Binding of Lipophilic Nutrients to β-Lactoglobulin Prepared by Bioselective Adsorption

摘要

The binding of the lipophilic nutrients, retinal, vitamin D_2, and retinyl palmitate by β-lactoglobulin was measured by analysis of changes in the fluores- cence of the tryptophanyl residue of β-lactoglobulin or the retinyl moiety. The fluorescence intensity of the tryptophanyl residue was quenched by retinoid or vitamin D binding but was enhanced by palmitate binding. The analysis of competitive binding experi- ments with palmitate indicated that retinal and palmitate did not compete for the same site; however, vitamin D_2, which binds with a stoichiometry of 2, appeared to displace palmitate at higher concentra- tions.