半胱氨酸分子手性转变及水分子的催化机理  

Chiral Transformation of Cysteine Molecules and Catalytic Mechanism of Water Molecules

作　　者：王佐成[1] 范志琳 程彦明[3] 梅泽民[4] 

机构地区：[1]白城师范学院物理学院,吉林白城137000 [2]辽宁师范大学化学与材料学院,辽宁大连116000 [3]长春理工大学光电信息学院,吉林长春130000 [4]白城师范学院化学学院,吉林白城137000

出　　处：《武汉大学学报（理学版）》2016年第4期368-374,共7页Journal of Wuhan University:Natural Science Edition

基　　金：吉林省科技发展计划资助项目(20130101131JC)

摘　　要：采用密度泛函理论的B3LYP方法和微扰理论的MP2方法研究了单体半胱氨酸分子手性转变机理及水分子对氢迁移反应的催化作用.根据研究结果,半胱氨酸分子手性转变反应有4个通道:a通道是手性C上的H只以氨基N为桥转移至手性C另一侧;b通道是手性C上的H依次以羰基O和氨基N为桥转移至手性碳另一侧;c通道是手性C上的H只以羰基O为桥转移至手性碳另一侧;d通道是手性C上的H以羟基O为桥转移至手性碳另一侧.势能面计算表明:a通道为优势反应通道,最高能垒254.6kJ·mol^(-1);1个水分子及2个水分子构成的链作为H迁移媒介,使最高能垒降至163.2和126.2kJ·mol^(-1),说明水分子对H迁移反应具有较好的催化作用.The chiral transformation mechanism of the cysteine monomer and the catalytic effect of water molecules and hydroxyl radicals on the hydrogen transfer reaction were studied based on the B3 LYP methods of density functional theory and the MP2 methods of perturbation theory.The study of reaction channel showed that there were four channels a,b,c and d in the chiral transformation reaction.In channel a,the hydrogen of chiral carbon used the imino N as a bridge and was transferred to the other side of chiral carbon.In channel b,the hydrogen of chiral carbon successively used the carbonyl O and imino N as a bridge and was transferred to the other side of chiral carbon.In channel c,the hydrogen of chiral carbon used the carbonyl O as a bridge and was transferred to the other side of chiral carbon.In channel d,the hydrogen was firstly transferred in the carbonyl,and then the hydrogen of chiral carbon used the carbonyl O as a bridge and was transferred to the other side of chiral carbon.Calculation of potential energy surface showed that channel a was the most dominant reaction channel with the highest energy barrier of 254.6kJ·mol^-1.By using the chain composed of one and two water molecules as the hydrogen migration vector,the high-energy barriers were respectively reduced to 163.2kJ·mol^-1 and 126.2kJ·mol^-1.The results suggest that water molecules had a better catalysis for hydrogen migration.

关 键 词：手性 半胱氨酸 密度泛函理论 过渡态 微扰理论 

分 类 号：O641.12[理学—物理化学]