Absorption of Bovine Serum Albumin at Air-Water Interface and Penetration into Lipid Monolayers

Abstract

Bovine serum albumin (BSA) is adsorbed slowly to air-water interface from inside the aqueous solution at relatively low concentration. Small amount of adsorbed BSA scarcely increased surface pressure enough to make measurement possible. Lipids were spread after some time for BSA to be adsorbed at the water surface. New method to estimate the adsorbed amount of BSA was devised, and it is concluded that below 1 mg·m^-2 the diffusion process is important in adsorption, that unfolding of BSA occurs rapidly and that above 1 mg·m^-2, the protein molecules adsorbed are mostly native.