What is protein A chromatography?

Protein A chromatography is the most frequently used affinity chromatography method in biomanufacturing. It is the standard technique for capturing recombinant monoclonal antibodies, which relies on the reversible and specific binding between the immobilized protein A ligand and antibodies.

Each protein A molecule has five immunoglobulin-binding domains, and each domain can bind proteins from many mammalian species, most notably Immunoglobulin G (IgG). The primary binding site is the heavy chain within the Fc region of most IgG. Through such a binding between protein A and the Fc region of IgG, antibodies are retained on the column, which later can be eluted in a purified and concentrated form.