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: 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 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 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: 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 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: 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: 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 disclosure discloses an enzyme electrode comprising; an electrode comprising a current collector; a monolayer-forming molecule bound to the surface of the current collector; and a glucose dehydrogenase comprising a cytochrome C subunit bound to the monolayer-forming molecule; wherein electrons are transferred between the glucose dehydrogenase and the current collector by oxidation-reduction reaction of the glucose dehydrogenase.

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: A method for quantifying a substance, which method includes the steps of: introducing a sample containing a measurement target substance to a biosensor comprising an enzyme electrode comprising an electrode and an oxidoreductase placed on the electrode in a state where direct electron transfer with the electrode occurs, and a counter electrode; applying an AC voltage to the enzyme electrode to carry out impedance measurement; and calculating the substance concentration based on an index obtained by the impedance measurement; is provided.

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 disclosure discloses an enzyme electrode comprising; an electrode comprising a current collector; a monolayer-forming molecule bound to the surface of the current collector; and a glucose dehydrogenase comprising a cytochrome C subunit bound to the monolayer-forming molecule; wherein electrons are transferred between the glucose dehydrogenase and the current collector by oxidation-reduction reaction of the glucose dehydrogenase.

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: 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: 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: 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.