Purified (unconjugated) Pierce™ Recombinant Protein G is useful as the basis for preparing various kinds of probes or affinity media for detection or purification of rabbit and human antibodies, especially IgG isotypes, in immunoassays and antibody purification protocols.

• Contains two Fc-binding domains per protein
• Does not bind human IgM, IgD or IgA
• More efficient than Protein A for mouse (IgG₁), human (IgG₃) and rat, goat and cow antibodies
• Less efficient than Protein A for guinea pig, pig, dog and cat

Protein G is a bacterial cell wall protein isolated from group G Streptococci. DNA sequencing of native Protein G identifies two IgG-binding domains and sites for albumin and cell surface binding. The albumin and cell surface binding domains have been eliminated from Recombinant Protein G to reduce non specific binding and, therefore, can be used to separate IgG from crude samples. Optimal binding occurs at pH 5, although binding is also effective at pH 7,0 to 7,2.