摘要
从黑曲霉cDNA文库中筛选出糖化酶基因,并在酿酒酵母中进行表达.阳性克隆在发酵培养基中培养60h后,产生的糖化酶酶活力达到峰值为4.3U/mL.测定结果显示其糖化酶大小为1 908bp,编码636个氨基酸残基组成的蛋白质.酶学性质分析显示该酶的最适反应温度为50℃,pH为5.0.经柱分离纯化其发酵上清液后,SDS-PAGE电泳方法,测得它的分子量大约为70kD,且条带清晰.
An expression cDNA library was constructed from aspergillus niger, then glucoamylase gene was isolated and efficiently expressed in S. cerevisiae. The results showed that the maximum activity of glucoamylase was 4.2 U/mL when cultivated for 60 h. Sequence analysis revealed that glucoamylase had 1 908 bp,which encodes a putative polypeptide of 636 amino acids. The enzyme proerties showed that the optimum pH and temperature was 5.0 and 50 ℃, the expressed protein was purified from the fermented supernatant using DEAE clumon and determined by SDS-PAGE. The results of SDS-PAGE also showed that the molecular weights of the enzyme was 70 kDa.
出处
《安徽工程大学学报》
CAS
2012年第2期1-3,7,共4页
Journal of Anhui Polytechnic University
关键词
黑曲霉
糖化酶
酿酒酵母
表达
aspergilus niger
glucoamylase
S. cerevisiae
expression
