Richardson diagram – an image of a red ribbon protein.

Protein A chromatography relies on the specific binding of antibodies to an immobilized Protein A ligand. Native Protein A or surface Protein A (SPA), is a 55-kDa bacterial cell wall-derived component that naturally binds to IgG molecules.
Modifications to the first generation of Protein A ligands has given way to highly robust and caustic stable purification resins that allow you to design antibody purification processes with greater flexibility. Thermo Fisher Scientific offers Protein A chromatography resins which are designed to help you improve the efficiency and productivity of your antibody purification process.

Native Protein A Structure and Binding Sites

Native Protein A has 5-homologous binding domains (A-E) that fold into a 3-helix bundle; each of which bind to proteins across a range of mammalian species, most notably human IgG. Long regarded as the platform of choice for antibody purification, Protein A binds to IgG1, IgG2 and IgG4 class molecules and has affinity towards:

  1. The CH2-CH3 interface of the antibody tail (Fc region).
  2. Multiple subsets of the Vh region referred to as the variable heavy chain region (Vh3).
Key defining the binding sites within a staphylococcus aureus molecule.

Protein A Purification Solutions

Thermo Fisher Scientific offers various Protein A affinity resins constructed of different ligands and bead matrices. These resins are built to:

  • Obtain high dynamic binding capacity
  • Design processes with greater flexibility
  • Improve impurity clearance and yield
  • Reduce unit operations


Thermo Scientific MabCaptureC Affinity Matrix


Designed for high productivity, featuring a highly cross-linked agarose-based backbone. The engineered Protein A affinity ligand on this resin is equipped with:

  • High dynamic binding capacity
  • Increased alkaline stability
  • Superior performance characteristics

Learn more

Thermo Scientific™ MabCaptureC™ Affinity Matrix, 1 L

Bioprocessing resources

Access a targeted collection of scientific application notes, case studies, posters, white papers and more for bioprocessing:

Pharmaceutical Grade Reagent. For Manufacturing and Laboratory Use Only.