果聚糖蔗糖酶基因的克隆表达及酶学性质分析

Gene Cloning，Heterologous Expression and Characterization of Levansucrase fromBacillus amyloliquefaciens

DOI：10.3969/j.issn.1673-1689.2019.03.018

中文关键词: 果聚糖蔗糖酶 解淀粉芽孢杆菌 重组表达 性质

英文关键词: levansucrase,Bacillus amyloliquefaciens,recombinant expression,characterization

基金项目:

摘要点击次数: 143

全文下载次数: 250

中文摘要:

将来源于解淀粉芽孢杆菌（Bacillus amyloliquefaciens）的果聚糖蔗糖酶（levansucrase）基因进行克隆，并将其在Escherichia coli BL21（DE3）中表达。对发酵产酶后的菌体进行破壁和离心，粗酶液经镍柱纯化后，进行酶学性质研究。结果表明，重组酶的水解酶活和转移酶活最适温度分别为45 ℃和40 ℃，最适pH分别为6.5和6.0。此外，果聚糖蔗糖酶的Km和Vmax分别为150.74 mmol/L和21.23 μmol/（mL·min）。最后，在pH 6.0、40 ℃条件下，果聚糖蔗糖酶催化反应12 h后，体系中果聚糖质量分数可达34.05%。

英文摘要:

Levansucrase fromBacillus amyloliquefacienswas cloned and heterologously expressed inEscherichia coliBL21（DE3）. After purification，the enzymatic characterization of levansucrase was determined and analyzed. The optimum temperature of hydrolytic activity was 45 ℃ and the maximal transfructosylation activity was measured at 40 ℃. The optimum pH for hydrolytic and transfructosylation activities were 6.5 and 6.0，respectively. TheKm andVmax values for levansucrase were calculated to be 150.74 mmol/L sucrose and 21.23 μmol/（mL·min），respectively. Levansucrase-catalyzed reaction was investigated at pH 6.0 and 40 ℃. The result indicated that the content of levan was up to 34.05% in total products after 12 h.

查看全文 查看/发表评论 下载PDF阅读器