A study of multi-ligand beta-lactoglobulin complex formation

Beta-lactoglobulin (beta-LG), the principal whey protein, possesses multiple sites for binding ligands. Most studies of beta-LG-ligand interactions have focused on the formation and dissociation of protein complexes with single ligands, such as alpha-tocopherol, resveratrol or folic acid. In this study, the possibility of a plurality of bioactive compounds binding simultaneously to beta-LG was analysed using protein intrinsic fluorescence quenching. It was found that beta-LG could bind two or three ligands simultaneously, although the sequence in which the ligands were added affected binding affinity. The impact of binding to BAG on physicochemical properties of these three ligands is discussed in view of fluorescence spectroscopy and high performance liquid chromatography results. The data obtained in this study suggest the feasibility of developing beta-LG-based carriers of a plurality of active compounds. (C) 2014 Elsevier Ltd. All rights reserved.