The complexity of condensed tannin binding to bovine serum albumin--An isothermal titration calorimetry study.

Autor: Kilmister RL; Department of Economic Development, Jobs, Transport and Resources, Victoria, PO Box 905, Mildura, VIC 3502, Australia. Electronic address: rachel.kilmister@ecodev.vic.gov.au., Faulkner P; Department of Economic Development, Jobs, Transport and Resources, Victoria, PO Box 905, Mildura, VIC 3502, Australia., Downey MO; Department of Economic Development, Jobs, Transport and Resources, Victoria, PO Box 905, Mildura, VIC 3502, Australia., Darby SJ; Department of Chemical and Biological Engineering, ChELSI Institute, University of Sheffield, Sheffield S1 3JD, England, United Kingdom., Falconer RJ; Department of Chemical and Biological Engineering, ChELSI Institute, University of Sheffield, Sheffield S1 3JD, England, United Kingdom.
Jazyk: angličtina
Zdroj: Food chemistry [Food Chem] 2016 Jan 01; Vol. 190, pp. 173-178. Date of Electronic Publication: 2015 May 06.
DOI: 10.1016/j.foodchem.2015.04.144
Abstrakt: Isothermal titration calorimetry was applied to study the binding of purified proanthocyanidin oligomers to bovine serum albumin (BSA). The molecular weight of the proanthocyanidin oligomer had a major impact on its binding to BSA. The calculated change in enthalpy (ΔH) and association constant (Ka) became greater as the oligomer size increased then plateaued at the heptameric oligomer. These results support a model for precipitation of proteins by proanthocyanidin where increased oligomer size enhanced the opportunity for cross linkages between proteins ultimately forming sediment-able complexes. The authors suggest tannin binding to proteins is opportunistic and involves multiple sites, each with a different Ka and ΔH of binding. The ΔH of binding comprises both an endothermic hydrophobic interaction and exothermic hydrogen bond component. This suggests the calculated entropy value (ΔS) for tannin-protein interactions is subject to a systematic error and should be interpreted with caution.
(Copyright © 2015 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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