Abstract: Provided are a protein L-derived immunoglobulin binding protein having an increased antibody dissociation rate under acidic conditions, and an affinity support using the same. Disclosed are an immunoglobulin binding protein comprising at least one mutant of an immunoglobulin binding domain, and an affinity support comprising a solid-phase support having the immunoglobulin binding protein bound thereto. A mutant of the immunoglobulin binding domain consists of an amino acid sequence having an identity of at least 85% with the sequence set forth in any one of SEQ ID NO:1 to SEQ ID NO:9 and a predetermined mutation, and the mutant has immunoglobulin ? chain binding activity.

Abstract: Provided are a protein L-derived immunoglobulin binding protein having an increased alkali tolerance, and an affinity support using the same. Disclosed are an immunoglobulin binding protein comprising at least one mutant of an immunoglobulin binding domain, and an affinity support comprising a solid-phase support having the immunoglobulin binding protein bound thereto. A mutant of the immunoglobulin binding domain consists of an amino acid sequence having an identity of at least 85% with the sequence set forth in any one of SEQ ID NO:1 to SEQ ID NO:9 and a predetermined mutation, and the mutant has immunoglobulin ? chain binding activity.

Abstract: To provide a porous particle with which non-specific adsorption is hardly generated although the porous particle is a synthetic polymer-based particle, the mechanical strength is high, and the dynamic binding capacity is high in a case where a ligand is bound to the porous particle; and a method for producing the same. A method for producing a porous particle, including the following steps 1 and 2; (step 1) dissolving at least one or more of polymers selected from the group consisting of a vinyl alcohol polymer and an ethylene-vinyl alcohol copolymer in an aqueous solvent to prepare a polymer solution; and (step 2) dispersing the polymer solution in a non-aqueous solvent to form a W/O emulsion.

Abstract: An affinity support having improved binding capacity for target proteins. An immunoglobulin-binding protein including a mutant immunoglobulin-binding domain, an affinity support including a solid-phase support and the immunoglobulin-binding protein immobilized thereto. The mutant immunoglobulin-binding domain consists of an amino acid sequence having at least 85% identity with an amino acid sequence of any of SEQ ID NOs: 1 to 12.

Abstract: This invention relates to a method of producing a probe-bound carrier, a probe-bound carrier and a method of detecting or separating a target substance. The method of producing a probe-bound carrier includes: step 1 of mixing a carrier having tosyl groups and a probe; and step 2 of reducing the amount of tosyl groups on a surface of a carrier, in which a proportion of area S2 that is occupied by one tosyl group on a surface of the carrier obtained in the step 2 with respect to area S1A that is occupied by one tosyl group on a surface of the carrier used in the step 1 (S2/S1A×100%) is not less than 140%.

Abstract: The present invention relates to a magnetic particle dispersion, and the magnetic particle dispersion includes a magnetic particle, an isothiazoline compound, and an aqueous medium.

Abstract: The present invention relates to composite particles, coated particles, a method of producing composite particles, a ligand-containing solid phase carrier, and a method of detecting or separating a target substance in a sample. The above described composite particles each contains an organic polymer and inorganic nanoparticles, wherein the content of the inorganic nanoparticles in the composite particles is more than 80% by mass, and wherein the composite particles have a volume average particle size of from 10 to 1,000 nm.