Estimation of the racemization rate constants for α-amino acids using Density Functional Theory

• Published in: Computational and theoretical chemistry 2017-03, Vol.1104, p.43-46
• Main Authors: Zeng, Yue, Zhang, Baoman, Wang, Meiya
• Format: Article
• Language: English
• Subjects: Density functional theory; Racemization; Rate constant; α-Amino acids
• ISSN: 2210-271X
• DOI: 10.1016/j.comptc.2017.01.034

An efficient and reliable protocol is presented to estimate the racemization rate constants (krac) of α-amino acids using density functional theory (DFT). The calculation results show that the data estimated by our approach gives a fairly good fit with the experimental results. [Display omitted] •The dynamic property (krac) can be rapidly and reliably predicted by the thermodynamic property (ΔG).•The maximum deviation is 0.601 log(krac) unit and the standard deviation is 0.267 log(krac) unit, respectively, for 21 α-amino acids.•The calculation accuracy is similar when using RGC(g) or RGC(aq). This research shows that the Gibbs free energy, which is calculated by Density Functional Theory (DFT), largely deviates from the experimental value, but is proportional to the experimental value. Moreover, the slope and intercept are equivalent between molecules within the same class, such as α-amino acids. Based on this conclusion an efficient and reliable protocol is presented to estimate the racemization rate constants (krac) of α-amino acids using DFT at the level of B3LYP/6-311G(d,p). The polarizable continuum model (PCM) is used to describe solvation when the calculation is completed in aqueous solution. In this way, 21 racemization rate constants (krac) are reproduced with the maximum deviation of 0.601 log(krac) unit, and the standard deviation of 0.267 log(krac) unit. The calculation results indicate that the data estimated by this approach gives a fairly good fit with the experimental results.