Recombinant Protein G (E. coli)

Protein G is a bacterial cell wall protein expressed at the cell surface of certain group C and group G Streptococcal strains. 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. Moreover, protein G is widely used as a ligand coupled to resins in affinity chromatography for antibody purification.