Abstract: A biosensor according to an embodiment includes: a working electrode; a counter electrode; a reference electrode; and a detection layer contacting the working electrode and containing a crosslinking agent, an electrically conductive polymer, and an enzyme transferring and receiving electrons to and from the working electrode, the reference electrode being a polarized electrode.

Abstract: A biosensor includes a plurality of electrodes including a working electrode, and a detection layer containing an enzyme for exchanging electrons with the working electrode, a crosslinking agent and an electrically conductive polymer and having a contact area with the working electrode defined by a predetermined area.

Abstract: A biosensor includes a plurality of electrodes including a working electrode, and a detection layer which is immobilized on the working electrode and contains a crosslinking agent, an electrically conductive macromolecule and an enzyme transferring and receiving electrons to and from the working electrode. The working electrode is in an open system.

Abstract: An enzyme electrode includes an electrode, and a detection layer which contacts the electrode and contains a crosslinking agent, an electrically conductive macromolecule and an enzyme transferring and receiving electrons to and from the electrode and does not contain an electron transfer subunit.

Abstract: The present invention provides an enzyme electrode composed of a carbon particle on which glucose dehydrogenase (GDH) with flavine adenine dinucleotide (FAD) as a coenzyme is supported and an electrode layer contacting the carbon particle, wherein the carbon particle and/or the electrode layer are/is composed of the carbon particles with a particle diameter of not more than 100 nm and a specific surface area of at least 200 m2/g.

Abstract: A measuring method of measuring a concentration of a target ingredient in a sample by using a sensor including an interdigitated array electrode that includes a first electrode and a second electrode, and a reagent layer on the interdigitated array electrode, the measuring method includes: applying a voltage to between the first electrode and the second electrode; measuring a first current value of an electric current flowing between the first electrode and the second electrode; measuring a second current value of the current flowing between the first electrode and the second electrode; calculating the concentration of the target ingredient in the sample, based on a third current value; calculating a correction value, based on the first current value and the second current value; and a step of correcting the concentration of the target ingredient in the sample, based on the correction value.

Abstract: Amino acid mutation(s) can be introduced to Sclerotinia sclerotiorum- or Aspergillus niger-derived glucose dehydrogenase to obtain a glucose dehydrogenase variant with significantly enhanced productivity in E. coli. The glucose dehydrogenase of the present invention is low reactive with xylose.

Abstract: A modified pyrroloquinoline quinone glucose dehydrogenase that exhibits a high selectivity for glucose is provided. A modified pyrroloquinoline quinone glucose dehydrogenase is disclosed in which the amino acid residue G at Position 99 of a pyrroloquinoline quinone glucose dehydrogenase (PQQGDH) represented by SEQ ID NO: 1, or the amino acid residue G at Position 100 of the pyrroloquinoline quinone glucose dehydrogenase (PQQGDH) represented by SEQ ID NO: 3, is substituted by the amino acid sequence TGZN (where Z is SX, S, or N and X is any amino acid residue). The modified PQQGDH of the present invention may additionally comprise one or more mutations selected from the group consisting of Q192G, Q192A, or Q192S; L193X; E277X; A318X; Y367A, Y367F, or Y367W; G451C; and N452X (where X is any amino acid residue).

Abstract: A fusion protein of pyrroloquinoline quinone glucose dehydrogenase (PQQGDH) and a cytochrome is disclosed. PQQGDH is, for example, a water-soluble PQQGDH derived from Acinetobacter calcoaceticus. The cytochrome is, for example, an electron transfer domain of quinohemoprotein ethanol dehydrogenase from Comamonas testosteroni. The fusion protein of the present invention shows intramolecular electron transfer from PQQ, a redox center, to the cytochrome, which allow construction of a direct electron transfer-type glucose sensor which requires no electron mediators.

Abstract: Disclosed is a modified glucose dehydrogenases that has dramatically increased productivity in Escherichia coli and dramatically increased thermal stability, which is obtained by introducing specific amino acid mutations to glucose dehydrogenase derived from Botryotinia fuckeliana. Also disclosed is a modified glucose dehydrogenases that has dramatically increased productivity in E. coli and dramatically increased thermal stability, which is obtained by replacing two amino acid residues in glucose dehydrogenase of fungal origin with cysteine residues. The novel glucose dehydrogenase has a low reactivity to xylose.

Abstract: Compositions, devices, kits and methods are disclosed for assaying glucose with a glucose oxidase mutant that has been modified at an amino acid residue involved in the active site. The glucose oxidase mutant has reduced oxidase activity while substantially maintaining its dehydrogenase activity.

Abstract: In one form, a fructosyl peptidyl oxidase derived from a budding yeast Phaeosphaeria nodorum for assaying a glycated protein in a sample is provided. The fructosyl peptidyl oxidase has higher activity toward fructosyl valine as well as fructosyl valyl histidine, and may be useful in assaying HbA1c with higher sensitivity and specificity. Still, other forms include unique methods, techniques, systems and devices involving a fructosyl peptidyl oxidase.

Abstract: A modified pyrroloquinoline quinone glucose dehydrogenase that exhibits a high selectivity for glucose is provided. A modified pyrroloquinoline quinone glucose dehydrogenase is disclosed in which the amino acid residue G at Position 99 of a pyrroloquinoline quinone glucose dehydrogenase (PQQGDH) represented by SEQ ID NO: 1, or the amino acid residue G at Position 100 of the pyrroloquinoline quinone glucose dehydrogenase (PQQGDH) represented by SEQ ID NO: 3, is substituted by the amino acid sequence TGZN (where Z is SX, S, or N and X is any amino acid residue). The modified PQQGDH of the present invention may additionally comprise one or more mutations selected from the group consisting of Q192G, Q192A, or Q192S; L193X; E277X; A318X; Y367A, Y367F, or Y367W; G451C; and N452X (where X is any amino acid residue).

Abstract: Amino acid mutation(s) can be introduced to Sclerotinia sclerotiorum- or Aspergillus niger-derived glucose dehydrogenase to obtain a glucose dehydrogenase variant with significantly enhanced productivity in E. coli. The glucose dehydrogenase of the present invention is low reactive with xylose.

Abstract: A modified pyrroloquinoline quinone glucose dehydrogenase that exhibits a high selectivity for glucose is provided. A modified pyrroloquinoline quinone glucose dehydrogenase is disclosed in which the amino acid residue G at Position 99 of a pyrroloquinoline quinone glucose dehydrogenase (PQQGDH) represented by SEQ ID NO: 1, or the amino acid residue G at Position 100 of the pyrroloquinoline quinone glucose dehydrogenase (PQQGDH) represented by SEQ ID NO: 3, is substituted by the amino acid sequence TGZN (where Z is SX, S, or N and X is any amino acid residue). The modified PQQGDH of the present invention may additionally comprise one or more mutations selected from the group consisting of Q192G, Q192A, or Q192S; L193X; E277X; A318X; Y367A, Y367F, or Y367W; G451C; and N452X (where X is any amino acid residue).

Abstract: A biosensor, comprising an insulating base plate, an electrode system containing at least a working electrode and a counter electrode and formed on the insulating base plate, and a sample-supplying section formed on the electrode system, wherein the sample-supplying section has a reaction layer comprising: a first reaction layer formed on the electrode system and containing at least a redox enzyme into which pyrroloquinoline quinone (PQQ), flavin adenine dinucleotide (FAD), or flavin mononucleotide (FMN) is incorporated as a prosthetic group; and a second reaction layer formed by applying, onto the first reaction layer, a solution including a lipid decomposing enzyme.

Abstract: Compositions, devices, kits and methods are disclosed for assaying cholesterol with a cholesterol oxidase mutant that has been modified at an amino acid residue involved in the active site. The cholesterol oxidase mutant has reduced oxidase activity while substantially maintaining its dehydrogenase activity.

Abstract: Compositions, devices, kits and methods are disclosed for assaying glucose with a glucose oxidase mutant that has been modified at an amino acid residue involved in the active site. The glucose oxidase mutant has reduced oxidase activity while substantially maintaining its dehydrogenase activity.

Abstract: In one form, a fructosyl peptidyl oxidase derived from a budding yeast Phaeosphaeria nodorum for assaying a glycated protein in a sample is provided. The fructosyl peptidyl oxidase has higher activity toward fructosyl valine as well as fructosyl valyl histidine, and may be useful in assaying HbA1c with higher sensitivity and specificity. Still, other forms include unique methods, techniques, systems and devices involving a fructosyl peptidyl oxidase.

Abstract: In one form, a fructosyl peptidyl oxidase derived from a budding yeast Phaeosphaeria nodorum for assaying a glycated protein in a sample is provided. The fructosyl peptidyl oxidase has higher activity toward fructosyl valine as well as fructosyl valyl histidine, and may be useful in assaying HbA1c with higher sensitivity and specificity. Still, other forms include unique methods, techniques, systems and devices involving a fructosyl peptidyl oxidase.