Optimizing the Properties of Tyrosine and It's Oxidation Derivatives Based on Quantum Computation

Using the quantum mechanic procedure with the DFT/BLYP method, the structures and properties of tyrosine (Tyr) and its oxidation derivatives (DOPA and DOPA-Quinone) were theoretically investigated. For these three molecules, geometry optimizations, electric charges distribution at the atomic level, thermodynamic parameters and frontier orbital energies were obtained. Compared with DOPA-Quinone, Tyr and DOPA have higher chemical reactivities and tend to participate in the electrophilic substitution reaction. Moreover, the thermodynamic calculations show that no matter at the low, normal or high temperature, the oxidation reactions of Tyr and DOPA are exothermic, and their ∆ G are always less than 0, suggesting that these two compounds are easily oxidized. Finally, the calculation of frontier orbital energies indicates that the stability of Tyr is similar to that of DOPA, and among the three, DOPA-Quinone is the most stable one.