Four strains of microorganisms which have activity of chloroacetophenone reduction were screened, in which Saccharomyces cerevisiae B5 showed the highest activity and good stereoselectivity. This strains showed differ...Four strains of microorganisms which have activity of chloroacetophenone reduction were screened, in which Saccharomyces cerevisiae B5 showed the highest activity and good stereoselectivity. This strains showed different activity on the reduction of various substrates in the following order: 2′-chloroacetophenone > 2-chloromethylacetophenone > 4′-chloroacetophenone > 3′-chloroacetophenone > acetophenone. Ethanol is the best cosubstrate and its optimal concentration is 5%.展开更多
The bifunctional fusion protein systems consisting of Rhodococcus erythropolis chiral alcohol dehydrogenase(READH),Candida boidinii formate dehydrogenase(CbFDH) or maltose binding protein(MBP) were constructed to rege...The bifunctional fusion protein systems consisting of Rhodococcus erythropolis chiral alcohol dehydrogenase(READH),Candida boidinii formate dehydrogenase(CbFDH) or maltose binding protein(MBP) were constructed to regenerate the cofactors for biocatalysis.READH originated from Rhodococcus erythropolis is an(S)-specific nicotinamide adenine dinucleotide(NADH)-dependent alcohol dehydrogenase,meanwhile,CbFDH originated from Candida boidinii is an NADH-dependent formate dehydrogenase.The strategies of the different fusion protein systems included:(1) fusion of the N terminus of READH to the C terminus of MBP,(2) fusion of the N terminus of CbFDH to the C terminus of MBP,(3) fusion of the N terminus of READH to the C terminus of CbFDH,(4) fusion of the C terminus of READH to the N terminus of CbFDH.The activities of READHs were depressed in all fusion strategies.When the N terminus of READH was fused to the C terminus of CbFDH,READH reached the highest activity,but CbFDH had no activity.In contrast,when the C terminus of READH was fused to the N terminus of CbFDH,CbFDH showed the highest activity,and both moieties displayed activities.From this study,the authors suggest that the rational design of the bifunctional fusion protein system may improve the biocatalysis efficiency by the simultaneous cofactor regeneration.展开更多
为开发新型手性铝锂试剂,探讨双不对称诱导效应,选用含杂原子的光学活性氨基醇为辅助配体,与1,2,5,6 二丙酮甘露醇共同修饰LiAlH4,对潜手性芳酮进行不对称还原,得到光学活性醇;通过与α D 乙酰氧基 L 丙酰氯生成非对映异构体酯,经气相...为开发新型手性铝锂试剂,探讨双不对称诱导效应,选用含杂原子的光学活性氨基醇为辅助配体,与1,2,5,6 二丙酮甘露醇共同修饰LiAlH4,对潜手性芳酮进行不对称还原,得到光学活性醇;通过与α D 乙酰氧基 L 丙酰氯生成非对映异构体酯,经气相色谱分析,对映体过量在43 6%～77 7%之间。结果表明辅助配体的绝对构型、空间位阻、β位杂原子对光学产率均有影响。展开更多
文摘Four strains of microorganisms which have activity of chloroacetophenone reduction were screened, in which Saccharomyces cerevisiae B5 showed the highest activity and good stereoselectivity. This strains showed different activity on the reduction of various substrates in the following order: 2′-chloroacetophenone > 2-chloromethylacetophenone > 4′-chloroacetophenone > 3′-chloroacetophenone > acetophenone. Ethanol is the best cosubstrate and its optimal concentration is 5%.
文摘The bifunctional fusion protein systems consisting of Rhodococcus erythropolis chiral alcohol dehydrogenase(READH),Candida boidinii formate dehydrogenase(CbFDH) or maltose binding protein(MBP) were constructed to regenerate the cofactors for biocatalysis.READH originated from Rhodococcus erythropolis is an(S)-specific nicotinamide adenine dinucleotide(NADH)-dependent alcohol dehydrogenase,meanwhile,CbFDH originated from Candida boidinii is an NADH-dependent formate dehydrogenase.The strategies of the different fusion protein systems included:(1) fusion of the N terminus of READH to the C terminus of MBP,(2) fusion of the N terminus of CbFDH to the C terminus of MBP,(3) fusion of the N terminus of READH to the C terminus of CbFDH,(4) fusion of the C terminus of READH to the N terminus of CbFDH.The activities of READHs were depressed in all fusion strategies.When the N terminus of READH was fused to the C terminus of CbFDH,READH reached the highest activity,but CbFDH had no activity.In contrast,when the C terminus of READH was fused to the N terminus of CbFDH,CbFDH showed the highest activity,and both moieties displayed activities.From this study,the authors suggest that the rational design of the bifunctional fusion protein system may improve the biocatalysis efficiency by the simultaneous cofactor regeneration.
文摘为开发新型手性铝锂试剂,探讨双不对称诱导效应,选用含杂原子的光学活性氨基醇为辅助配体,与1,2,5,6 二丙酮甘露醇共同修饰LiAlH4,对潜手性芳酮进行不对称还原,得到光学活性醇;通过与α D 乙酰氧基 L 丙酰氯生成非对映异构体酯,经气相色谱分析,对映体过量在43 6%～77 7%之间。结果表明辅助配体的绝对构型、空间位阻、β位杂原子对光学产率均有影响。
