[Objective] The research aimed to study the secreted expression of S-edenosyl-L-methionine synthetase （SAMS） in Pichia pastoris. Method ] The gene coding SAMS, from the genomic DNA of Saccharomyces cerevisiae, was ...[Objective] The research aimed to study the secreted expression of S-edenosyl-L-methionine synthetase （SAMS） in Pichia pastoris. Method ] The gene coding SAMS, from the genomic DNA of Saccharomyces cerevisiae, was amplified by PCR and inserted into the secreted expression vector pPIC9K to get recombinant plasmid. The recombinant plasmid pPIC9K-sarr~ was integrated into Pichia pastoris GSl15 genome by electroporation and induced by methanol. The activity of the recombinant enzyme was measured using high-pedormance liquid chroma- tography （HPLC） by determining the production of S-adenosy-L-methionine （SAM） with the enzyme secreted. [ ResultJ The molecular weight of the expression protein identified by SDS-PAGE was about 50 kD, being larger than the theoretical molecular mass of SAMS, which might be due to the glycosytation in the process of secretion. Methanol-induction as well as preliminary purification could enhance the enzyme activity, espe- cially the latter, after which the specific activity of SAMS was improved to 61.48 U/rng. [Conclusion] SAMS with biological activity was secreted successfully in Pichia pastoris GSl15 for the first time. And it is the start for the genetic engineering strains to open up prospects for industrial production.展开更多
可计算一般均衡模型(Computable General Equilibrium,CGE)是经济学的重要研究方法之一,近年来被广泛应用在关税、贸易壁垒、资源与环境等领域。本文基于投入产出理论,将我国41个产业部门与土地利用现状分类一级分类中5种国有建设用地...可计算一般均衡模型(Computable General Equilibrium,CGE)是经济学的重要研究方法之一,近年来被广泛应用在关税、贸易壁垒、资源与环境等领域。本文基于投入产出理论,将我国41个产业部门与土地利用现状分类一级分类中5种国有建设用地相对应。根据最新的投入产出表,结合《中国国土资源年鉴》、《北京市统计年鉴》、《上海市统计年鉴》、《天津市统计年鉴》、《重庆市统计年鉴》等相关数据编制了2012-2015年北京、上海、天津、重庆四个直辖市的社会核算矩阵(SAM),并且根据直接交叉熵法进行了平衡。本数据集对构建城市用地CGE模型,研究城市用地及城市经济学相关问题能提供数据支持。展开更多
文摘[Objective] The research aimed to study the secreted expression of S-edenosyl-L-methionine synthetase （SAMS） in Pichia pastoris. Method ] The gene coding SAMS, from the genomic DNA of Saccharomyces cerevisiae, was amplified by PCR and inserted into the secreted expression vector pPIC9K to get recombinant plasmid. The recombinant plasmid pPIC9K-sarr~ was integrated into Pichia pastoris GSl15 genome by electroporation and induced by methanol. The activity of the recombinant enzyme was measured using high-pedormance liquid chroma- tography （HPLC） by determining the production of S-adenosy-L-methionine （SAM） with the enzyme secreted. [ ResultJ The molecular weight of the expression protein identified by SDS-PAGE was about 50 kD, being larger than the theoretical molecular mass of SAMS, which might be due to the glycosytation in the process of secretion. Methanol-induction as well as preliminary purification could enhance the enzyme activity, espe- cially the latter, after which the specific activity of SAMS was improved to 61.48 U/rng. [Conclusion] SAMS with biological activity was secreted successfully in Pichia pastoris GSl15 for the first time. And it is the start for the genetic engineering strains to open up prospects for industrial production.
文摘可计算一般均衡模型(Computable General Equilibrium,CGE)是经济学的重要研究方法之一,近年来被广泛应用在关税、贸易壁垒、资源与环境等领域。本文基于投入产出理论,将我国41个产业部门与土地利用现状分类一级分类中5种国有建设用地相对应。根据最新的投入产出表,结合《中国国土资源年鉴》、《北京市统计年鉴》、《上海市统计年鉴》、《天津市统计年鉴》、《重庆市统计年鉴》等相关数据编制了2012-2015年北京、上海、天津、重庆四个直辖市的社会核算矩阵(SAM),并且根据直接交叉熵法进行了平衡。本数据集对构建城市用地CGE模型,研究城市用地及城市经济学相关问题能提供数据支持。
