αs-casein inhibits the pressure-induced aggregation of β-lactoglobulin through its molecular chaperone-like properties

In this work, the effects of αs-casein (αs-CN) on the pressure-induced aggregation of β-lactoglobulin (β-Lg) were studied. αs-CN depressed the pressure-induced aggregation of β-Lg, and this function was dependent on the concentration of αs-CN and the pressure holding time. Furthermore, αs-CN altered the aggregation process of β-Lg by suppressing the transition of the aggregate from the soluble phase to the insoluble phase and, as a result, the fraction of insoluble aggregates was decreased. During this process, αs-CN formed stable complexes with the denatured β-Lg and the formation of complexes prevented further aggregation of β-Lg and solubilized aggregated β-Lg to a small degree of polymerization. These results indicate that αs-CN exhibits a chaperone-like activity under high pressure, and provide an insight into the possible mechanism by which αs-CN accomplishes the task of stabilizing proteins to resist the pressure-induced aggregation of β-Lg.