Fc-binding protein, method for producing said protein, and antibody adsorbent using said protein, and methods for purifying and identifying antibody using said adsorbent

Abstract

The present invention addresses the first problem of providing an Fc-binding protein having improved stability, especially stability to heat and acid, of the Fc-binding protein, a method for producing this protein, and an antibody adsorbent using this protein. The present invention also addresses the second problem of providing a method that makes it possible to identify the presence or absence of glycosylation of an antibody, and a material to be used in this method. The first problem is solved by an Fc-binding protein having improved stability to heat and acid obtained by substituting amino acid residues at specific positions in the extracellular domain within human FcγRIIIa with other specific amino acids, a method for producing this protein, and an antibody adsorbent using this protein. The second problem is solved by using an adsorbent capable of specifically adsorbing an antibody having a sugar chain, the adsorbent being obtained by immobilizing human FcγRIIIa on an insoluble carrier.