Feddaoui W, Aschi A, Bey H, Othman T. Study of the complex coacervation mechanism between ovalbumin and the strong polyanion PSSNa: influence of temperature and pH.
EUROPEAN BIOPHYSICS JOURNAL : EBJ 2019;
48:803-811. [PMID:
31655892 DOI:
10.1007/s00249-019-01406-y]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 09/10/2019] [Accepted: 10/13/2019] [Indexed: 01/18/2023]
Abstract
We studied the complex between ovalbumin and long flexible poly-(sodium 4-styrene sulfonate) as a function of pH and temperature. We used various techniques [turbidimetry, conductometry, dynamic light scattering, viscosimetry, and ultra-small-angle light scattering (USALS)] to fully characterize the coacervate complex. Different phases of complexation versus temperature were determined by turbidimetric analysis (pHc, pHϕ1, and pHϕ2). The optimal protein/polyelectrolyte interaction occurred at pHopt 4. An increase in temperature made the hydrophobic interactions more favorable in the case of the soluble complex and complex coacervation phases (pH > pHϕ2). We systematically determined the activation energy to follow the conformational changes of the complex at different temperatures. At pHopt, the size of the formed complex showed a remarkable decrease with temperature increase. USALS was used to determine simultaneously the radius of gyration (Rg) and fractal dimension Df of the coacervate.
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