Abstract: A method for measuring an analyte in a sample by using a redox reaction is provided, which gives values with excellent reliability. Prior to the redox reaction, at least one of a sulfonic acid compound and a nitro compound is added to the sample to eliminate the influence of hemoglobin and any hemoglobin degradation products as reducing substances contained in the sample. Subsequently, a reducing or oxidizing substance derived from the analyte is caused to generate, and the amount thereof is measured by the redox reaction. The amount of the analyte is determined from the measurement value. The sulfonic acid compound may be sodium lauryl sulfate, and the nitro compound may be 4-nitrophenol, etc.

Abstract: A method of determining glycated hemoglobin is provided, by which a ratio of the glycated hemoglobin in a sample can be determined accurately and easily. The ratio of glycated hemoglobin can be determined by degrading a glycated hemoglobin in a whole blood sample selectively with a protease to give a glycated hemoglobin degradation product; causing a redox reaction between a glycation site of the glycated hemoglobin degradation product and a fructosyl amino acid oxidoreductase; and determining this redox reaction. Further, as shown in FIG. 1, in a whole blood sample, there is a correlation between the ratio of the glycated hemoglobin determined by this method and an HbA1c concentration. Thus, without determining the glycated ?-amino group as a characteristic structure of HbA1c, an amount of HbA1c can be determined accurately and easily from the determined ratio of the glycated hemoglobin.

Abstract: A test strip having the capability of separating blood cells from whole blood, wherein it has a porous reagent layer comprising beads, an inorganic gel and a reagent that causes a detectable reaction with a substance to be detected, and a substrate that supports the reagent layer, wherein the beads are adhered to each other with the inorganic gel, and interstices are formed between the beads to trap a solid. The test strip can thus be used for separating blood cells from a whole blood including blood cells and plasma and detecting a substance to be detected, such as glucose, contained in plasma. The use of the test strip allows the measurement of a substance to be detected even by measurement of a transmitted light, the exhibition of good oxygen permeability, and thus can be used for measuring a substance to be detected with improved accuracy.

Abstract: A method of measuring an analyte, comprising a step of measuring a detectable substance by using a reaction system including a formation reaction of the detectable substance based on a chemical reaction of the analyte contained in a sample, wherein a layered inorganic compound is caused to exist in the reaction system including the formation reaction of the detectable substance, whereby high-sensitivity measurement is made possible, the detectable substance can be stabilized to improve accuracy of the measurement, a rate of a chemical reaction is increased to enable quick measurement, and high-sensitivity measurement is made possible even in a reaction system which forms an insoluble substance.

Abstract: A method for stabilizing a hemolyzed sample that does not affect an accuracy of determination in a measurement even after the sample is left standing at room temperature, and a hemolysis reagent solution used therefor are provided. Using a hemolysis reagent solution in which a surfactant is contained and carbon dioxide is dissolved, blood cells are hemolyzed so as to prepare a hemolyzed sample. Even after the thus prepared hemolyzed sample is stored at room temperature, for example, glycated proteins or the like can be measured with an accuracy of determination similar to that for the hemolyzed sample immediately after preparation. The concentration of the carbon dioxide dissolved in the hemolyzed sample at 2° C. to 35° C. is at least 8 mmol/L.

Abstract: A method of measuring an analyte, comprising a step of measuring a detectable substance by using a reaction system including a formation reaction of the detectable substance based on a chemical reaction of the analyte contained in a sample, wherein a layered inorganic compound is caused to exist in the reaction system including the formation reaction of the detectable substance, whereby high-sensitivity measurement is made possible, the detectable substance can be stabilized to improve accuracy of the measurement, a rate of a chemical reaction is increased to enable quick measurement, and high-sensitivity measurement is made possible even in a reaction system which forms an insoluble substance.

Abstract: The present invention provides a fructosylamine oxidase which is obtainable by culturing Fusarium proliferatum, and purifying two types of fructosylamine oxidase (FAO) with different substrate specificities from the culture, and which is useful in the measurement of amadori compounds.

Abstract: A method of assaying a glycated protein in a sample with the use of redox reaction, in which highly reliable measurement can be obtained. A sample containing a glycated protein is treated with protease in the presence of a sulfonic acid compound, so that the glycated protein is degraded. The glycated portion of the resultant glycated protein degradation product is reacted with fructosyl amino acid oxidase, and this redox reaction is measured, thereby determining the amount of glycated protein. Sodium lauryl sulfate can be used as the sulfonic acid compound.

Abstract: A method for measuring an analyte in a sample by using a redox reaction is provided, which gives values with excellent reliability. Prior to the redox reaction, at least one of a sulfonic acid compound and a nitro compound is added to the sample to eliminate the influence of hemoglobin and any hemoglobin degradation products as reducing substances contained in the sample. Subsequently, a reducing or oxidizing substance derived from the analyte is caused to generate, and the amount thereof is measured by the redox reaction. The amount of the analyte is determined from the measurement value. The sulfonic acid compound may be sodium lauryl sulfate, and the nitro compound may be 4-nitrophenol, etc.

Abstract: The present invention provides a highly reliable method of measuring an analyte in a sample using a redox reaction. In this method, a formazan compound is added to a sample prior to a redox reaction so as to eliminate the influence of any reducing substance in the sample. Thereafter, a reducing substance or an oxidizing substance derived from the analyte is formed, and the amount of the formed substance is measured by the redox reaction. The amount of the analyte is determined from the amount of the formed substance thus measured. As the formazan compound, for example, 1-(4-iodophenyl)-3-(2,4-disulfophenyl)-5-(2,4-dinitrophenyl) formazan can be used.

Abstract: The present invention provides a method of preventing erroneous color development of N-(carboxymethylaminocarbonyl)-4,4?-bis(dimethylamino)diphenylamine sodium salt as a color-developing substrate, thereby improving the accuracy of measurement utilizing a redox reaction performed using the color-developing substrate. A tetrazolium compound, sodium azide, and the color-developing substrate are added to a sample in the presence of a surfactant. A reaction between an oxidizing substance derived from an analyte in the sample and the color-developing substrate, which develops color by oxidation, is caused by an oxidoreductase. By measuring the color developed, the amount of the oxidizing substance is determined. The concentrations of the respective components in the reaction solution are set so that 0.01 to 1 mmol of the tetrazolium compound, 0.003 to 0.5 mmol of the sodium azide, and 0.006 to 0.

Abstract: The present invention provides a method of measuring a glycated protein in a sample using a redox reaction, by which the glycated protein can be measured accurately with high sensitivity. In order to remove a glycated amino acid present in the sample other than the glycated protein, the glycated amino acid is degraded in advance by causing a fructosyl amino acid oxidase to act thereon, and thereafter, a fructosyl amino acid oxidase is caused to act on the glycated protein in the presence of a tetrazolium compound and sodium azide to cause a redox reaction. The amount of the glycated protein is determined by measuring the redox reaction. As the glycated protein, glycated hemoglobin is preferable.

Abstract: The present invention provides a method of pretreating a sample containing a glycated amine as an analyte, thereby enabling highly reliable measurement of a glycated amine. A glycated amino acid in the sample is degraded by causing a fructosyl amino acid oxidase (FAOD) to act thereon, and thereafter, a FAOD further is caused to act on the glycated amine as the analyte in the sample to cause a redox reaction. The amount of the glycated amine is determined by measuring the redox reaction. The substrate specificity of the FAOD caused to act on the glycated amino acid may be either the same as or different from that of the FAOD caused to act on the glycated amine. When using the same FAOD, a FAOD is caused to act on the glycated amino acid to degrade it, and thereafter, the sample is treated with a protease to inactivate the FAOD and also to degrade the glycated amine.

Abstract: The present invention relates to a novel enzyme (&agr;-GARE) which releases an amino acid residue having a glycated &agr;-amino group (&agr;-GA) from a glycated protein etc. and to bacterial strains producing the same. Examples of the bacterial strains include Sphingomonas parapaucimobilis KDK1004 (FERM BP-7041). The &agr;-GARE is contained in the culture supernatant of this strain and &agr;-GA can be released from a glycated peptide by using the same, as shown in FIG. 1.

Abstract: The present invention relates to a novel enzyme (&agr;-GARE) which releases an amino acid residue having a glycated &agr;-amino group (&agr;-GA) from a glycated protein etc. and to bacterial strains producing the same. Examples of the bacterial strains include Sphingomonas parapaucimobilis KDK1004 (FERM BP-7041). The &agr;-GARE is contained in the culture supernatant of this strain and &agr;-GA can be released from a glycated peptide by using the same, as shown in FIG. 1.

Abstract: The present invention relates to a novel enzyme (&agr;-GARE) which releases an amino acid residue having a glycated &agr;-amino group (&agr;-GA) from a glycated protein etc. and to bacterial strains producing the same. Examples of the bacterial strains include Corynebacterium ureolyticum KDK1002 (FERM P-17135) and Pseudomonas alcaligenes KDK1001 (FERM P-17133). The &agr;-GARE is contained in the culture supernatant of these strains and &agr;-GA can be released from a glycated peptide by using the same, as shown in FIG. 1.

Abstract: A method of determining Hb is provided, by which an amount of Hb can be determined easily and accurately without fear of damage to the environment. Hemoglobin in a sample is denatured with a tetrazolium compound to give denatured hemoglobin, and an amount of an optical change in the sample is measured at an absorption wavelength specific to the denatured hemoglobin. Using the amount of the optical change thus measured, an amount of the hemoglobin in the sample can be determined. The amount of the optical change preferably is measured at a wavelength in a range from 520 to 670 nm. According to this method, an amount of Hb can be determined with high accuracy as shown in FIG. 1.

Abstract: A method for storing a tetrazolium compound stably is provided. The tetrazolium compound is stored in the presence of sodium azide. The tetrazolium compound (A) and the sodium azide (B) are present at a ratio (A:B) in the range from 1:0.02 to 1:6.2. Furthermore, when the tetrazolium compound is stored as a solution, the concentration of the sodium azide is in the range from 0.08 to 3.2 mmol/L and the concentration of the tetrazolium compound is in the range from 0.5 to 8 mmol/L. As the tetrazolium compound, it is preferable to use 2-(4-iodophenyl)-3-(2,4-dinitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium salt.

Abstract: A method of determining Hb is provided, by which an amount of Hb can be determined easily and accurately without fear of damage to the environment. Hemoglobin in a sample is denatured with a tetrazolium compound to give denatured hemoglobin, and an amount of an optical change in the sample is measured at an absorption wavelength specific to the denatured hemoglobin. Using the amount of the optical change thus measured, an amount of the hemoglobin in the sample can be determined. The amount of the optical change preferably is measured at a wavelength in a range from 520 to 670 nm. According to this method, an amount of Hb can be determined with high accuracy as shown in FIG. 1.

Abstract: A method of measuring an analyte, comprising a step of measuring a detectable substance by using a reaction system including a formation reaction of the detectable substance based on a chemical reaction of the analyte contained in a sample, wherein a layered inorganic compound is caused to exist in the reaction system including the formation reaction of the detectable substance, whereby high-sensitivity measurement is made possible, the detectable substance can be stabilized to improve accuracy of the measurement, a rate of a chemical reaction is increased to enable quick measurement, and high-sensitivity measurement is made possible even in a reaction system which forms an insoluble substance.