Recombinant Protein G

Protein G is a bacterial cell wall protein expressed at the cell surface of certain group C and group G Streptococcal strains. It has affinity for both Fab- and Fc-fragments of human IgG by independent and separate binding sites. Protein G binds preferentially to the Fc portion of IgG, but can also bind to the Fab region, making it useful for purification of F (ab') fragments of IgG. Binding to the Fc region of immunoglobulins from several species by a non-immune mechanism exhibits great affinity for almost all mammalian immunoglobulin G (IgG) classes, including all human IgG subclasses (IgG1, IgG2, IgG3 and IgG4) and also rabbit, mouse, and goat IgG. Protein G has also been shown to bind human serum albumin but at a site that is structurally separated from the IgG-binding region. Protein G shows a broader range of binding to IgG subclasses than staphylococcal protein A. Protein G was found to be a powerful reagent for the detection of IgG, and consequently the antigen against which these antibodies are directed. It was used in Western blot analyses to detect various antigen-antibody complexes on nitrocellulose membranes. Due to it's affinity for the Fc region of many mammalian immunoglobulins, protein G is considered a universal reagent in biochemistry and immunology. Moreover, protein G is widely used as a ligand coupled to resins in affinity chromatography for antibody purification.

Store at ≤-70°C, stable for 6 months after receipt. Store at ≤-70°C, stable for 3 months under sterile conditions after opening. Please minimize freeze-thaw cycles and use a manual defrost freezer.