rProtein G Beads is an affinity chromatography medium designed for the one-step purification of immunoglobulins from biological fluids and cell culture media. The coupling of recombinant protein G ligand to 4% agarose beads in rProtein G Beads optimizes the binding capacity to immunoglobulins. With the chemical stability and high batch-to-batch reproducibility of the medium, rProtein G Beads is excellent for isolating immune complexes.
Protein G is a bacterial cell wall component isolated from group G Steptococci. Likewise to Protein A, Protein G binds to the Fc regions of mammalian IgG. The non-specific albumin and cell surface binding sites in recombinant protein G have been eliminated, while maintaining the IgG binding sites. The binding characteristics of protein G and protein A are attributed to their significantly different amino acid compositions. In comparison with Protein A, Protein G can be used for the purification of a wider spectrum of mammalian (i.e. human, mouse and rat) monoclonal and polyclonal IgG-class antibodies at high binding affinity, but not with other classes of immunoglobulins (i.e. IgM, IgD and IgA).