Microemulsion System, Yeast Alcohol Dehydrogenase Reduction Preparation Of (s) -1 - Phenylsulfonyl -2 - Propanol, And Reaction Mechanism

(S)-1-Phenylsulfonyl-2-Propanol has been synthesized in AOT/Tween(60) /water/ Hexamethylene microemulsion system by high active baker's yeast in this paper. The impact of reaction time, concentration of substrate, yeast volume, carbon sources volume, carbon sources type, surface active agent usage, water content and the type solvents for reaction rates have been investigated by orthogonal experiment. The optimum reaction conditions were 4 hour, substrate concentrations 0.007g/mL, yeast consumption 0.18 g/mL, carbon sources of glucose consumption 0.05 g/mL, surface active agent AOT (0.04 g/mL) and Tween60 (0.04 g/mL) usage rate of 2:1, 0.08 mL/mL of water in system and solvents of hexamethylene. Moreover, the impact of concentration of substrate, yeast volume, reaction time, water content, carbon sources volume for reaction rates and enantiomer excess value also have been studied under the optimum reaction conditions. The results were fully in consistent with the conclusions of the orthogonal experimental. In response to the best conditions, the reaction rate achieved 98.5% and the enantiomer excess value achieved 100%. For the presence of surface active agent, the degree of decentralization of yeast in system increased. The permeability of yeast cell wall was thus raised. Compared to other methods, in our reaction conditions the response time was shortened significantly and objects concentrations increased in the same yeast usage conditions.The kinetics of the asymmetric synthesis of (S)-1-Phenylsulfonyl- 2-Propanol have been studied in determining the best reaction conditions. The Michaelis constants were obtained by determining the initial reaction rate with different concentrations of the s. The results were 0.000675 g/mL for 0.004168g/mL and 0.01799g/mL for microaqueous hexamethylene system at 35℃.The mechanism of the asymmetric reduction reaction of yeast alcohol dehydrogenase reducing (S)-l-Phenylsulfonyl-2-Propanol have been investigated by the quantum chemistry program package of Gaussian03. The hydride and proton transfer process also have been explored and found the possible reaction pathway. To confirm the connection of the transition state with designated intermediates, intrinsic reaction coordinate calculations were also performed. The major changes of the charge of the distribution of atomic in proton transfer process were analysed. The effect of induced-fit of enzyme to substrate was proved by contrasting the structure change of the composite of substrate and enzymes before and after.