Interaction of Bovine β-Lactoglobulin and Other Bovine and Human Whey Proteins with Retinol and Fatty Acids

Abstract

The interaction of bovine and human whey proteins with retinol and palmitic acid has been studied. Using gel filtration it was found that bovine β-lactoglobulin and α-lactalbumin and serum albumin from both species bind retinol in vitro while the ability to bind palmitic acid is restricted to bovine β-lactoglobulin and bovine and human serum albumin. Using equilibrium dialysis, β-lactoglobulin was found to display two binding sites for retinol per dimeric molecule with an association constant of 1.5×10⁴M^-1. Competition experiments showed that when the concentration ratio between total fatty acids and retinol is similar to that found in milk, palmitic acid competes with the binding of retinol to β-lactoglobulin.