水溶剂环境下两性苯丙氨酸分子对映异构的密度泛函理论研究  

Density Function Theoretical Study on the Enantiomerization of Amphoteric Phenylalanine Molecule in Water-Liquid Phase Environment

作　　者：徐春雪[1] 杨应[1] 张希花[1] 刘军[1] 王佐成[1] 赵丽红[2] 杨晓翠[1] XU Chunxue;YANG Ying;ZHANG Xihua;LIU Jun;WANG Zuocheng;ZHAO Lihong;YANG Xiaocui(Theoretical Computing Center,Baicheng Normal University,Baicheng Jilin 137000,China;College of Pharmacy,Baicheng Medical College,Baicheng Jilin 137000,China)

机构地区：[1]白城师范学院理论计算中心,吉林白城137000 [2]白城医学高等专科学校药学院,吉林白城137000

出　　处：《复旦学报（自然科学版）》2023年第4期486-495,506,共11页Journal of Fudan University：Natural Science

基　　金：吉林省自然科学基金(20160101308C),白城医学高等专科学校科研平台重点项目(BYKPT202207);白城医学高等专科学校高层次人才团队建设项目(BCYZ20220408)。

摘　　要：采用密度泛函理论的M06-2X和MN15方法,结合自洽反应场理论的SMD模型方法,研究了水液相下两性苯丙氨酸(Phe)分子的对映异构。考察了α-H直接以羰基O为桥、Phe分子从两性异构成中性后α-H再以羰基O和氨基N分别为桥向α-C迁移的3个反应通道。势能面研究表明:隐性溶剂效应下第1和第3个反应通道具有优势,决速步自由能垒分别是239.9和236.1 kJ·mol^(-1);显性溶剂效应使第1通道的决速步自由能垒降到142.8 kJ·mol^(-1),第3通道的决速步自由能垒降到120.9 kJ·mol^(-1)。结果表明,水溶剂环境下光学纯的Phe只能少量消旋,生命体补充Phe具有较好的安全性。The enantiomeric isomerization of an amphoteric Phe molecule in the aqueous-liquid phase was studied by using the Density functional theory M06-2X and MN15 methods combined with the SMD model based on the self-consistent reaction field theory.It was found that the title reaction can be carried out in three channels:α-H bridged directly by carbonyl O,and the transition of Phe molecule from amphoteric isomerism to neutralα-H bridged by carbonyl O and Amino N,respectively.The calculation of the potential energy surface shows that the first and third reaction channels have advantages under the effect of the recessive solvent,and the barrier of decision-speed step is 239.9 kJ·mol^(-1)and 236.1 kJ·mol^(-1),respectively;Under the dominant solvent effect,the barrier energy of the first channel is reduced to 142.8 kJ·mol^(-1),and the barrier energy of the third channel is reduced to 120.9 kJ·mol^(-1).The results show that the optical pure Phe can only be racemized in a small amount in an aqueous environment,and the life supplement of Phe is safe.

关 键 词：苯丙氨酸 对映异构 密度泛函理论 过渡态 能垒 

分 类 号：O641.12[理学—物理化学]