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Beta-lactoglobulin denaturation by dissociation-coupled unfolding

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Galani, D and Apenten, Richard KO (1999) Beta-lactoglobulin denaturation by dissociation-coupled unfolding. Food Research International , 32 (2). pp. 93-100. [Journal article]

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Abstract

Many food proteins have multiple subunits. Beta-lactoglobulin (beta-1g) dimer was assessed for its resistance to subunit dissociation and unfolding in 0-8 M urea. Equilibrium denaturation profiles were monitored by ultraviolet difference spectrophotometry. The results were analysed by a new dissociation coupled unfolding (DCU) model. The Gibbs free energy change for denaturing beta-1g (Delta G(DCU)(0)) was 60 (+/- 2.3) kJ mol(-1) at pH 7 and 72 (+/- 1.6) kJ mol(-1) at pH 2.6. By comparison, the dissociation free energy for beta-1g dimer (Delta G(D)) is 26.0 kJ mol(-1) at pH 7 and 22.6 kJ mol(-1) at pH 2.6. Hence, dimerization accounts for 43% (pH 7) and 32% (pH 2.6) of the stability of native beta-1g dimer. Such results indicate a 3-state denaturation process in urea with native beta-1g monomer acting as a stable intermediate during DCU. The issues raised by a study of beta-1g may be relevant to other multisubunit proteins in food systems.

Item Type:Journal article
Keywords:BOVINE ALPHA-LACTALBUMIN; NERVE GROWTH-FACTOR; THERMAL-DENATURATION; CONFORMATIONAL STABILITY; EQUILIBRIUM DENATURATION; ESCHERICHIA-COLI; GLOBULAR-PROTEINS; SELF-ASSOCIATION; SPECTROSCOPY; RESOLUTION
Faculties and Schools:Faculty of Life and Health Sciences
Faculty of Life and Health Sciences > School of Biomedical Sciences
Research Institutes and Groups:Biomedical Sciences Research Institute
Biomedical Sciences Research Institute > Northern Ireland Centre for Food and Health (NICHE)
ID Code:14699
Deposited By:Dr Richard Owusu-Apenten
Deposited On:03 Aug 2010 08:49
Last Modified:28 Jan 2014 14:46

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