Computational quantitation of the aldehyde forms of aldohexoses and disaccharides composed of d-glucose: Predictions of their reactivities in the Maillard reaction

Abstract

The aldehyde forms of saccharides are the major reactants in the Maillard reaction of sugars with the free amine groups of proteins. The ratios of the aldehyde forms of saccharides in aqueous solutions are crucial to rate determining of the Maillard reaction. The aldehyde ratios of disaccharides and oligosaccharides have been barely analyzed experimentally or computationally. Here, we tested the feasibility of the quantum chemical calculation with various calculation levels and aqueous solution models to predict the aldehyde ratios of disaccharides comprising d-glucose. The aldehyde ratio of the d-glucose calculated employing the CAM-B3LYP/6–311+G(2d,2p) level of theory and the solute electron density (SMD) solvent model closely consisted with the experimental data. Additionally, the aldehyde ratios of disaccharides correlated with the oxime formation tendency investigated with Nα-(aminooxyacetyl)tryptophanylarginine amide. This prediction method could be applied to the quantitation of the aldehyde forms of oligosaccharides, as well as the design of saccharide-based drugs.