Arkray, Inc.

Hideaki Yamaoka

Kenji Nagakawa

Mitsuhiro Hoshijima

Koji Katsuki

Shido Kawase

Keisuke Kurosaka

Tomomichi Tsujimoto

Koji Sode

Masashi Tsukada

Sadaaki Kimura

The present invention relates to a protein-immobilized membrane () including a cell membrane homologous layer (A) and a protein (B) immobilized to the cell membrane homologous layer (A), where the protein contains cytochrome or a cytochrome complex. The present invention also relates to a method for forming a protein-immobilized membrane (), and an enzyme-immobilized electrode and a biosensor (X) provided with a protein-immobilized membrane (). Preferably, the cell membrane homologous layer (A) may contain a phospholipid polymer, and the protein (B) may be CyGDH including an &#x3b1; subunit having a glucose dehydrogenase activity and cytochrome C having a function of electron transfer.

Biosensor incorporating protein-immobilized membrane and method of immobilizing protein in biosensor

The present invention relates to a method for purifying target protein which contains electron transfer protein, from a protein solution containing the target protein, by means of liquid chromatography. The liquid chromatography is performed as follows: First, the protein solution is introduced into a column which is filled with a packing agent, thereby causing the packing agent to bond to the target protein. Then, impurities are removed, and then the target protein is eluted from the packing agent in an eluent which contains a hydroxy-cholate. An example of the target protein is glucose dehydrogenase which contains a protein having glucose dehydrogenation activity. The liquid chromatography is performed as a combination of hydrophobic chromatography and anion exchange chromatography.

Method for purifying protein and glucose dehydrogenase

The present invention relates to technology for constructing a reaction system including a test target, an oxidation-reduction enzyme, and an electron mediator, and measuring the concentration of the test target by an electrochemical process. A Ru compound is used as the electron mediator. The present invention provides a concentration test instrument including a substrate, first and second electrodes formed on the substrate, and a reagent layer formed as a solid. The reagent layer contains an oxidation-reduction enzyme and a Ru compound, and is constituted so as to dissolve and construct a liquid phase reaction system when a sample liquid is supplied.

Concentration measuring method, concentration test instrument, and concentration measuring apparatus

A sensor storage container is provided that allows sensors to be checked visually from the outside. A container is used for storing sensors including an oxidation-reduction enzyme that oxidizes or reduces an object to be analyzed, a mediator that mediates the transfer of electrons caused by oxidation or reduction, and a detection means that detects the oxidation or reduction reaction. The container is transparent or semi-transparent in whole or in part and thereby the sensors can be checked visually from the outside of the container. This container may be composed of a container body and a lid. The container body may be provided with a scale. Preferably, the sensors are those produced using a ruthenium metal complex as the mediator.

Sensor storage container

Substrate specificity for glucose of a glucose dehydrogenase having the amino acid sequence of SEQ ID NO: 13 is improved by substituting another amino acid residue for the amino acid residue at position 472 and/or 475.

Mutant glucose dehydrogenase

The present invention relates to a technique for measuring a glucose level by utilizing a reaction system containing an enzyme and an electron carrier. In accordance with the glucose level measuring method of the present invention, glucose dehydrogenase with cytochrome C attached thereto or glucose dehydrogenase derived from a microorganism belonging to agenus is used as the enzyme, and a Ru compound is used as the electron carrier. The present invention further provides a glucose sensor in which glucose dehydrogenase with cytochrome C attached thereto or glucose dehydrogenase derived from derived from a microorganism belonging to agenus is used as the enzyme, and a Ru compound is used as the electron carrier.

Glucose level measuring method and glucose sensor utilizing glucose dehydrogenase

The present invention relates to an analytical instrument () which includes a flow path () for moving a sample containing blood cells, an introduction port () for introducing the sample into the flow path (), a reagent portion () arranged in the flow path (), and an electron detection medium () for obtaining information necessary for analyzing an analysis target component contained in the sample in relation with an amount of electrons transferred. The reagent portion () contains an electron mediator for supplying an electron taken from the analysis target component in the sample to the electron detection medium (), and at least part of the reagent portion is positioned adjacent to the introduction port ().

Analytical instrument having improved arrangement of reagent section and analytical method

A process for producing glucose dehydrogenases. This process comprises transferring a DNA containing a sequence represented by SEQ ID NO:1 which encodes an &#x3b1; subunit having a glucose dehydrogenase activity and a &#x3b2; subunit being an electron transfer protein into a microorganism belonging to the genusto thereby construct a transformant, and culturing this transformant so as to allow the production of a first glucose dehydrogenase containing the above-described &#x3b2; subunit and a second glucose dehydrogenase free from the &#x3b2; subunit. The &#x3b1; subunit as described above has a molecular weight of about 60 kDa measured by, for example, SDS-polyacrylamide gel electrophoresis under reducing conditions, while the &#x3b2; subunit as described above has a molecular weight of about 43 kDa measured by, for example, SDS-polyacrylamide gel electrophoresis under reducing conditions.

Process for producing glucose dehydrogenases

A mutant glucose dehydrogenase having an improved substrate specificity to glucose, which is a protein comprising the amino acid sequence depicted in SEQ ID NO:3 or an amino acid sequence having the substitution, deletion, insertion or addition of one or more amino acid residues excluding amino acid 365 in the amino acid sequence depicted in SEQ ID NO:3 and having a glucose dehydrogenase activity, the amino acid residue corresponding to amino acid 365 being substituted by other amino acid residue.

Method of measuring glucose concentration and glucose sensor with the use of glucose dehydrogenase

The present invention relates to a measuring instrument () comprising a channel () for moving a sample liquid (BL) containing a solid component (B) and providing a liquid reaction field and first and second electrodes () which are used to apply voltage to the liquid reaction field. The first electrode () has an electron transfer interface () for transferring electrons between it and the liquid reaction field when voltage is applied to the liquid reaction field via the first and second electrodes (). The measuring instrument () comprises concentrating means () for increasing the concentration of solid components at portions thereof which contact the electron transfer interface () in the liquid reaction field. The concentrating means () preferably comprises a water-absorbing layer containing an absorbent polymer material.

Measuring instrument provided with solid component concentrating means

A biosensor (I) which comprises a capillary () having a passage () fined with an inlet () for taking a sample solution therein, a membrane () for accelerating the transference of a sample solution in the passage (), and a reaction portion () containing a reagent which reacts with a component to be detected in a sample solution.

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Kyoto, Japan

Hideaki Yamaoka