Kaneka Corporation

Yoshiyuki Nakano

Shinichi Yoshida

Masayuki Takano

Dai Murata

Keita Iguchi

Shunichi Taira

Junya Akagi

An object of the present invention is to create a novel engineered Protein A ligand having better antibody dissociation properties in the acidic condition compared with known engineered Protein A ligands. The present invention provides a protein having an affinity for an immunoglobulin, including an amino acid sequence obtained by introducing, into an amino acid sequence derived from any of E, D, A, B and C domains of Protein A, at least one amino acid substitution at any one or more of amino acid residues corresponding to positions 31 to 37 of the A, B and C domains (positions 29 to 35 of the E domain, positions 34 to 40 of the D domain), which are conserved in all the domains, the protein having a lower affinity for an Fab region of an immunoglobulin than a protein having the amino acid sequence before introduction of the substitution.

Protein capable of binding specifically to immunoglobulin, and immunoglobulin-binding affinity ligand

An object of the present invention is to create a novel engineered Protein A ligand having better antibody dissociation properties in the presence of an acid than conventional engineered Protein A ligands and a further object of the present invention is to create a novel engineered Protein A ligand having higher alkali resistance. The present invention is to provide a protein having an affinity for an immunoglobulin, including an amino acid sequence derived from any of E, D, A, B and C domains of Protein A, wherein at least one Gly residue in the amino acid sequence is replaced with an amino acid other than Ala, and the protein has a lower affinity for an Fab region of an immunoglobulin than a protein including an amino acid sequence in which the Gly residue is replaced with Ala. Also, the present invention is to provide the protein having an affinity for an immunoglobulin, which has improved chemical stability in an alkaline condition compared to the corresponding domain.

Protein having affinity for immunoglobulin, and immunoglobulin-binding affinity ligand

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Takasago, Japan

Yoshiyuki Nakano