Preparation of specimens of human serum gamma-globulin modified by copper and zinc and its immunochemical characteristics.

Specimens of human serum gamma-globulin modified by molar excess of copper and zinc cations were obtained by molecular ultrafiltration. Conformation characteristics of the protein were determined by UV spectrophotometry. Immunochemical study included radial immunodiffusion test and direct and sandwich enzyme-linked immunosorbent assay. After binding of copper and zinc, the gamma-globulin molecule underwent conformation changes modifying presentation of antigenic determinants on the globule surface and their availability for recognition by specific antibodies. The effects of copper were much more pronounced than those of zinc cations.