Title

Electrostatic Interaction and Complex Formation between Gum Arabic and Bovine Serum Albumin

Comments

Only metadata available from this website. This article was published in the Journal of the Biomacromolecules in 2010 by the American Chemical Society. Copyright © American Chemical Society. To access the final edited and published work, see http://www.rsc.org

Abstract

The interaction of gum arabic (GA) and bovine serum albumin (BSA) has been investigated through turbidity and light scattering intensity measurements and by the use of dynamic light scattering, laser Doppler velocimetry, and isothermal titration calorimetry. It has been shown that GA and BSA can form soluble and insoluble complexes depending on the solution pH and the mixing ratio and is a function of the net charge on the complex. Soluble complexes were obtained when the electrophoretic mobility was greater than ±1. 5 μm s−1 V−1 cm−1. Changes in the value of the isoelectric point of the complexes with mixing ratio and isothermal titration calorimetric data indicated that complexes formed at pHs 3 and 4 consisted of 60 BSA molecules for every GA molecule, while at pH 5 there were 10 BSA molecules per GA molecule. Calorimetric studies also indicated that the interaction occurred in two stages at both pH 3 and pH 4, but that the nature of the interaction at these two pH values was significantly different. This was attributed to differences in the relative magnitude of the positive and negative charges on the BSA and GA, respectively, and possibly due to changes in the BSA conformation. The fact that there is an interaction at pH 5, which is above the isoelectric point of the BSA, is due to the interaction of the carboxylate groups on the GA with positive patches on the BSA or to the charge regulation of the protein−polysaccharide system brought about by changes in dissociation equilibria. Complexation is reduced as the ionic strength of the solvent increases and is prevented at a NaCl concentration of 120 mM.

Disciplines

Macromolecular Substances | Materials Chemistry | Natural Products Chemistry and Pharmacognosy | Pharmaceutics and Drug Design | Polymer Chemistry

Recommended Citation

Vinayahan, T., Williams, P.A., and Phillips, G.O. (2010) ‘Electrostatic Interaction and Complex Formation between Gum Arabic and Bovine Serum Albumin’. Biomacromolecules, 11 (12), 3367–3374


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