Human serum gamma-globulin binds copper cations.

Binding of copper cations to human serum gamma-globulin was studied using molecular ultrafiltration. The content of free metal in the filtrate was evaluated by the reaction with sodium diethyldithiocarbamate. Conformation characteristics of the protein were evaluated by UV spectrophotometry. gamma-Globulin molecule has several copper-binding sites differing by binding constants and filled one-by-one as the content of bound metal increased.