Capture step

The first chromatography step in purification, which binds the product from the clarified harvest, concentrates it and removes most impurities. For antibodies and Fc-fusion proteins it is usually Protein A affinity chromatography; other products use other affinity, ion exchange or mixed-mode resins. Dynamic binding capacity, resin lifetime and leaching of the ligand into the product are the parameters that matter most for cost and quality. Japanese documents also use the loanword for capture.