【摘要】 以α -单硬脂酸甘油酯为底物研究油包水 (W /O)微乳液介质中脂肪酶的水解催化活性 .结果表明 ,由AOT/水 /正庚烷构成的ω/O微乳液体系的w0 值、pH值、缓冲液离子浓度、AOT浓度等参数对脂肪酶催化活性有影响 ,最佳酶活力对应的微乳液组成为 :w0 =8;pH =7.17( 67mmol/L的KH2 PO4 -Na2 HPO4 缓冲液 ) ;[AOT]=0 .10mol/L .研究还表明 ,微乳液介质中 ,脂肪酶催化α -单硬脂酸甘油酯水解反应动力学与水介质中相类似 ;当酶浓度恒定时 ,反应速率与底物浓度的关系符合Michaelis -Menten方程 ,最大反应速率υmax(用脂肪酶活力表示 )约为 15 6u ,米氏常数Km 约为5 .6mmol/L ;当底物浓度恒定时 ,反应速率与酶浓度成正比 .更多还原

【Abstract】 The lipase-catalyzed hydrolytic reaction of glycerol α-monostearate as substrate in a water-in-oil (W/O) microemulsion was first studied. Results indicated that, for a W/O microemulsion composed of n-heptane, water and sodium bis (2-ethylhexyl) sulfosuccinate (AOT), the pH value and the ionic strength of the phosphate buffer, the ω 0 value and the AOT concentration had an effect on the activity of lipase. The optimum values of these parameters were as follows: 1) the pH value was 7.17 with the concentration of the phosphate buffer being 0.067 mol/L; 2) the ω 0 value was 8;and 3) the concentration of AOT was 0.10 mol/L. Kinetic studies showed that the reaction mechanism in the microemulsion was the same as that in water. At a constant concentration of lipase, the relationship between the reaction rate and the concentration of the substrate could be expressed as Michaelis-Menten equation. The maximum rate and the Michaelis constant were about 156u (expressed as the activity of lipase) and 5.6 mmol/L, respectively. At a constant concentration of substrate, the rate was directly proportional to the concentration of lipase.更多还原