Arkray, Inc.

Kyoto Daiichi Kagaku Co., Ltd.

Kaori Ishimaru

Satoshi Yonehara

Masayuki Yagi

Nobuo Kato

Yoshiki Tani

Yasuyoshi Sakai

Hiroshi Fukuya

Toshikatsu Sakai

Kaoru Hirai

Tsuguki Komori

Miki Horii

Katsutaka Ooishi

Akihiko Okamura

Satoshi Cyousa

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.

Method for storing tetrazolium compound, stabilizer used in the same, and tetrazolium compound reagent solution using the method

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.

Method of quantifying glycosylated protein using redox reaction and quantification kit

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.

Method of decomposing protein with sulfonic acid compound

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.

Method of assay by oxidation-reduction reaction with formazan

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.

Method of assay with sulfonic acid compound and nitro compound

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.

Method for measurement using sodium azide

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 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.

&agr;-glycated amino acid releasing enzyme

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 KDK1002 (FERM P-17135) and 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.

Enzyme

Method of enzymatically measuring glycated protein

Fructosyl amino acid oxidase, process for producing the same, and method

A novel fructosyl amino acid oxidase derived from genus Fusarium, which is active on both of fructosyl lysine and fructosyl valine, a process for producing the enzyme, an assay of an amadori compound using the enzyme, a reagent or a kit containing the enzyme is provided.

Growing community of inventors

Kyoto, Japan

Kaori Ishimaru