RESUMO
Samples of human serum gamma-globulin modified by equimolar binding of copper and zinc cations were obtained using the method of molecular ultrafiltration. Conformation characteristics of the protein were studied by UV spectrophotometry. Immunochemical study included radial immunodiffusion test, direct and sandwich enzyme immunoassays. Conformation changes in gamma-globulin caused by incorporation of solitary metal cations into the protein molecule modified presentation of antigenic determinants on the globule surface and their availability for recognition by specific antibodies. New antigenic determinants and new antigenic specificity of gamma-globulin are not formed under these conditions.
Assuntos
Cobre/metabolismo , Zinco/metabolismo , gama-Globulinas/metabolismo , Ensaio de Imunoadsorção Enzimática , Epitopos/química , Epitopos/imunologia , Epitopos/metabolismo , Humanos , Ligação Proteica , Conformação Proteica , Espectrofotometria Ultravioleta , gama-Globulinas/química , gama-Globulinas/imunologiaRESUMO
Binding of zinc cations to human serum gamma-globulin was studied by molecular ultrafiltration. The content of free metal in the filtrate was evaluated by reaction with o-phenanthroline. Conformation characteristics of the protein were determined by UV spectrophotometry. Our findings suggest that gamma-globulin molecule contains several zinc binding sites differing by corresponding constants and successively occupied with increase in the content of bound metal. The parameters of zinc binding correspond to those obtained in experiments with copper. Conformation status of protein with bound zinc differs significantly from that of protein with bound copper cations.
Assuntos
Cátions/metabolismo , Globinas/metabolismo , Zinco/metabolismo , Globinas/química , Humanos , Fenantrolinas , Ligação Proteica , Conformação Proteica , Espectrofotometria Ultravioleta , Ultrafiltração , Zinco/análiseRESUMO
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.
