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Mechanism of Chiral Enantiomer Transition ofAsp Molecule and Catalysis of Water
QIAO Chaoyang, ZHUANG Yan, JIANG Chunxu, GAO Feng, YANG Xiaocui, WANG Zuocheng
Journal of Jilin University Science Edition. 2019, 57 (04):
962-972.
Using the dispersion correction density functional WB97XD method, the MP2 method of perturbation theory and the SMD model method of selfconsistent reaction field, we studied the chiral enantiomer transition of two aspartic acid (Asp) molecule in dominant reaction channels, the catalysis and the solvent effect of water molecules. The results show that the chiral enantiomer transition is realized by a series of Asp transition states of the rotation of αcarboxyhydroxyl, βcarboxyhydroxyl, βcarboxyl and Rgroup and proton transport from αcarbon to amino nitrogen, from amino nitrogen to αcarbon and in carboxyl groups, and several kinds of optical isomerism products with different configurations are obtained. The intrinsic energy barriers of Asp molecules with two strong single hydrogen bonds and two moderate strength single hydrogen bonds in the dominant channel are 2585, 2538 kJ/mol, respectively, which are derived from the transition states of transfer of αhydrogen to aminonitrogen, and that are reduced to 133.3, 134.3 kJ/mol by the catalysis of two water clusters, and to 106.3, 107.8 kJ/mol in water solvent environment, respectively.
Therefore, the chiral enantiomer transition of Asp molecules can be realized slowly by the catalysis of water molecular clusters, and the reaction rate can be accelerated by the water solvent effect.
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