Structural correlations of complexation of apple pectin with imidazole and L-histidine methyl ester

Abstract

The thermodynamic and structural study of the complex formation of apple pectin with structural analogs of histidine (imidazole and its methyl ester) was carried out using spectral methods. The composition, stability constants of the complexes, and standard thermodynamic characteristics (Δ G° , Δ H° , Δ S° ) of the complex formation process were determined. The decisive contribution of the imidazole fragment of the amino acid to the stability of the pectin-histidine complex is shown. The esterification of the carboxyl group of histidine, its conversion into methyl ester, has an insignificant effect on the efficiency of complex formation with pectin, leading only to a slight increase in binding.