Calcium binding to amino acids. Inspirations for design of calcium peptide chelates with high bioavailability

This study explores the effects of pH and temperature on calcium binding to 20 amino acids common in proteins, providing insights into calcium peptide chelate development as food supplements. Electrochemical measurements and density functional theory calculations revealed that calcium binding constants increase with pH, especially in alkaline conditions. For intestine pH, Asp and Glu showed the strongest binding assigned to their side chain carboxylic groups. At the same time, Arg and Lys exhibited weaker binding due to side chain amino groups being positively charged. Binding constants were more temperature-sensitive for Asp and Glu, increasing with temperature decrease. Molecular docking simulations indicated that calcium complexation enhances the targeting and binding stability of amino acids to TRPV6, the calcium channel in the intestine. These findings highlight the importance of both the intrinsic calcium binding ability of amino acids and their interaction with TRPV6, providing a scientific basis for the development of calcium supplements with high bioavailability.