Revised equilibrium thermodynamic parameters for thermal denaturation of β-lactoglobulin at pH 2.6
| Autor: | Richard K. Owusu Apenten, Despina Galani |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Thermal denaturation
Whey protein medicine.diagnostic_test Chemistry Enthalpy Thermodynamics Condensed Matter Physics Gibbs free energy symbols.namesake Equilibrium thermodynamic Protein stability Spectrophotometry medicine symbols Chemical stability Physical and Theoretical Chemistry Instrumentation |
| Zdroj: | Thermochimica Acta. 363:137-142 |
| ISSN: | 0040-6031 |
| DOI: | 10.1016/s0040-6031(00)00606-7 |
| Popis: | Thermodynamic parameters for thermal denaturation of β-lactoglobulin (β-lg) should account for the dissociation coupled unfolding (DCU) transitions, Dimer⇌Monomer⇌Unfolded state. Purified β-lg (0.4–4 mg ml −1 in 50 mM glycine–glycine–HCl buffer, pH 2.6) was heated and monitored by UV-difference spectrophotometry. The Monomer⇌Unfolded state transition occurred at 65–95°C with T m equal to 82°C and a Gibbs free energy change (Δ G U 0 ) of 51 kJ mol −1 . Such results were combined with parameters for β-lg dissociation leading to the Gibbs free energy change for DCU (Δ G DCU 0 ) of 128 (±8.3) kJ mol −1 . The enthalpy and entropy change for DCU was (Δ H DCU 0 ) equal to 373 kJ mol −1 and (Δ H DCU 0 ) 824 J mol −1 K −1 . Thus, the room temperature stability of β-lg is 76 kJ mol −1 higher than reported previously. The possible significance of such results for protein stability function relations (PSFR) is discussed. |
| Databáze: | OpenAIRE |
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