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: 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: 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 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: 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: 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 measuring an analyte in a sample with excellent sensitivity using a redox reaction is provided. In this method, a reducing substance or an oxidizing substance derived from the analyte is measured in the presence of a tetrazolium compound and sodium azide using the redox reaction, and an amount of the analyte is determined from the amount of the reducing substance or oxidizing substance thus measured. The tetrazolium compound and the sodium azide are present at a ratio in a range from 20:3 to 20:12. Preferably, a solution containing the tetrazolium compound and the sodium azide is aged and then added to the sample.

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 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 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: A method of measuring an analyte in a sample with excellent sensitivity using a redox reaction is provided. In this method, a reducing substance or an oxidizing substance derived from the analyte is measured in the presence of a tetrazolium compound and sodium azide using the redox reaction, and an amount of the analyte is determined from the amount of the reducing substance or oxidizing substance thus measured. The tetrazolium compound and the sodium azide are present at a ratio in a range from 20:3 to 20:12. Preferably, a solution containing the tetrazolium compound and the sodium azide is aged and then added to the sample.

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 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 producing a protein degradation product is provided, by which a protein (including a peptide) in a sample can be degraded quickly and efficiently. A sample containing a protein is treated with a protease in the presence of the tetrazolium compound to give a protein degradation product. Further, by causing a redox reaction between the glycation site of a glycated protein degradation product obtained by this method and a fructosyl amino acid oxidase, and then determining this redox reaction, it is possible to determine the amount of a glycated protein quickly. As the tetrazolium compound, 2-(4-iodophenyl)-3-(2,4-dinitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium salt etc. can be used.

Abstract: A sample containing a glycated protein is treated with Protease XIV or a protease from Aspergillus genus, thereafter (or while treating the sample with the above protease) FAOD (fructosyl amino acid oxidase) is caused to react with the sample so as to measure the amount of oxygen consumed by the FAOD reaction or the amount of the resultant reaction product, thereby to measure the glycated protein.According to the above method, the glycated protein can be fragmented while the decomposition of the FAOD itself is prevented, thereby to facilitate the binding of the protein with the FAOD and to improve the sensitivity of the detection.

Abstract: The present invention relates to a fructosyl amino acid oxidase that is obtainable from a culture of a strain of the genus Aspergillus. This strain grows in a selective medium containing at least either of fructosyl lysine and fructosyl-N.sup..alpha. -Z-lysine and is capable of producing a fructosyl amino acid oxidase.

Abstract: The present invention provides a polypeptide represented by the following amino acid sequence:(Met)n=X=Leu=Ala=Gly=Glu=Ile=Ala=Gly=Val=Asn - Trp=Glu=Ser - Gly=Tyr=Leu=Val=Gly=Ile=Lys=Arg=Gln=Arg=Arg - Leu=Tyr=Cys=Asn - Val=Gly=Ile=Gly=Phe=His=Leu=Gln=Val=Leu=Pro - Asp=Gly=Arg=Ile - Ser=Gly=Thr=His=Glu=Glu=Asn=Pro=Tyr=Ser=Leu - Leu=Glu=Ile=Ser - Thr=Val=Glu=Arg=Gly=Val=Val=Ser=Leu=Phe=Gly - Val=Arg=Ser=Ala - Leu=Phe=Val=Ala=Met=Asn=Ser=Lys=Gly=Arg=Leu - Tyr=Ala=Thr=Pro - Ser=Phe=Gin=Glu=Glu=Cys=Lys=Phe=Arg=Glu=Thr Leu=Leu=Pro=Asn - Asn=Tyr=Asn=Ala=Tyr=Glu=Ser=Asp=Leu=Tyr=Gln - Gly=Thr=Tyr=Ile - Ala=Leu=Ser=Lys=Tyr=Gly=Arg=Val=Lys=Arg=Gly - Ser=Lys=Val=Ser - Pro=Ile=Met=Thr=Val=Thr=His=Phe=Leu=Pro=Arg=Ile wherein n is 0 or 1 and X represents Pro Ala Gly Thr Arg Ala Asn Asn Thr Leu Leu Asp Ser Arg Gly Trp Gly Thr Leu Leu Ser Arg Ser Arg Ala Gly or a fragment thereof (n=0: SEQ ID NO: 1, n=1: SEQ ID NO: 2), a recombinant DNA coding for the polypeptide, a vector containing the recombinant DNA, the preparation of a