The Thermo Scientific™ Pierce™ Chromatography Cartridges Protein L are convenient, ready-to-use prepacked devices for isolation and purification of immunoglobulin classes IgG, IgM, IgA, IgE and IgD via their kappa light chains.

Pierce Protein L Agarose consists of recombinant Protein L that has been covalently immobilized onto high-quality crosslinked 6% beaded agarose (CL-6B). This particular variety of the resin provides the most versatile combination of chromatographic features for high yield and high purity purification of target immunoglobulins. The agarose beads have physical and chemical properties suitable for many affinity purification systems.

Features of Pierce Protein L Agarose:

• Protein L – immobilized Protein L is ideal for selective purification of human and mouse antibodies that have kappa light chains
• Agarose resin – support is crosslinked 6% beaded agarose (CL-6B), the most popular resin for protein affinity purification methods
• Inert and stable – superior manufacturing method immobilizes Protein L by charge-free, leach-resistant covalent bonds, resulting in low nonspecific binding and enabling multiple uses without decline in yield
• Standard capacity – Pierce Protein L Agarose has a normal load of immobilized Protein L, providing a binding capacity of 5 to 10 mg human IgG/mL resin

Pierce Chromatography Cartridges are compatible with the major automated liquid-chromatography systems or for manual syringe processing, and attach directly to ÄKTA™ or FPLC Systems without additional connectors. An accessory pack, included with each product, readily adapts columns for use with Luer-Lok Syringe Fittings or 1/16” tubing. Protein L cartridges provide fast, easy and reproducible chromatographic separations and can be regenerated for multiple uses.

Applications:
• Purify monoclonal and polyclonal antibodies that bind poorly to Protein A or Protein G agarose
• Purify monoclonal antibodies from culture supernatants supplemented with bovine serum
• Protein L immunoprecipitation and co-immunoprecipitation assays
• Purify ScFv and Fab fragments containing kappa light chains

Protein L is an immunoglobulin-binding protein (36kDa) that originates from the bacteria Peptostreptococcus magnus, but is now produced recombinantly in E. coli. Unlike Protein A and Protein G, which bind primarily through Fc regions (i.e., heavy chain) of immunoglobilins, Protein L binds Igs through interactions with the light chains. Because no part of the heavy chain is involved in the binding interaction, Protein L binds a wider range of Ig classes than Protein A or G. Protein L binds to representatives of all classes of Ig, including IgG, IgM, IgA, IgE and IgD. Single chain variable fragments (ScFv) and Fab fragments also bind to Protein L.

Despite this wide-ranging binding capability with respect to Ig classes, Protein L is not a universal immunoglobilin-binding protein. Binding of Protein L to immunoglobulins is restricted to those containing kappa light chains (i.e., kappa chain of the VL domain). In humans and mice, kappa light chains predominate. The remaining immunoglobulins have lambda light chains. Furthermore, Protein L is effective in binding only certain subtypes of kappa light chains. For example, it binds human VkI, VkIII and VkIV subtypes but does not bind the VkII subtype. Binding of mouse immunoglobulins is restricted to those having VkI light chains.

Given these specific requirements for effective binding, the main application for immobilized Protein L is purification of monoclonal antibodies from ascites or culture supernatant that are known to have the kappa light chain. Protein L is extremely useful for purification of VLk-containing monoclonal antibodies from culture supernatant because it does not bind bovine immunoglobi