5-甲基胞嘧啶水解反应机理的理论研究  

Theoretical Study on the Hydrolysis Reaction Mechanism of 5-methylcytosine

作　　者：张爱华[1] 杨宝华[1] 李琳[1] 

机构地区：[1]首都医科大学燕京医学院,北京顺义101300

出　　处：《信阳师范学院学报（自然科学版）》2014年第3期341-343,共3页Journal of Xinyang Normal University(Natural Science Edition)

基　　金：首都医科大学科研启动基金项目(1300-1300171010)

摘　　要：采用密度泛函理论方法,在B3LYP/6-31G**水平下研究了5-甲基胞嘧啶(m5C)水解反应的微观机理和势能剖面.计算结果表明,5-甲基胞嘧啶的水解反应有两条反应途径:(A)水分子进攻m5C生成中间体IM1,然后氨分子充当桥生成终产物胸腺嘧啶;(B)水分子进攻m5C首先生成四配位的中间体IM2,然后中间体分解成终产物胸腺嘧啶和氨分子.能量计算结果表明,5-甲基胞嘧啶的水解反应决速步的活化能垒较高,在自发状态下,5-甲基胞嘧啶的水解反应难于进行.The hydrolysis reaction mechanism and potential energy surface of 5-methylcytosine （ m5 C） were inves- tigated using density functional theory （DFT） at the B3LYP/6-31 G ＊ ＊ level. The results show that the hydrolysis reaction of m5 C includes two pathways： （A）With the water attacking at m5 C, thymine is formed; （B） This pathway is as- sociated with a tetracoordinated intermediate formed and decomposed. Because the hydrolysis reaction of m5 C has a higher barrier, the hydrolysis reaction of m5 C does not take place for the opening system, which is agreement with the experimental result. The present calculations have rationalized and verified all the possible reaction channels.

关 键 词：5-甲基胞嘧啶 水解反应 胸腺嘧啶 

分 类 号：O64[理学—物理化学]