Theoretical Investigation Of The Chiral Transition Of Alpha-Alanine Cu2+ Complex In Water Solution

The chiral transition of S-alpha-alanine Cu2+ complex (S-A) in water solution was investigated by density functional theory combined with SMD solvation model. In principle, the chiral transition of S-A could be realized via the following four pathways: carbonyl oxygen as the bridge, carbonyl oxygen and amino nitrogen as the bridge, amino nitrogen as the bridge and Cu as the bridge. The potential energy surface calculation shows that under the effect of implicit solvent, the reaction channel with Cu as the bridge is the most dominant, and the energy barrier of the rate-determining steps is 103.3 kJ mol(-1). The subdominant channel of hydrogen migration is the bridge channel of amino nitrogen, and the energy barrier of the rate-determining steps is 183.5 kJ mol(-1). The remaining two channels are inferior channels. Under the explicit solvent effect, the channel with amino-nitrogen as the bridge is the most advantageous, and the energy barrier of the rate-determining steps is reduced to 138.0 kJ mol(-1). The subdominant channel for hydrogen migration is Cu, and the energy barrier of the rate-determining steps increases to 145.3 kJ mol(-1). The remaining two channels are inferior channels. The results show that S-A complex can better maintain its chiral characteristics in water solution, and the divalent copper salt of alpha-alanine is safe to supplement Cu2+ and alanine in living bodies.