Abstract: The present invention provides a method for measuring a substrate concentration by accumulating an energy resulting from a reaction between a biocatalyst and a substrate recognized by the biocatalyst to a certain level; and using a dependency of an accumulation rate on the substrate concentration as an index; and a apparatus therefor. In particular, the present invention provides a method in which the measurement of the accumulation rate is carried out by measuring a frequency of an energy release in a certain amount of time when the energy accumulated in the capacitor reaches the certain level and is then released.

Abstract: The present invention provides a method for measuring a substrate concentration by accumulating an energy resulting from a reaction between a biocatalyst and a substrate recognized by the biocatalyst to a certain level; and using a dependency of an accumulation rate on the substrate concentration as an index; and a apparatus therefor. In particular, the present invention provides a method in which the measurement of the accumulation rate is carried out by measuring a frequency of an energy release in a certain amount of time when the energy accumulated in the capacitor reaches the certain level and is then released.

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 are a method for assaying a target substance in a sample and an apparatus for the method. The method can specifically assay the target substance in the sample without using any antibody against the target substance. The assaying method includes simultaneously or successively bringing a labeled aptamer, the target substance in the sample and a solid phase into contact together, and then measuring the label of the aptamer which has not been bound on the solid phase. The labeled aptamer has a property of binding to the target substance. The solid phase carries an oligonucleotide immobilized on it in an excess amount relative to the target substance. The oligonucleotide is hybridizable with the labeled aptamer when the labeled aptamer is in a state that it is not bound to the target substance, but is not hybridizable with the labeled aptamer when the labeled aptamer is in a state that it is bound to the target substance.

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: A DNA encoding a glucose dehydrogenase enzyme having high substrate specificity, can be produced at a low cost, is not affected by oxygen dissolved in a measurement sample and, in particular, has superior thermal stability is described. Cells transformed with the DNA encoding the glucose dehydrogenase enzyme may be used to produce the glucose dehydrogenase by culturing the transformants to produce glucose dehydrogenase as an expression product of the DNA, and collecting the product.

Abstract: The present invention provides a method for measuring a substrate concentration by accumulating an energy resulting from a reaction between a biocatalyst and a substrate recognized by the biocatalyst to a certain level; and using a dependency of an accumulation rate on the substrate concentration as an index; and a apparatus therefor. In particular, the present invention provides a method in which the measurement of the accumulation rate is carried out by measuring a frequency of an energy release in a certain amount of time when the energy accumulated in the capacitor reaches the certain level and is then released.

Abstract: The present invention provides a method for measuring a substrate concentration by accumulating an energy resulting from a reaction between a biocatalyst and a substrate recognized by the biocatalyst to a certain level; and using a dependency of an accumulation rate on the substrate concentration as an index; and a apparatus therefor. In particular, the present invention provides a method in which the measurement of the accumulation rate is carried out by measuring a frequency of an energy release in a certain amount of time when the energy accumulated in the capacitor reaches the certain level and is then released.

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: 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: The present invention relates to a glucose sensor (2) including an electrode (32) which includes a conductive component and glucose dehydrogenase immobilized to the conductive component. As the glucose dehydrogenase, use is made of a protein complex including a catalytic activity subunit which has glucose dehydrogenase activity, and an electron mediator subunit for supplying an electron donated from the catalytic activity subunit to the conductive component. Preferably, the glucose sensor (2) is designed to continuously measure the glucose level or successively measure the glucose level a plurality of times.

Abstract: The present invention provides a method for measuring a substrate concentration by accumulating an energy resulting from a reaction between a biocatalyst and a substrate recognized by the biocatalyst to a certain level; and using a dependency of an accumulation rate on the substrate concentration as an index; and a apparatus therefor. In particular, the present invention provides a method in which the measurement of the accumulation rate is carried out by measuring a frequency of an energy release in a certain amount of time when the energy accumulated in the capacitor reaches the certain level and is then released.

Abstract: An aptamer-probe complex for detecting the presence of a target molecule is disclosed. The complex of the present invention contains an aptamer moiety which is able to bind to an indicator protein and change the properties of the indicator protein, and a probe moiety which is able to bind to a target molecule, wherein the aptamer moiety and the probe moiety are combined in such a manner that the binding mode between the aptamer moiety and the indicator protein changes when the probe moiety binds to the target molecule. A target molecule can be detected with combination of an aptamer which binds to a certain protein, and a probe which binds to the target molecule, utilizing the properties of that protein as an indicator.

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 mutant glucose dehydrogenase having an amino acid sequence at least 80% identical to SEQ ID NO:3 and having glucose dehydrogenase activity, wherein amino acid residues corresponding to positions 326, 365 and 472 of said amino acid sequence are replaced with glutamine, tyrosine and tyrosine, respectively, and wherein said mutant glucose dehydrogenase shows an improved substrate specificity to glucose and a reduced reactivity to disaccharides.

Abstract: A method for measuring a test substance whereby the test substance in a sample can be specifically measured without using an antibody against the test substance; an aptamer molecule used therefor; and a method for creating the aptamer are disclosed. An aptamer capable of hybridizing with an oligonucleotide when it is bound to a test substance, but is incapable of hybridizing with the oligonucleotide when it is not bound to the test substance, is utilized. The aptamer is brought into contact with a sample, and the aptamer bound to the test substance is brought into contact with an immobilized oligonucleotide which hybridizes with the aptamer, to bind the aptamer to a solid phase, followed by measurement of the aptamer immobilized on the solid phase.

Abstract: A DNA encoding a glucose dehydrogenase enzyme having high substrate specificity, can be produced at a low cost, is not affected by oxygen dissolved in a measurement sample and, in particular, has superior thermal stability is described. Cells transformed with the DNA encoding the glucose dehydrogenase enzyme may be used to produce the glucose dehydrogenase by culturing the transformants to produce glucose dehydrogenase as an expression product of the DNA, and collecting the product.

Abstract: A DNA encoding a glucose dehydrogenase enzyme with high substrate specificity and recombinant vectors and transformants for expression of the DNA are disclosed. By culturing the transformant, the glucose dehydrogenase enzyme can be produced at a low cost. The glucose dehydrogenase enzyme produced is not affected by oxygen dissolved in a measurement sample and, in particular, has superior thermal stability.

Abstract: An aptamer-probe complex for detecting the presence of a target molecule is disclosed. The complex of the present invention contains an aptamer moiety which is able to bind to an indicator protein and change the properties of the indicator protein, and a probe moiety which is able to bind to a target molecule, wherein the aptamer moiety and the probe moiety are combined in such a manner that the binding mode between the aptamer moiety and the indicator protein changes when the probe moiety binds to the target molecule. A target molecule can be detected with combination of an aptamer which binds to a certain protein, and a probe which binds to the target molecule, utilizing the properties of that protein as an indicator.

Abstract: A glucose dehydrogenase having high substrate specificity can be produced at a low cost by culturing a microorganism belonging to the genus Burkholderia. The glucose dehydrogenase is isolated from the medium and/or cells of the microorganism. The glucose dehydrogenase isolated from the genus Burkholderia is not affected by oxygen dissolved in a measurement sample and, in particular, has superior thermal stability.