底物中硅原子对苦杏仁醇腈酶催化不对称转氰反应的影响  

Effect of Silicon in Substrate on Transcyanation Catalyzed by Oxynitrilase from Bitter Almond Meal

作　　者：何俊[1] 宗敏华[1] 刘应瑾[1] 张媛媛[1] 吴虹[1] 

机构地区：[1]华南理工大学生物工程系,广东广州510640

出　　处：《催化学报》2005年第4期335-339,共5页

基　　金：国家自然科学基金(20376026);广东省自然科学基金(31349);博士学科点专项科研基金(20030561017)资助项目

摘　　要：对比研究了不同条件下苦杏仁醇腈酶催化乙酰基三甲基硅烷及其碳结构类似物3,3-二甲基2丁酮的转氰反应.结果表明,苦杏仁醇腈酶催化乙酰基三甲基硅烷转氰反应的初速率及对映体选择性均高于其碳结构类似物在同一条件下的对应值.动力学研究结果表明,苦杏仁醇腈酶催化乙酰基三甲基硅烷转氰反应的表观动力学参数为Km=27.12mmol/L和vmax=7.05mmol/(L·h),活化能为51.92kJ/mol.苦杏仁醇腈酶催化3,3二甲基2丁酮转氰反应的表观动力学参数为Km=146.58mmol/L和vmax=2.52mmol/(L·h),活化能为75.04kJ/mol.根据硅原子的特性及酶反应机理合理解释了实验结果.The oxynitrilase from different sources, such as almond seed meal and apple seed meal, was found to be able to catalyze the transcyanation of acetyltrimethylsilane with acetone cyanohydrin (donor of HCN) in an aqueous/organic biphasic system for efficient preparation of 2-trimethylsilyl-2-hydroxyl-proplonitrile, and the acetyltrimethylsilane was a better substrate for the enzymatic transcyanation than its carbon analogue 3, 3dimethyl-2-butanone. To examine the effect of silicon in substrate on the reaction in details, the comparative study on transcyanation of acetyltrimethylsilane and its carbon analogue catalyzed by oxynitrilase from bitter almond meal under different conditions was made. Within the range assayed, the initial reaction rate and the product enantioselectivity for the acetyltrimethylsilane were all much higher than the corresponding values for 3, 3dimethyl-2-butanone under the same conditions. The kinetics study demonstrated that the apparent kinetic parameters for the enzymatic transcyanation of acetyltrimethylsilane were K(m) = 27. 12 mmol/L and v(max) = 7.05 kmmol/(L center dot h) respectively, and its activation energy was 51. 92 kj /mol; the apparent kinetic parameters for the enzymatic transcyanation of 3,3-dimethyl-2-butanone were K(m) =146.58 mmol/L and v(max) = 2.52 mmol/(L center dot h) and its activation energy was 75.04 kJ/mol.

关 键 词：有机硅化合物 苦杏仁 醇腈酶 乙酰基三甲基硅烷 3 3-二甲基-2-丁酮 不对称转氰 

分 类 号：O621.251[理学—有机化学]