Abstract: Devices and methods are disclosed for measuring a target substance concentration in a sample utilizing a biosensor.

Abstract: Engineered D-?-hydroxybutyrate dehydrogenases (BHBDhs) are disclosed. In some embodiments, the BHBDhs are derived from enzymes which are putative homologues of A. faecalis-derived BHBDh, including from thermophilic bacteria and radiation-resistance bacteria. These BHBDhs may also comprise additional mutations to increase their catalytic activity. Further, BHBDhs modified to include an NAD-binding loop, so as to tightly bind an NAD+ co-factor, are also disclosed.

Abstract: Compositions, devices, kits and methods are disclosed for assaying lactate with an engineered lactate oxidoreductase. The engineered lactate oxidoreductase has increased stability.

Abstract: A method for quantifying a target substance, comprising: bringing a sample containing the target substance into contact with a biosensor which comprises an enzyme electrode containing an oxidoreductase and a counter electrode; measuring a change in the potential difference between the enzyme electrode and the counter electrode due to oxidation reaction of the target substance catalyzed by the oxidoreductase; and calculating the concentration of the target substance based on the change in the potential difference; wherein a potential is applied between the enzyme electrode and the counter electrode before the measurement of the change in the potential difference.

Abstract: By using a mutant glucose oxidase comprising an amino acid sequence in which a residue corresponding to isoleucine at position 489 or arginine at position 335 in the amino acid sequence of SEQ ID NO:1 is substituted with an amino acid residue having a reactive functional group in a side chain, and binding an electron acceptor to the mutant glucose oxidase through the amino acid residue having a reactive functional group, an electron acceptor-modified glucose oxidase is obtained.

Abstract: A mutant cytochrome protein originated from a cytochrome protein having three heme-binding domains, which mutant cytochrome protein lacks the first heme-binding domain and the second heme-binding domain as counted from the N-terminus, is provided. The mutant cytochrome protein may lack a region(s) containing the first and second heme-binding domains.

Abstract: The present invention provides a mutant FAD-dependent glucose dehydrogenase comprising: a catalytic subunit; an electron transfer subunit; and a hitchhiker subunit; wherein each of the amino acid sequence of the catalytic subunit and the amino acid sequence of the electron transfer subunit comprises a cysteine residue introduced therein, the catalytic subunit and the electron transfer subunit being bound to each other through a disulfide bond between the cysteine residues to achieve improved thermal stability of the FAD-dependent glucose dehydrogenase.

Abstract: Compositions, devices, kits and methods are disclosed for assaying triglyceride with a glycerol 3-phosphate oxidase mutant. The glycerol 3-phosphate oxidase mutant has reduced oxidase activity while substantially maintaining, or increasing, its dehydrogenase activity, compared to the wild-type glycerol 3-phosphate oxidase.

Abstract: A molecular recognition element comprising a target molecule-recognizing portion, and a direct electron transfer-type oxidoreductase linked to the target molecule-recognizing portion.

Abstract: A method for measuring a glycated protein in a sample, the method comprising (1) a step of allowing a sample in which a degradation product has been generated from a glycated protein by a protease to react with an oxidoreductase in the presence of an electron mediator to generate a reduced electron mediator; and (2) a step of detecting the reaction state in the step (1) by an electrochemical technique using an interdigitated electrode.

Abstract: A mutant cytochrome protein originated from a cytochrome protein having three heme-binding domains, which mutant cytochrome protein lacks the first heme-binding domain and the second heme-binding domain as counted from the N-terminus, is provided. The mutant cytochrome protein may lack a region(s) containing the first and second heme-binding domains.

Abstract: Methods and apparatus for detecting binding of a diabetes-related target molecule analyte in a sample utilizing Electrochemical Impedance Spectroscopy (EIS). Sensor electrodes include a diabetes-related target-capturing molecule immobilized thereto, and an EIS-based imaginary impedance measurement is utilized to arrive at a concentration of the analyte.

Abstract: A mutant cytochrome protein originated from a cytochrome protein having three heme-binding domains, which mutant cytochrome protein lacks the first heme-binding domain and the second heme-binding domain as counted from the N-terminus, is provided. The mutant cytochrome protein may lack a region(s) containing the first and second heme-binding domains.

Abstract: By using a mutant glucose oxidase comprising an amino acid sequence in which a residue corresponding to isoleucine at position 489 or arginine at position 335 in the amino acid sequence of SEQ ID NO:1 is substituted with an amino acid residue having a reactive functional group in a side chain, and binding an electron acceptor to the mutant glucose oxidase through the amino acid residue having a reactive functional group, an electron acceptor-modified glucose oxidase is obtained.

Abstract: The purpose of the present invention is to provide a fungus-derived FADGDH that has a direct electron transfer ability. Provided is a fusion protein comprising a fungus-derived FADGDH or a mutant thereof and a cytochrome molecule connected to the N-terminus of the FADGDH or variant thereof.

Abstract: By using a mutant glucose oxidase comprising an amino acid sequence in which a residue corresponding to isoleucine at position 489 or arginine at position 335 in the amino acid sequence of SEQ ID NO:1 is substituted with an amino acid residue having a reactive functional group in a side chain, and binding an electron acceptor to the mutant glucose oxidase through the amino acid residue having a reactive functional group, an electron acceptor-modified glucose oxidase is obtained.

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: A molecular recognition element comprising a target molecule-recognizing portion, and a direct electron transfer-type oxidoreductase linked to the target molecule-recognizing portion.

Abstract: By using a mutant glucose oxidase comprising an amino acid sequence in which a residue corresponding to isoleucine at position 489 or arginine at position 335 in the amino acid sequence of SEQ ID NO:1 is substituted with an amino acid residue having a reactive functional group in a side chain, and binding an electron acceptor to the mutant glucose oxidase through the amino acid residue having a reactive functional group, an electron acceptor-modified glucose oxidase is obtained.

Abstract: A method for quantifying a target substance, comprising: bringing a sample containing the target substance into contact with a biosensor which comprises an enzyme electrode containing an oxidoreductase and a counter electrode; measuring a change in the potential difference between the enzyme electrode and the counter electrode due to oxidation reaction of the target substance catalyzed by the oxidoreductase; and calculating the concentration of the target substance based on the change in the potential difference; wherein a potential is applied between the enzyme electrode and the counter electrode before the measurement of the change in the potential difference.