Tosoh Corporation

Sagami Chemical Research Institute

Kouta Hatayama

Teruhiko Ide

Toru Tanaka

Hiroyuki Ito

Satoshi Endo

Yosuke Terao

Naoki Yamanaka

Yoshiharu Asaoka

The problem to be addressed by the present invention is to provide improved recombinant Fc&#x3b3;RIIb and Fc&#x3b3;RIIa that do not require refolding and exhibit high productivity and thermal stability, and to provide a method for producing the same. Said problem is solved by improved recombinant Fc&#x3b3;RIIb comprising at least the amino acid residues of the extracellular domain of human Fc&#x3b3;RIIb (No. 43 to No. 215 in UniProt No. P31994), wherein, in said amino acid residues, at least one amino acid substitution has occurred at a position corresponding to No. 82, 94, 98, 104, 105, or 139 in UniProt No. P31994. Said problem is also solved by improved recombinant Fc&#x3b3;RIIa comprising at least the amino acid residues of the extracellular domain of human Fc&#x3b3;RIIa (No. 34 to No. 206 in UniProt No. P12318-1), wherein, in said amino acid residues, at least one amino acid substitution has occurred at a position corresponding to No. 73, 85, 89, 95, 96, or 130 in UniProt No. P12318-1.

Recombinant Fc&#x3b3;RII

Disclosed are: an Fc binding protein having increased stability with respect to heat, acid, and/or alkalinity compared with the wild type; a method for producing same; and a method for specifically isolating protein containing an Fc binding protein binding site using said Fc binding protein as a ligand for affinity chromatography. An Fc binding protein was obtained having increased stability with respect to heat, acid, and/or alkalinity compared with the wild-type human Fc receptor by means of substituting at least one specific amino acid residue in the extracellular domain of the wild-type human Fc receptor with another amino acid residue. The Fc binding protein is useful as a ligand for affinity chromatography for example by immobilizing in a solid phase. Also, when the Fc binding protein is expressed using a host that has been transformed with an expression vector containing a polynucleotide coding for said protein, the amount of produced protein is increased compared with using a wild-type human Fc receptor.

FC binding protein and method for manufacturing same

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Kanagawa, Japan

Kouta Hatayama