Fc-fusion proteins are Ig Fc-domains linked to proteins with therapeutic potential. These can favorably increase serum half-life and alter the immunol. properties of the biopharmaceutical. There are currently 13 com. approved Fc-fusion biopharmaceuticals on the market and many more in clin. trials. Protein A affinity chromatog. is a favorable capture step for its specificity. Fc-fusion protein purification can be challenging since they tend to have lower dynamic binding capacities (DBCs) than traditional monoclonal antibodies. Contributing factors can be decreased Fc-domain affinity or attachment of large target mols. In this study, DBC and purification properties of four com. available Protein A chromatog. resins are compared using four Fc-fusion proteins. Purification performance in terms of recovery yield, elution volume, HCP reduction, and aggregate removal for two of the mols. was explored and found to be similar. Major factors affecting DBC are particle diameter, pore diameter (dpore), binding capacity (qmax), and pore diffusion. The smallest mol. had less steric hinderance and showed a pos. correlation between DBC and qmax. However, pos. correlations were found between DBC and dpore for the three larger mols., meaning that these (150-200kDa) were able to enter the pores more readily allowing Amsphere A3 to out-perform the other three resins tested.