气相环境下Na+催化丙氨酸分子手性转变的机理  

Mechanism of Chiral Transition of Alanine Catalyzed by Na^+ in Gas Phase

作　　者：李冰[1] 陈静思 徐锐英 潘宇[4] 刘芳[4] 杨晓翠[4] 王佐成[4] LI Bing;CHEN Jingsi;Xü Ruiying;PAN Yu;LIU Fang;YANG Xiaocui;WANG Zuocheng(College of Mechanical Engineering,Baicheng Normal University,Baicheng Jilin 137000,China;Department of Clinical Medicine,Baicheng Medical College,Baicheng Jilin 137000,China;Communication College,Baicheng Normal University,Baicheng Jilin 137000,China;College of Physics,Baicheng Normal University,Baicheng Jilin 137000,China)

机构地区：[1]白城师范学院机械工程学院,吉林白城137000 [2]白城医学高等专科学校临床医学系,吉林白城137000 [3]白城师范学院传媒学院,吉林白城137000 [4]白城师范学院物理学院,吉林白城137000

出　　处：《复旦学报（自然科学版）》2020年第4期495-504,共10页Journal of Fudan University：Natural Science

基　　金：吉林省科技发展计划自然科学基金(20130101308JC,20160101308JC);吉林省教育厅科学研究规划项目(JJKH20200002KJ)。

摘　　要：采用密度泛函理论的M06方法研究了Na+催化丙氨酸(Ala)分子的手性对映体转变.反应通道研究发现:Ala1(Ala的稳定构型1)的手性转变有a、b、c和d 4个通道,a通道是羧羟基氢迁移后α-氢以羰基氧为桥迁移,b通道是羧羟基氢迁移后α-氢向羰基氧迁移再接质子从质子化氨基向α-碳迁移,c和d通道是α-氢分别以氨基氮和羰基氧为桥迁移.Ala2(Ala的稳定构型2)的手性转变有2个通道a和b,a通道是α-氢只以羰基氧为桥迁移,b通道是α-氢迁移到羰基氧后氨基上的质子再向α-碳迁移.势能面计算结果表明:Ala1手性转变的a和b通道具有优势,反应的总包能垒(反应活化能)是125.4kJ·mol^-1.Ala2手性转变的a通道具有优势,反应的总包能垒(反应活化能)是200.0kJ·mol^-1.结果表明:气相环境下Na+的催化可显著地降低Ala实现手性转变的能垒.The title reaction has been studied using the M06 method based on density functional theory.The study of reaction pathways shows that the Ala1 chiral transition has four pathways a,b,c and d.In pathway a,α-H is transferred using carbonyl O atom as a bridge after the transition of carboxy hydroxy hydrogen.In pathway b,α-H is transferred to carbonyl O atom after the transition of carboxy hydroxy hydrogen and then proton transfers from protonated amino group toα-C.α-H is transferred with amino N atom and carbonyl O atom as a bridge in pathway c and d,respectively.The Ala2 chiral transition has two pathways a and b.α-H is transferred using carbonyl O atom as a bridge only in pathway a.The proton on the amino group is transferred toα-C afterα-H is transferred to carbonyl O atom in pathway b.The potential energy surface calculation shows that the dominant pathways of the Ala1 chiral transition are pathway a and b,and the total energy barrier of the reaction is 125.4 kJ·mol^-1.The dominant pathway of the Ala2 chiral transition is pathway a,and the total energy barrier of the reaction is 200.0 kJ·mol^-1.The results show that the catalysis of sodium ion in the gas phase can significantly reduce the energy barrier of Ala to achieve chiral transition.

关 键 词：丙氨酸 钠离子 手性转变 密度泛函理论 过渡态 能垒 

分 类 号：O641.12[理学—物理化学]