Abstract: The objective of the present invention is to provide a method for effectively and easily reducing an amount of a specific impurity in a liquid. The method for reducing an amount of a nucleic acid in a liquid according to the present invention is characterized in comprising the steps of contacting the liquid with a water-insoluble magnesium compound to adsorb at least a part of the nucleic acid on the water-insoluble magnesium compound. Also, the objective of the present invention is to provide an adsorbing filter useful for purifying a useful substance, such as an antibody and an antibody-like molecule, used as a purification material for effectively removing an impurity with easily maintaining the yield of the target substance due to excellent adsorption ability to a nucleic acid and low adsorption ability to an antibody, an antibody-like molecule or the like. The adsorbing filter is characterized in comprising the layer comprising a water-insoluble magnesium compound.

Abstract: The objective of the present invention is to provide a method for efficiently supporting a thiol group-including compound on an insoluble base material. The method for supporting a thiol group-including compound on an insoluble base material according to the present invention is characterized in comprising Step A: treating the thiol group-including compound with a thiol group-including organic reducing agent and an inorganic reducing agent, and Step B: contacting a reaction liquid of said Step A with the insoluble base material.

Abstract: An affinity separation matrix includes a water-insoluble base material; and a ligand that is immobilized on the water-insoluble base material, wherein the ligand is an antibody ? chain variable region-binding peptide comprising B5 domain of Protein L derived from Peptostreptococcus magnus 312 strain or a part thereof.

Abstract: A method for purifying an antibody or an antibody fragment containing ?-chain variable region includes adsorbing at least one of the antibody or the antibody fragment onto an affinity separation matrix by contacting a liquid sample with the affinity separation matrix, washing the affinity separation matrix to remove impurities, and separating the at least one of the antibody or the antibody fragment from the affinity separation matrix by using an acetate buffer. The liquid sample includes the at least one of the antibody or the antibody fragment. The affinity separation matrix includes a water-insoluble carrier and a ligand selected from the group consisting of Protein L, a variant of Protein L, a domain of Protein L, and a variant of the domain. The ligand is immobilized on the water-insoluble carrier.

Abstract: An object of the present invention is to provide a Fab region-binding peptide having an excellent ability for binding to a Fab region of IgG, an affinity separation matrix having the peptide as a ligand, and a method for producing a Fab region-containing protein, the method using the affinity separation matrix. Further, another object of the present invention is to provide a DNA encoding for the peptide, a vector containing the DNA, and a transformant which has been transformed by the vector. The Fab region-binding peptide according to the present invention is characterized in having a mutation at a specific site in comparison with wild-type SpG-?1.

Abstract: The objective of the present invention is to provide a peptide of which both of binding forces to a Fc region and a Fab region are superior. In addition, the objective of the present invention is to provide a DNA which encodes the peptide, a vector which contains the DNA, and a transformant which is transformed by the vector. The problem can be solved by providing the peptide having the specific sequence.

Abstract: 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.

Abstract: A method for purifying an antibody or an antibody fragment containing ?-chain variable region includes adsorbing at least one of the antibody or the antibody fragment onto an affinity separation matrix by contacting a liquid sample with the affinity separation matrix, washing the affinity separation matrix to remove impurities, and separating the at least one of the antibody or the antibody fragment from the affinity separation matrix by using an acetate buffer. The liquid sample includes the at least one of the antibody or the antibody fragment. The affinity separation matrix includes a water-insoluble carrier and a ligand selected from the group consisting of Protein L, a variant of Protein L, a domain of Protein L, and a variant of the domain. The ligand is immobilized on the water-insoluble carrier.

Abstract: A method for producing an antibody fragment includes preparing a liquid sample that includes the antibody fragment and does not include an Fc fragment, adsorbing the antibody fragment on an affinity separation matrix by contacting the liquid sample with the affinity separation matrix, removing impurities from the affinity separation matrix by washing the affinity separation matrix, and separating the antibody fragment from the affinity separation matrix. The antibody fragment includes a CH1 region and does not include an Fc region. The affinity separation matrix includes a water-insoluble carrier and a ligand immobilized on the water-insoluble carrier. The ligand is Protein G, a Protein G domain, a Protein G variant or a Protein G domain variant.

Abstract: A method for producing an affinity separation matrix includes immobilizing a ? chain variable region-binding peptide on a water-insoluble carrier through a terminal cysteine residue of the ? chain variable region-binding peptide. The cysteine residue is located at an N-terminal or a C-terminal of the ? chain variable region-binding peptide. The ? chain variable region-binding peptide is a ligand having an affinity for a ? chain variable region. The affinity separation matrix includes the ligand and the water-insoluble carrier.

Abstract: 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.

Abstract: A method for producing a protein includes adsorbing a protein including a ? chain variable region on an insoluble carrier of an affinity separation matrix by contacting a liquid sample including the protein with the affinity separation matrix; washing the affinity separation matrix to remove impurities; separating the protein from the affinity separation matrix by using an acidic buffer; and regenerating the affinity separation matrix by using an alkaline aqueous solution after the protein is separated from the affinity separation matrix. The insoluble carrier includes a ligand immobilized on the insoluble carrier, and the ligand is a ? chain variable region-binding peptide including B5 domain of Protein L derived from Peptostreptococcus magnus 312 strain or a variant of the B5 domain. The adsorbing, the washing, and the separating are repeated 3 or more times.

Abstract: An object of the present invention is to provide a technique to create novel engineered protein ligands that, when immobilized through a lysine residue (its side chain ?-amino group) which allows for efficient immobilization to a carrier, show the optimum binding capacity and binding efficiency to a target molecule. The present invention provides an engineered protein having a sequence obtained by replacing all the lysine residues in Protein A, which is the most typical protein ligand, with other amino acids, and adding lysine at a terminal; and an affinity separation matrix in which such an engineered protein is immobilized on a water-insoluble carrier by reductive amination or the like. This affinity separation matrix is characterized by its high binding capacity to a target molecule even when the immobilized amount of the ligand is small.

Abstract: An object of the present invention is to develop techniques to create novel engineered protein ligands that maximize the binding capacity and binding efficiency to a target molecule of affinity separation matrices on which the protein ligands are immobilized. The present invention provides protein ligands (variants) that can be immobilized on carriers in a manner shown in schematic FIG. 1(4)-(15), as well as antibody affinity separation matrices obtained by immobilizing such a protein ligand on a water-insoluble carrier. The affinity separation matrices are characterized by their excellent binding capacity and binding efficiency to a target molecule.

Abstract: The objective of the present invention is to provide a peptide of which both of binding forces to a Fc region and a Fab region are superior. In addition, the objective of the present invention is to provide a DNA which encodes the peptide, a vector which contains the DNA, and a transformant which is transformed by the vector. The problem can be solved by providing the peptide having the specific sequence.

Abstract: The objective of the present invention is to provide an affinity separation matrix having excellent adsorption performance and binding capacity to a peptide containing a Fab region of IgG, and a method for producing a Fab region-containing peptide using the affinity separation matrix. The affinity separation matrix according to the present invention is characterized in that a Fab region-binding peptide is immobilized as a ligand on a water-insoluble carrier in a density of 1.0 mg/mL-gel or more.

Abstract: An affinity separation matrix includes a water-insoluble base material; and a ligand that is immobilized on the water-insoluble base material, wherein the ligand is an antibody ? chain variable region-binding peptide comprising B5 domain of Protein L derived from Peptostreptococcus magnus 312 strain or a part thereof.

Abstract: An object of the present invention is to provide a Fab region-binding peptide having an excellent ability for binding to a Fab region of IgG, an affinity separation matrix having the peptide as a ligand, and a method for producing a Fab region-containing protein, the method using the affinity separation matrix. Further, another object of the present invention is to provide a DNA encoding for the peptide, a vector containing the DNA, and a transformant which has been transformed by the vector. The Fab region-binding peptide according to the present invention is characterized in having a mutation at a specific site in comparison with wild-type SpG-?1.

Abstract: 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.

Abstract: An object of the present invention is to develop techniques to create novel engineered protein ligands that maximize the binding capacity and binding efficiency to a target molecule of affinity separation matrices on which the protein ligands are immobilized. The present invention provides protein ligands (variants) that can be immobilized on carriers in a manner shown in schematic FIG. 1(4)-(15), as well as antibody affinity separation matrices obtained by immobilizing such a protein ligand on a water-insoluble carrier. The affinity separation matrices are characterized by their excellent binding capacity and binding efficiency to a target molecule.