关键词: 密度泛函理论, 天冬酰胺, 过渡态, 手性

Abstract: Using density functional theory B3LYP, we investigated the second reaction channel process of the chiral transition of the nonrestricted area monomer asparagine (Asn) molecule at the level of 6-311-+G(2-df-) basis sets. We drawed a complete chiral transition path reaction potential energy surface by finding structures of the extreme value points including the transition states and intermediates, and analyzed the geometric and electronic structure properties of extreme value points. The results show that the 4H atom on the chiral carbon atom of SAsn molecule can transfer to the other side of the carbon atom via the 10O atom of carboxyl atoms as a bridge, and achieve the chiral transition of Asn molecule from Stype to Rtype. On this path there are two transition states and three intermediates. The maximum reaction energy barrier is 313.222 1 kJ/mol.

Key words: transition state, asparagine, chirality, density functional theory