关键词: 缬氨酸, 二价镁, 配合物, 溶剂效应, 密度泛函理论, 对映异构, 自由能垒

Abstract: The enantiomerism transformation mechanism of bivalent magnesium valine complexes (Val·Mg²⁺) in physiological environment was studied by using M06-2X and MN15 hybrid exchange functional methods for dealing with remote weak interactions of density functional theory and SMD model method (for solvent effects). The results of the study on enantiomerism reaction channels show that there are three enantiomerism reaction channels of chiral Val·Mg²⁺, which are H proton uses carbonyl O as a bridge,  carbonyl O combined with amino N as a bridge,  and amino N as a bridge alone. The calculation of free energy potential energy surface of the reaction process shows that it is advantageous for H proton using amino N as a bridge alone for migration reaction. Under the polarity of the water solvent, the energy barrier for speed control step of the dominant reaction channel is 210.4 kJ/mol,  and the catalysis of water molecules (clusters) reduces the energy barrier to 116.1—118.3 kJ/mol. The  enantiomization rate of bivalent magnesium valine complexes in the aqueous liquid phase is extremely slow,  and it can be  safely  used to complement bivalent magnesium ions and valine in living organisms.

Key words: valine,  , bivalent magnesium,  , complex,  , solvent effect,  , density functional theory,  , enantiomerism,  , free energy barrier