Interaction of bovine α -lactalbumin with fatty acids as determined by partition equilibrium and fluorescence spectroscopy

• Published in: International dairy journal 2006, Vol.16 (1), p.18-25
• Main Authors: Barbana, C., Pérez, M.D., Sánchez, L., Dalgalarrondo, M., Chobert, J.M., Haertlé, T., Calvo, M.
• Format: Article
• Language: English
• Subjects: binding properties; binding sites; Biological and medical sciences; Bovine [formula omitted]-lactalbumin; calcium; chemical interactions; Equilibrium partition; fatty acid-binding proteins; Fatty acids; fluorescence emission spectroscopy; Fluorescence spectroscopy; Food industries; Fundamental and applied biological sciences. Psychology; lactalbumin; milk; Milk and cheese industries. Ice creams; oleic acid; palmitic acid; partition coefficients; protein conformation
• ISSN: 0958-6946; 1879-0143
• DOI: 10.1016/j.idairyj.2005.01.007

The interaction of bovine holo- and apo- α -lactalbumin with fatty acids was studied using a partition equilibrium technique and fluorescence spectroscopy. Using there techniques, bovine holo- α -lactalbumin was found to be unable to bind fatty acids. Gas chromatography analysis also did not reveal and fatty acids bound to bovine α -lactalbumin that had been isolated using non denaturing conditions. The partition equilibrium showed that bovine apo- α -lactalbumin has one binding site for fatty acids, having association constants of 4.6×10 6 and 5.4×10 5 m −1 for oleic and palmitic acids, respectively. The binding of bovine apo- α -lactalbumin studied by fluorescence spectroscopy also showed the existence of a binding site for oleic acid with a binding constant of 3.3×10 6 m −1, but the binding parameters could not be estimated for palmitic acid due to low fluorescence enhancement. These results demonstrate that the conformational change induced in α-lactalbumin by the removal of calcium enables the protein to interact with fatty acids.