Effect of the Helix-Coil Transition in Bovine Skin Gelatin on Its Associative Phase Separation with Lysozyme
| Autor: | Alexander Volodine, Irina L. Zhuravleva, Ruth Cardinaels, Yurij A. Antonov, Paula Moldenaers |
|---|---|
| Přispěvatelé: | Processing and Performance |
| Rok vydání: | 2017 |
| Předmět: |
Phase transition
Gelatin/chemistry food.ingredient Analytical chemistry 02 engineering and technology Calorimetry 010402 general chemistry Differential Scanning 01 natural sciences Gelatin Phase Transition chemistry.chemical_compound food Differential scanning calorimetry Electrochemistry Animals General Materials Science Spectroscopy Skin Calorimetry Differential Scanning Temperature Surfaces and Interfaces 021001 nanoscience & nanotechnology Condensed Matter Physics Polyelectrolyte 0104 chemical sciences Crystallography chemistry Thermodynamics Cattle Muramidase Electrophoretic light scattering Turbidimetry Absorption (chemistry) Lysozyme 0210 nano-technology |
| Zdroj: | Langmuir, 33(47), 13530-13542. American Chemical Society |
| ISSN: | 1520-5827 0743-7463 |
| Popis: | It is known that the formation of electrostatic polyelectrolyte complexes can induce conformational changes in the interacting macromolecules. However, the opposite effect, namely, that of the helix–coil transition of one of the interacting polyelectrolytes on its associative phase separation with another polyelectrolyte and the possible phase transitions in such systems, has not been determined. Atomic force and confocal laser scanning microscopy, phase analysis, dynamic and electrophoretic light scattering, turbidimetry, absorption, and fluorescence measurements as well as differential scanning calorimetry and rheology were used to study the effect of the helix–coil transition in bovine skin gelatin (Gel) on its associative phase separation with hen egg white lysozyme (Lys) at different temperatures (18–40 °C) and various Lys/Gel weight ratios (0.01–100) at low ionic strength (0.01) and pH 7.0. The effects of the main variables on the phase state, the phase diagram, and the main complexation and binding parameters as well as the temperature and enthalpy of the helix–coil transition of Gel within the complexes were investigated. Associative phase separation is observed only for the system with Gel in the helix state. Effective charge and structure and the solution and rheological behavior of the formed complexes proved to be dependent on the [An–]/[Cat+] charge ratio. The localization of Lys within the complex particles has irregular character without the formation of a single center of binding. The binding of Lys with Gel does not lead to the disruption of its tertiary structure or to an appreciable change in the thermodynamic parameters of the thermal transitions of Lys. Gel in the coil state interacts only weakly with Lys, forming water-soluble complex associates. It is suggested that the Voorn–Overbeek model could potentially describe the stronger binding and phase separation in the case of Gel in the helix state. |
| Databáze: | OpenAIRE |
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