ANTIBODY-BINDING PROTEIN HAVING REDUCED ANTIBODY-BINDING CAPACITY IN ACIDIC pH REGIONS

摘要

Provided is a protein A ligand having a reduced antibody-binding capacity in acidic pH regions when the protein A ligand is immobilized on a carrier and an affinity separation matrix is produced. This protein contains an amino acid sequence obtained by replacing, in an amino acid sequence derived from the E, D, A, B, or C domain of a protein A described by SEQ ID NO: 1-5, a hydrophobic amino acid residue of an Fc binding site with another hydrophobic amino acid residue or a polar uncharged amino acid residue. The protein is characterized by having a reduced antibody-binding capacity in acidic pH regions in comparison with the pre-replacement protein.