荧光假单胞菌天冬氨酸转氨酶的基因克隆及其在大肠杆菌中的表达

采用克隆基因测序技术，从荧光假单胞菌GcM5-1A基因组文库中筛选到了天冬氨酸转氨酶的编码基因aspC。通过聚合酶链式反应（PCR）扩增目的基因，插入pET-15b构建重组表达质粒pET-15bAAT，转化E.coli BL21(DE3)，IPTG诱导天冬氨酸转氨酶在大肠杆菌中高效表达，利用亲和层析法初步分离纯化了重组蛋白。生物活性分析表明，纯化的重组天门冬氨酸转氨酶具有氨基转移活性。

Cloning and Expression of Aspartate Aminotransferase from Pseudomonas fluorescens in Escherichia coli

The gene aspC encoding aspartate aminotransferase was cloned from the library of Pseudomonas fluorescens GcM5-1A by sequencing clones. This gene was amplified by PCR, and cloned into the expression plasmid pET-15b to construct the expressing vector pET-15bAAT. The recombinant plasmid was transformed into E.coli BL21(DE3) to construct engineering bacterium. Recombinant aspartate aminotransferase was overexpressed by IPTG induction and purified by affinity chromatography. Bioassay analyzing results showed that recombinant protein could catalyze the transfer of the amino group.