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设计合成6种采用不同1,3-二丁基咪唑阳离子和六氟磷酸(PF6-)或双三氟甲烷磺酰亚胺(TFSI-)阴离子的离子液体.以脂肪酶催化拆分1-苯乙醇为模型反应,分别考察介质、水含量和温度对反应的影响.结果表明,在1,3-二异丁基咪唑六氟磷酸盐([D(i-C4)Im][PF6])离子液体介质中酶的活性和反应性明显高于其它离子液体和正己烷.因此,[D(i-C4)Im][PF6]被确定为反应介质.在最佳条件下,初始反应速率是1.93μmol?mg-1?min-1,1-苯乙醇的转化率达50%,对映体过量值eep>99%,酶的半衰期为348h,酶重复使用10次后活性没有明显减少.此外,圆二色谱、内源荧光光谱和光学显微镜研究表明,酶在[D(i-C4)Im][PF6]中保温6d后氨基酸残基的裸露程度略有增加,但其二级结构仍保持稳定,且以天然的折叠球形态存在.
Six kinds of ionic liquids with different 1,3-dibutylimidazolium cation and hexafluorophosphate (PF6-) or bistrifluoromethanesulfonimide (TFSI-) anions were designed and synthesized.The lipase-catalyzed resolution of 1-benzene Ethanol as the model reaction, the effects of medium, water content and temperature on the reaction were investigated respectively.The results showed that the reaction of 1,3-diisobutylimidazolium hexafluorophosphate ([D (i-C4) Im] [PF6] The activity and reactivity of the enzyme in the liquid medium was significantly higher than that of the other ionic liquids and n-hexane, and therefore [D (i-C4) Im] [PF6] was identified as the reaction medium.Under the optimum conditions, the initial reaction rate was 1.93 The conversion rate of enantiomeric excess was 99%, the half-life of the enzyme was 348h, and the activity was not significantly reduced after the enzyme was repeatedly used for 10 times. In addition, Circular dichroism spectroscopy, endogenous fluorescence spectroscopy and optical microscopy showed that the degree of exposure of amino acid residues slightly increased after incubation of [D (i-C4) Im] [PF6] for 6 days, but the secondary structure remained stable , And exists as a natural folded ball.