Protein G Sepharose 4FF is an affinity chromatography medium prepared by coupling recombinant protein G to a highly cross-linked agarose matrix. It offers a broader binding spectrum compared to protein A, demonstrating enhanced binding capacity for IgG. Protein G not only binds to the Fc fragment of antibodies but also exhibits a weak interaction with the Fab fragment. Consequently, Protein G Sepharose 4FF is commonly used for the separation and purification of antibodies or antibody fragments from cell culture supernatants or cell extracts, as well as for purifying polyclonal antibodies from sera of various animal species.