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用量子化学从头算与PM3相结合的方法对叶酸辅酶模型——2-甲基-1-乙酰基咪唑啉盐向邻苯二胺转移一碳单元的反应进行了理论研究.结果表明,由于咪唑啉环有两种开环方式,反应可以通过两条互相竞争的途径完成,得到相同的产物.每一条途径都经历了6个反应步骤,包括两种反应物的结合,质子转移,五元环的断裂,苯并咪唑衍生物的形成,再次质子转移和最终产物的生成.上述反应的每一条途径中,两次质子转移过渡态的能量较高,说明该反应存在一般酸碱催化作用,与酶催化甲酸氧化态一碳单元转移的实验结果一致.
Quantum Chemistry ab initio combined with PM3 on the folic acid coenzyme model - 2-methyl-1-acetyl imidazolinium salt to o-phenylenediamine one carbon unit transfer reaction was studied. The results show that, due to imidazole There are two ring-opening modes for the ring, and the reaction can be completed in two competing routes to obtain the same product, each of which undergoes six reaction steps, including the binding of the two reactants, the proton transfer, the five-membered ring The formation of benzimidazole derivatives, the re-proton transfer and the final product formation.In each of the above reactions, the higher the energy of the two proton transfer transition states, indicating that the reaction has the general acid-base catalysis, and The experimental results of enzymatic catalysis of formic acid oxidation state-carbon unit transfer are consistent.