b'Protein purification and immunoprecipitationIon exchange (IEX) and affinity chromatography are two strategies commonly used for partial or one-step protein purification. IEX chromatography enables the separation of proteins based on the protein charge at a particular pH. Since multiple proteins may have similar charges, IEX chromatography generally enables only partial purification of a protein of interest. Affinity chromatography is enabled by specific binding of a protein to an immobilized ligand. Because the protein of interest is tightly bound, contaminants can be removed through wash steps, and the bound protein can be stripped (eluted) from the support in a highly purified form. Affinity purification produces higher protein yields and requires fewer steps than other purification methods.Immunoprecipitation (IP) is small-scale affinity purification of antigens using a specific antibody that is immobilized to a solid support, and is one of the most widely used methods for isolation of proteins and other biomolecules from cell or tissue lysates for the purpose of subsequent detection by western blotting or other techniques. Other similar techniques include co-immunoprecipitation (co-IP) and pull-down, which are similar to IP except that the target antigen is used to co-precipitate its binding partner(s) or associated protein complex from the lysate.Protein purification productsHigh-performance resins and magnetic beads for maximum protein yieldOur protein purification portfolio offers a broad range of products for ion exchange and affinity-based isolation of proteins and antibodies in microgram to kilogram quantities. Strong anion or cation exchange resins provide an intermediate level of purification during multi-step isolation or act as a polishing step during the final stages of purification. Biotinylated or recombinant proteins can be conveniently captured using avidin-based or affinity tagbased binding supports. Customized protein purification can be achieved by immobilizing ligands to the appropriate support. Accessory products are available for increased convenience, including disposable columns and binding and elution buffers. Rapid protein screening or IP, co-IP, and pull-down applications can be completed utilizing magnetic beadbased resins and kits, as described on pages 3537.Highlights:Broad product selectionstrong ion exchange and affinity supports for purification and enrichment of proteins and antibodies; affinity ligands enable one-step purification of recombinant and biotinylated proteins, while activated supports provide a platform for custom protein immobilization (Table 1)High performanceresins are designed to maximize protein yield and reduce background More formatsmagnetic beads, loose resins, FPLC cartridges, and 96-well filter plates enable protein purification from screening and small-scale phases to process-scale purification (Table 2)Economicalpricing that is similar to or better than products from other leading suppliers30 Protein purification thermofisher.com/proteinbiology'