The present invention provides a high performance glucose sensor which can demonstrate high stability against preservation and produces only a low blank value. The glucose sensor comprises an electrically insulating base plate, an electrode system formed on the base plate, and a reaction layer which is formed in contact with or in the vicinity of the electrode system and contains at least a glucose dehydrogenase whose coenzyme is pyrrolo-quinoline quinone, the reaction layer further containing an additive such as phthalic acid.
The present invention relates to a method for lowering activity with respect to maltose in glucose measurement comprising a step of reacting modified pyrroloquinoline quinone dependent glucose dehydrogenase subjected to amino acid sequence modification, wherein pyrroloquinoline quinone dependent glucose dehydrogenase is reacted in the presence of at least one type of substance selected from the group comprising succinic acid, malonic acid, glutaric acid, malic acid, phthalic acid, 2-ketoglutaric acid, 3,3-dimethylglutaric acid, pimeric acid, suberic acid, adipic acid, maleic acid, potassium chloride, ammonium chloride, diammonium hydrogen citrate, L-lysine, taurine, calcium glycerate, amino-n-butyric acid, sodium glycolate, sodium .alpha.-ketoglutarate, fumaric acid, glycine, glutamic acid, serine and citric acid.
The invention relates to a method for improving the heat stability of glucose dehydrogenase (GDH), comprising a step of combining, in a composition comprising soluble coenzyme-bound glucose dehydrogenase (GDH), the enzyme with any one or more selected from the group consisting of sugar alcohols, carboxyl group-containing compounds, alkali metal-containing compounds, alkali earth metal compounds, ammonium salts, sulfate salts and proteins, thereby improving the heat stability of GDH over that achieved without the inclusion of the compounds.
A method and apparatus for non-invasively determining the concentration of a substance in blood, such as glucose, include a sample portion arranged for contacting an eye region of a user to obtain a tear fluid sample, a sensor in communication with the sample portion for generating a signal related to the tear substance concentration, and a processor in communication with the sensor for determining a blood substance concentration corresponding to the tear substance concentration.
Reagents for detecting an analyte are described. A reagent comprises (a) an enzyme selected from the group consisting of a flavoprotein, a quinoprotein, and a combination thereof; and (b) a mediator selected from the group consisting of a phenothiazine, a phenoxazine, and a combination thereof. In addition, reagents having good stability to radiation sterilization are described. Electrochemical sensors and sampling devices comprising such reagents, methods of producing a sterilized device including such reagents, and methods for detecting an analyte which utilize such reagents are described as well.
