Protein A is a cell wall component of Staphylococcus aureus. It consists of a single polypeptide chain shaped as a cylinder, which contains five antibody binding domains. These high affinity regions are specifically bound to the Fc region of immunoglobulins (IgGs).
Protein A is temperature stable and it retains its native conformation even in the presence of denaturing agents. Protein A resins have been widely used to purify a broad range of immunoglobulins from different mammalian species.
Protein A Agarose characteristics
|Matrix||4% cross-linked agarose|
|Bead size||50-150 µm|
|Binding capacity||~ 25 mg human IgG / ml resin|
|Ligand density||~ 3 mg rProtein A / ml resin|
|Linear flow rate||500 cm/h|
|Maximum pressure||1.5 bar (21.8 psi)|