Study of soluble expression in Escherichia coli of α-cyclodextrin glycosyl transferase produced by Paenibacillus macerans and properties of its derivatives
通过设计简并引物,从Paenibacillus macerans YLW菌株中克隆到其α-环糊精葡萄糖基转移酶(α-CGTase)基因,构建重组质粒α-CGTase-p ET28a(+),转化大肠杆菌BL21(DE3),得到重组菌株α-CGTase-p ET28a/BL21(DE3)。在16℃,1m M IPTG条件下诱导15 h,实现了α-CGTase的可溶性表达,胞内酶活达到10046U/m L,是野生菌株胞外酶活的3.25倍。经镍柱一步法亲和纯化α-CGTase后,酶蛋白纯化了6.05倍,酶收率28.82%,通过SDS-PAGE检测获得表观电泳纯酶蛋白。酶催化转化实验表明:重组α-CGTase酶转化质量分数为5%的马铃薯淀粉15 h后,环糊精的总转化率可达40.7%,转化生成α-CD,β-CD,γ-CD比例分别为:43.6%、41.8%和14.6%。该重组酶对α-CD具有较好的转化专一性,通过转化条件的进一步优化将具有非常好的产业化开发前景。
【英文摘要】
The gene encoding α-cyclodextrin glycosyltransferase(α-CGTase)was amplified by degenerate primer from Paenibacillus macerans YLW and was inserted into expression vector p ET28a(+),and a recombinant strain α-CGTasep ET28a/BL21(DE3)was constructed. After induction for 15 h at 16℃ with 1 m M IPTG,α-CGTase was expressed in solution and the activity of α-CGTase in the periplasm was reached to 10046 U/m L,which was approximately 3.25-fold with that from the parent strain. The recombinant α-CGTase was purified by ...
【基金】
陕西省科学院应用基础研究项目(2013K-09);陕西省科学院科学技术平台项目(2015k-33)
【更新日期】
2017-03-29
【分类号】
TQ925
【正文快照】
China Food Additives试验研究环糊精葡萄糖基转移酶(简称CGTase,EC2.4.1.19)是α-淀粉酶家族的重要成员,其主要作用是通过环化反应催化淀粉、糖原等葡萄糖聚合物生成环糊精(简称CD)[1]。根据葡萄糖残基数的不同,可将环糊精分为α-CD(6个),β-CD(7个)、γ-CD(8个)以及更大环的?