Protein L based affinity chromatography is used for the capture of antibodies and antibody fragments that do not bind to protein A. Unlike protein A and G, which bind to the Fc region of immunoglobulins (IgGs), protein L binds through interactions with the variable region of an antibody’s kappa light chain.

TOYOPEARL AF-rProtein L-650F is an affinity chromatography resin that combines a rigid polymer matrix with a recombinant protein L ligand, which is derived from the B4 domain of native protein L from Peptostreptococcus magnus and is expressed in E.coli. Code optimization of the domain results in high binding capacity and an improved alkaline stability of the ligand compared to the native molecule.

The selected recombinant protein L ligand also has an affinity for a broad range antibody subclasses.

This application note demonstrates the ability of TOYOPEARL AF-rProtein L-650F resin to capture and purify Fabs and scFv fragments with a high dynamic binding capacity (DBC) of >50 mg Fab/mL resin at 4 min residential time. This recombinant protein L ligand is stable at 0.1 mol/L NaOH.