Comparative studies on thermodynamic characteristics of pea legumin and legumin-T thermal denaturation

• Published in: International journal of biological macromolecules 2001-12, Vol.29 (4), p.225-236
• Main Authors: Kozhevnikov, G.O, Danilenko, A.N, Braudo, E.E, Schwenke, K.D
• Format: Article
• Language: English
• Subjects: Calorimetry; Calorimetry, Differential Scanning; Hot Temperature; Legumin-T; Legumins; Pea legumin; Pisum sativum; Plant Proteins - chemistry; Protein Binding; Protein Denaturation; Protein Folding; Protein Structure, Tertiary; Sodium Chloride - pharmacology; Temperature; Thermal denaturation; Thermodynamics
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/S0141-8130(01)00173-8

Characteristics of thermal denaturation of pea legumin and a product of its limited proteolysis with trypsin – legumin-T, in a wide range of NaCl concentrations have bean measured by means of differential scanning microcalorimetry. By the increase of NaCl concentration, the number of cooperative units (domains) increases from 1 per one polypeptide chain to 2 for legumin and 1.8 for legumin-T. Deconvolution of denaturation peaks have revealed up to three peaks, which were ascribed to the dissociation of protein macromolecules to subunits and the unfolding of α- and β-polypeptide chains. The analysis of experimental data based on some assumptions showed that the splitting of C-termini of α-chains, which are not constituents of cooperative domains, in the course of limited trypsinolysis results in destabilization of the quaternary structure of legumin and loosening of α-chains, as well as decrease of the temperatures of their maximum stability.