Статья

Size and Molecular Flexibility Affect the Binding of Ellagitannins to Bovine Serum Albumin

Marina A. DobrevaSchool of Agriculture, Policy and Development, University of Reading, Earley Gate, P.O. Box 236, Reading RG6 6AT, United KingdomRebecca J. GreenSchool of Chemistry, Food and Pharmacy, University of Reading, Whiteknights, P.O. Box 224, Reading RG6 6AP, United KingdomI. Mueller‐HarveySchool of Agriculture, Policy and Development, University of Reading, Earley Gate, P.O. Box 236, Reading RG6 6AT, United KingdomJuha‐Pekka SalminenDepartment of Chemistry, University of Turku, Vatselankatu 2, Turun Yliopisto, Turku FI-20014, FinlandBrendan J. HowlinChemistry Department, FEPS, University of Surrey, Guildford, Surrey GU2 7XH, United KigndomRichard A. FrazierSchool of Chemistry, Food and Pharmacy, University of Reading, Whiteknights, P.O. Box 224, Reading RG6 6AP, United Kingdom

2014en

ABI

Аннотация

Binding to bovine serum albumin of monomeric (vescalagin and pedunculagin) and dimeric ellagitannins (roburin A, oenothein B, and gemin A) was investigated by isothermal titration calorimetry and fluorescence spectroscopy, which indicated two types of binding sites. Stronger and more specific sites exhibited affinity constants, K1, of 10(4)-10(6) M(-1) and stoichiometries, n1, of 2-13 and dominated at low tannin concentrations. Weaker and less-specific binding sites had K2 constants of 10(3)-10(5) M(-1) and stoichiometries, n2, of 16-30 and dominated at higher tannin concentrations. Binding to stronger sites appeared to be dependent on tannin flexibility and the presence of free galloyl groups. Positive entropies for all but gemin A indicated that hydrophobic interactions dominated during complexation. This was supported by an exponential relationship between the affinity, K1, and the modeled hydrophobic accessible surface area and by a linear relationship between K1 and the Stern-Volmer quenching constant, K(SV).

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Идентификаторы

DOI: 10.1021/jf502174r

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