【目的】通过表达多种重组立体选择性氧化还原酶,分析其催化不对称还原N,N-二甲基-3-酮-3-(2-噻吩)-1-丙胺(DKTP)的性质,从而构建酶促合成(S)-N,N-二甲基-3-羟基-3-(2-噻吩)-1-丙胺(DHTP)的反应体系。【方法】基于已有立体选择性氧化还...【目的】通过表达多种重组立体选择性氧化还原酶,分析其催化不对称还原N,N-二甲基-3-酮-3-(2-噻吩)-1-丙胺(DKTP)的性质,从而构建酶促合成(S)-N,N-二甲基-3-羟基-3-(2-噻吩)-1-丙胺(DHTP)的反应体系。【方法】基于已有立体选择性氧化还原酶重组大肠杆菌,通过Ni离子亲和层析法纯化得到重组氧化还原酶,以DKTP为底物,考察不同重组氧化还原酶对DKTP的催化活性和选择性,进一步对高选择性酶促合成(S)-DHTP的重组酶CR2进行性质分析,并考察其在最适条件下不对称还原DKTP的过程。【结果】筛选获得产物构型为(S)-型的催化活性最高的酶为CR2,该酶米氏常数Km为0.135 mmol/L,kcat/Km为3.689 L/(mmol·s),最适p H 8.4(0.1 mol/L三乙醇胺缓冲液),最适反应温度为35°C,在10-45°C条件下和p H 7.5-8.5较为稳定,Zn2+离子对酶活有促进作用。CR2催化DKTP不对称还原反应6 h后,DHTP的产率达92.1%、光学纯度达99.9%。【结论】基于活性和选择性分析,获得不对称还原DKTP的目标酶CR2,其催化特性有利于高立体选择性还原DKTP生成度洛西汀中间体(S)-DHTP,从而为进一步提高酶促不对称还原DKTP的转化效率提供研究基础。展开更多
In this article, AHPS (3 - allyloxy- 2 -hydrory- 1 -Propanesulfonate salt) wassynthesized to use in emulsifier-Ne emulsion polymerization of BA/BMa/MMA systemfor high solid content latexes. Storage stability klow beha...In this article, AHPS (3 - allyloxy- 2 -hydrory- 1 -Propanesulfonate salt) wassynthesized to use in emulsifier-Ne emulsion polymerization of BA/BMa/MMA systemfor high solid content latexes. Storage stability klow behavior of the latexes,morphology of the obtained latex particles, dynamic viscoelastic behavior, tensilestrength and water resistance properties of the resulted copolymers were investigated.The experimental results show that with the addition of AHPS, stability of the emulsionis greatly improved that there appears no apparent precipitation dunring thepolymerization and storage at room temperature for 6 months and at -10℃ for fourmonths. Flow of the latexes follows the Bingham body laws, diameter of the latexparticles is about 0.6μn, of which is larger than that of by conventional emulsionpolymerization(0.12μm). In addition, not only water resistance of the copolymersobtained by emulsifier-free emulsion polymerization is greatly improved, but alsotensile strength is obviously enhanced.展开更多
文摘【目的】通过表达多种重组立体选择性氧化还原酶,分析其催化不对称还原N,N-二甲基-3-酮-3-(2-噻吩)-1-丙胺(DKTP)的性质,从而构建酶促合成(S)-N,N-二甲基-3-羟基-3-(2-噻吩)-1-丙胺(DHTP)的反应体系。【方法】基于已有立体选择性氧化还原酶重组大肠杆菌,通过Ni离子亲和层析法纯化得到重组氧化还原酶,以DKTP为底物,考察不同重组氧化还原酶对DKTP的催化活性和选择性,进一步对高选择性酶促合成(S)-DHTP的重组酶CR2进行性质分析,并考察其在最适条件下不对称还原DKTP的过程。【结果】筛选获得产物构型为(S)-型的催化活性最高的酶为CR2,该酶米氏常数Km为0.135 mmol/L,kcat/Km为3.689 L/(mmol·s),最适p H 8.4(0.1 mol/L三乙醇胺缓冲液),最适反应温度为35°C,在10-45°C条件下和p H 7.5-8.5较为稳定,Zn2+离子对酶活有促进作用。CR2催化DKTP不对称还原反应6 h后,DHTP的产率达92.1%、光学纯度达99.9%。【结论】基于活性和选择性分析,获得不对称还原DKTP的目标酶CR2,其催化特性有利于高立体选择性还原DKTP生成度洛西汀中间体(S)-DHTP,从而为进一步提高酶促不对称还原DKTP的转化效率提供研究基础。
文摘In this article, AHPS (3 - allyloxy- 2 -hydrory- 1 -Propanesulfonate salt) wassynthesized to use in emulsifier-Ne emulsion polymerization of BA/BMa/MMA systemfor high solid content latexes. Storage stability klow behavior of the latexes,morphology of the obtained latex particles, dynamic viscoelastic behavior, tensilestrength and water resistance properties of the resulted copolymers were investigated.The experimental results show that with the addition of AHPS, stability of the emulsionis greatly improved that there appears no apparent precipitation dunring thepolymerization and storage at room temperature for 6 months and at -10℃ for fourmonths. Flow of the latexes follows the Bingham body laws, diameter of the latexparticles is about 0.6μn, of which is larger than that of by conventional emulsionpolymerization(0.12μm). In addition, not only water resistance of the copolymersobtained by emulsifier-free emulsion polymerization is greatly improved, but alsotensile strength is obviously enhanced.
