天门冬氨酸分子手性转变机理及水分子和羟自由基的催化作用  

Chiral Transformation Mechanism of Aspteine Molecules and Catalytic Action of Water Molecules Hydroxyl Free Radicals

作　　者：刘芳[1] 高峰[1] 闫红彦[1] 马宏源[1] 王佐成[1] 佟华[1] 

机构地区：[1]白城师范学院物理学院,白城137000

出　　处：《复旦学报（自然科学版）》2016年第2期215-222,共8页Journal of Fudan University：Natural Science

基　　金：吉林省科技发展计划项目(20130101131JC)

摘　　要：采用密度泛函理论的B3LYP方法和微扰理论的MP2方法,研究了单体天门冬氨酸分子手性转变机理及水分子和羟自由基对氢迁移反应的催化作用.反应通道研究发现:天门冬氨酸手性转变有a,b,c和d 4个反应通道.a是手性C上的H以氨基N为桥,转移到手性C另一侧;b是手性C上的H顺次以羰基O和氨基N为桥,转移到手性碳另一侧;c是手性C上的H只以羰基O为桥,转移到手性碳另一侧;d是羧基内H迁移后,手性C上的H再以羰基O为桥,转移到手性碳另一侧.势能面计算表明:a通道是优势反应通道,最高能垒为258.2 kJ·mol^(-1),来自手性C上的H向氨基N转移的过渡态;2个水分子构成的链使该能垒降为117.1 kJ·mol^(-1),水分子和羟自由基构成的链使该能垒降为98.6 kJ·mol^(-1).The chiral transformation mechanism of the aspteine monomer and the catalytic effect of water molecules and hydroxyl radicals on the hydrogen transfer reaction were studied based on she B3LYP 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 ehiral transformation reaction. In the channel a, the hydrogen of ehiral carbon used the imino N as a bridge and was transferred to the other side of chiral carbon. In the 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 the 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 the channel d, the hydrogen was firstly transferred in the carbonyl, 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 the channel a was the most dominant reaction channel and the highest energy barrier was 258.2 kJ.mol-1. it came from transition state that H transfer from chiral C to the amino N. Besides, using the chain composed of two water molecules and the chain composed of hydroxyl free radical and one water molecule as the hydrogen migration vector, the high-energy barriers were reduced to 117. 1 kJ.mo1-1 and 98.6 kJ.mol-1 , respectively.

关 键 词：手性 天门冬氨酸 密度泛函理论 过渡态 微扰论 

分 类 号：O641.12[理学—物理化学]