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The interaction between Beta-lactoglobulin and sodium N-dodecyl sulphate
The Biochemical Journal
|March 1, 1976
Summary
Sodium n-dodecyl sulphate binding to beta-lactoglobulin causes protein aggregation at low concentrations. At higher concentrations, aggregation depends on ionic strength, with enthalpy changes indicating complex formation and conformational changes.
Area of Science:
- Biochemistry
- Protein-surfactant interactions
- Thermodynamics
Background:
- Beta-lactoglobulin is a major whey protein.
- Understanding protein-surfactant interactions is crucial for food and pharmaceutical industries.
Purpose of the Study:
- To investigate the binding of sodium n-dodecyl sulphate (SDS) to beta-lactoglobulin.
- To characterize the thermodynamic and structural changes associated with this binding.
Main Methods:
- Equilibrium dialysis
- Ultracentrifugation
- Microcalorimetry
Main Results:
- Complexes aggregate at low SDS binding concentrations (<30 anions/protein).
- Aggregation is salt-dependent at higher binding concentrations.
- Enthalpy of interaction suggests stepwise complex formation and conformational changes.
Conclusions:
- The interaction between SDS and beta-lactoglobulin is ionic at low binding concentrations.
- Protein conformational changes accompany SDS binding.
- Ionic strength significantly influences aggregation behavior at higher binding levels.