Protein A isolated from Staphylococcus aureus, Cowan strain, is a 41,000D protein capable of binding to the Fc portion of immunoglobulin. This interaction is not species specific, as Protein A has been shown to bind IgG from a variety of species. The binding was thought to be restricted to IgG but subsequent studies have demonstrated that Protein A can interact with IgA, IgM, and subclasses of IgG from different species. Protein A is attached through a stable linkage to heat stable, cross-linked 4% agarose beads. The method of attachment allows for maximum immunoglobulin binding capacity and ease of elution. Agarose Protein A can be used for immunoglobulin purification, immunoprecipitation of antigens or other applications involving specific immunoglobulin binding. Protein A has been coupled at 2mg/ml of gel. Applications: Suitable for use in ELISA.