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 nonspecific 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.
Contains two Fc-binding domains per protein
Better than Protein A for mouse (incl. IgG1), human (incl. IgG3) and rat, goat and cow antibodies
Poorer than Protein A for guinea pig, pig, dog and cat