中文摘要：

目的：构建L-蛋氨酸γ-裂解酶（Metase）基因的两种高效原核表达载体，建立最佳高效原核表达体系。方法：在Metase基因已经克隆的基础上，通过分子克隆技术构建两种重组表达质粒pBV220-Metase和pGEX-4T-1-Metase,重组质粒转化感受态大肠杆菌Dh5α,诱导表达，测定Metase活性，统计分析比较。结果：成功构建出两种高效重组表达质粒pBV220-Metase和pGEX-4T-1-Metase,经诱导后都能测出Metase活性。结果：重组表达质粒pBV220-Metase具有比pGEX-4T-1-Metase更强的活性，可作为Metase的高效表达体系。

英文摘要：

To construct two highly efficient prokaryotic expression vectors of L-methionine γ-lyase genes,and to establish the best efficient prokaryotic expression system.Methods：On the basis of Metase gene has been cloned,two types of recombinant plasmids pBV220-Metase and pGEX-4T-1-Metase were established by molecular cloning techniques,and then the recombinant plasmids were transformed into E.coli Dh5α which were induced and expressed.Next,Metase activity was measured.Statistical analysis and comparison were carried out.Results：Two types of highly efficient recombinant expression plasmids pBV220-Metase and pGEX-4T-1-Metase were constructed successfully;Metase activity can be measured after the induction.Conclusion：Recombinant expression plasmid pBV220-Metase had higher activity than pGEX-4T-1-Metase,and pBV-220 may be determined to be the best natural Metase efficient expression system.