Adsorption of human beta 2-microglobulin at a water/mercury interface.

Adsorption of human beta 2-microglobulin from a neutral solution of 0.15 M NaCl on a mercury surface was studied at 25 degrees C by measurement of the differential capacity of the electrical double layer. From the diffusion-controlled adsorption kinetics, the surface concentration and hence the area occupied by the adsorbed beta 2-microglobulin molecule were determined at various potentials of the mercury surface. The results indicate unfolding or flattening of beta 2-microglobulin molecules adsorbed in particular on the electrically uncharged surface. The extent of this interfacial conformational rearrangement was reduced with growing positive or negative surface charge density.