purified by ethnol precipitation,gel filtration andion exchange chromatography from crude extract of Asp.niger S4.All the purified fractionswere glucoamylase and homogeneous in polyacrylamide gel electrophoresis.To each fraction,the purifications achieved were 5.4,6.0 and 19;the yields of them were 10.2%,10.7% and1.9% respectively.All of them were acidic glycoproteins Their carbohydrate contants were11.68%,8.6% and 3.6%,respectively.The molecular weights of GⅠ,GⅡ and GⅢ were estima-ted to be 138000,62000 and 57500,respectively,by SDS-polyacrylamide gel electrophoresisTheir pI values were 4.0,3.9 and 3.6,respectively.Their active optimum conditions were atpH 4.0—5.0 and 60℃ All these results could roughly explain the different digesting andabsorbing activities of crude extract to raw starches.
出处
《微生物学报》
CAS
CSCD
北大核心
1993年第2期108-114,共7页
Acta Microbiologica Sinica
基金
国家“七五”攻关课题
关键词
黑曲霉
生淀粉糖化酶
Aspergillus niger
Raw-starch--digesting glucoamylase