Structural Features of the Apple Pectin Complex Formation with Imidazole and L-Histidine Methyl Ester

摘要

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 (ΔG°, ΔH°, and ΔS°) of the complex formation process were determined. The dominating 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 and its conversion into methyl ester influence only slightly the efficiency of complex formation with pectin, leading to a slight increase in binding.