%0 Journal Article
%T 耐热木聚糖酶基因xyn11EM在大肠杆菌中的表达
%A 何瑶
%A 殷欣
%A 吴芹
%A 邬敏辰
%J 食品与生物技术学报
%D 2016
%R 10.3979//j.issn.1673-1689.2016.09.006
%X 将人工合成经密码子优化的11家族耐热木聚糖酶基因xyn11EM克隆至表达质粒pET-28a（+）中，获得重组质粒pET-28a-xyn11EM。将其转化Escherichia coli BL21（DE3），构建表达耐热木聚糖酶的重组工程菌E. coli BL21/xyn11EM。用IPTG诱导表达重组木聚糖酶Xyn11EM（reXyn11EM），酶活性可达47.5 U/mL。SDS-PAGE分析显示，reXyn11EM的表观相对分子质量为24 800。reXyn11EM的最适反应温度为70 ℃，在70 ℃以下稳定。最适反应pH为6.5~7.0，在pH 5.0~8.0范围内稳定。大多数金属离子和EDTA对该重组酶的活性影响不大。reXyn11EM的Km和Vmax值分别为7.2 mg/mL和54.7 U/mg。结果表明xyn11EM成功在E. coli 中实现了异源表达，其良好的热稳定性具有较好的工业应用潜力。</br>A codon-optimized gene（named xyn11EM），which encodes a thermotolerant xylanase belonging to the glycoside hydrolase family 11，was synthesized，and cloned into the expression plasmid pET-28a（+）. The recombinant Escherichia coli（designated E. coli BL21/xyn11EM），expressing the thermostable xylanase，was constructed by transforming the recombinant plasmid，pET-28a-xyn11EM，into E. coli BL21（DE3）. The recombinant E. coli BL21/xyn11EM was induced with IPTG to express reXyn11EM. The reXyn11EM activity reached 47.5 U/mL. The apparent molecular weight of reXyn11EM was estimated to be 24 800 by SDS-PAGE analysis. Its optimal temperature and pH were 70 ℃ and 7.0，respectively. It was stable at a temperature of 70 ℃ or below，and at a pH range of 5.0~8.0. Its activity was not significantly affected by most of metal ions tested and EDTA. The Km and Vmax of reXyn11EM toward birchwood xylan were 7.2 mg/mL and 54.7 U/mg. The excellent thermostability of reXyn11EM make it has great potential in industrial application
%K 耐热木聚糖酶 大肠杆菌 表达 酶学性质&lt
%K /br&gt
%K thermostable xylanase
%K Escherichia coli
%K expression
%K enzymatic characterization
%U http://spyswjs.cnjournals.com/spyswjs/ch/reader/view_abstract.aspx?file_no=201609006&flag=1