摘要
在B3LYP/6-31G**的计算水平上,研究了鸟嘌呤在一分子和两分子水参与下水化去氨基反应的机理.结果表明:鸟嘌呤不管是与一分子水还是两分子水的水化去氨基反应,都是分两步进行的.首先,发生水解反应生成四配位的中间体,这一步为速控步;接着,发生分子内的氢迁移并脱去氨基生成终产物黄嘌呤.鸟嘌呤在两分子水的作用下发生的去氨基反应,其中一分子水起催化剂的作用.溶剂化效应(B3LYP/6-31G**)计算结果说明,溶剂化效应并不改变反应的进程,只降低反应过程的活化位垒.鸟嘌呤在一分子或两分子水参与下,其水化去氨基反应的速控步活化位垒比较高,在动力学上难以进行.
The hydrolytic deamination reaction mechanism of guanine（ G） and nH_2O（ n = 1、2） have been theoretically investigated including solvent effects at the B3 LYP /6-31G＊＊levels. The results showed that the hydrolytic deamination reaction of G may proceed two steps. The first step was rate-controlling,and the second step belonged to an internal hydrogen transfer reaction. The study of the potential energy surface showed that the deamination reaction of G-n H_2O did not took place because of a higher barrier for the rate-controlling,which was agreement with the experimental result. In addition,one water molecule acted as catalyst for the deaminaiton reaction of G and 2H_2O.
出处
《信阳师范学院学报（自然科学版）》
CAS
北大核心
2016年第2期189-192,共4页
Journal of Xinyang Normal University(Natural Science Edition)
基金
上海市科学技术委员会项目(14500503300)
