酵母催化2-辛酮不对称还原反应特性与醇脱氢酶基因表达水平的关联性研究

Association of Yeast Catalyzed Asymmetric Reduction of 2-Octanone and the Expression Level of Alcohol Dehydrogenase Gene

研究通过介质工程,选择4种Log P值(分配系数的对数值)的有机溶剂,采用气相色谱技术检测有机溶剂对酿酒酵母催化2-辛酮不对称还原反应的催化活性与反应选择性的影响,并通过荧光定量PCR(RT-PCR)检测不同水/有机溶剂两相体系下YADH1与YADH2基因表达情况,旨在探究不同水/有机溶剂两相体系与酿酒酵母催化2-辛酮不对称还原反应特性的关系,并考察其反应特性与YADH基因的表达水平之间是否存在关联,试图从基因表达水平解释不同有机介质中酵母催化羰基不对称还原特性的内在机制,从而为获得重要手性中间体(S)-2-辛醇产物提供理论指导。分析结果表明,不同水/有机溶剂两相体系对酿酒酵母催化2-辛酮羰基不对称还原反应的催化活性与反应选择性有较大影响,其中,催化活性在水/有机溶剂两相体系比单水相体系降低,但反应选择性却有较大提高(甲苯除外),而且log P值(分配系数的对数值)越大,产物对映体过量(Enantiomeric excess,e.e)值也越大。进一步研究表明,YADH基因表达水平与酵母羰基不对称还原反应特性有重要关联,YADH基因表达水平与酵母催化活性呈正相关,但与反应选择性呈负相关。

The author chose four organic solvents with different Log P values（ distribution coefficient of value） for this research,and used gas chromatography technique to explore the correlation between asymmetric reduction of 2-octanone of saccharomyces cerevisiae and organic solven. They chose real-time PCR（ RT-PCR） to detect YADH1,YADH2 gene expression under different water/organic solvents two-phase system. Their purpose is to explore the relationship between different water/organic solvents two-phase system and to saccharomyces cerevisiae catalytic 2-octanone asymmetric reduction reaction characteristics,and to study whether there is a correlation between the expression level of YADH gene and reaction characteristics. Finally,they tried to explain the intrinsic mechanism in the level of gene expression,thus providing theoretical guidance to obtain important chiral intermediates（ S）-2-octanol products.Analysis results show that different water/organic solvents two-phase system has a great influence on saccharomyces cerevisiae catalytic asymmetric 2-octanone carbonyl reduction reaction. The catalytic activity in water/organic solvent two-phase system is reduced than single water phase system,but the reaction selectivity has increased greatly（ except toluene）,and the bigger the log P value,the greater the product enantiomeric excess（ enantiomeric excess,e. e） value. Further research shows that YADH gene expression level is related to yeast carbonyl reduction reaction characteristics,YADH gene expression level was positively correlated with the catalytic activity of yeast,but negatively correlated with the reaction selectivity.