Kikkoman Corporation

Kozo Hirokawa

Atsushi Ichiyanagi

Naoki Kajiyama

Keiko Kurosawa

Ryoko Tajima

Yasuko Tanabe

Yosuke Masakari

Eriko Yoshihara

Seiji Murakami

Keiichi Ichikawa

Kazuhiko Shimoji

Yasuko Araki

Masanobu Yuzuki

This invention provides an amadoriase having high substrate specificity to fructosyl valyl histidine. Such amadoriase comprises substitution of one or more amino acid residues at positions corresponding to amino acids selected from the group consisting of position 98, position 259, position 154, position 125, position 261, position 263, position 106, position 103, position 355, position 96, position 66, position 67, position 70, position 100, position 110, position 113, position 114, and position 156 in the amadoriase derived from the genus. This invention enables accurate measurement of &#x3b1;-fructosyl valyl histidine derived from the &#x3b2;-chain amino terminus in glycated hemoglobin in the presence of &#x3b5;-fructosyl lysine.

Amadoriase having altered substrate specificity

A flavin-binding glucose dehydrogenase having high substrate specificity for D-glucose and decreased reactivity to D-xylose and/or maltose. More specifically, a flavin-binding glucose dehydrogenase having one or more amino acid substitutions at a position corresponding to position 78, position 79, position 81, position 121, position 122, position 123, position 569 and position 612 of Mucor-derived flavin-binding glucose dehydrogenase. The flavin-binding glucose dehydrogenase enables D-glucose to be measured accurately without being susceptible to the effects of the presence of D-xylose and/or maltose, even under conditions of mounting a large amount of an enzyme such as in glucose sensors.

Flavin-binding glucose dehydrogenase having improved substrate specificity

A heat-resistant flavin-bound glucose dehydrogenase having a high substrate specificity for D-glucose, an method for producing the same, and a transformant used for the same. A flavin-bound glucose dehydrogenase gene encoding a flavin-bound glucose dehydrogenase derived fromis introduced into yeast,, to obtain a transformant. Subsequently, the yeast transformant is cultured to obtain a flavin-bound glucose dehydrogenase from the culture. The heat-resistant flavin-bound glucose dehydrogenase is less susceptible to the effects of dissolved oxygen and allows accurate measurement of glucose even in the presence of sugar compounds other than glucose in a sample.

Flavin-bound glucose dehydrogenases, a method for producing a flavin-bound glucose dehydrogenase, and yeast transformant used for the same

A flavin-bound glucose dehydrogenase (FAD-GDH) with high substrate specificity for D-glucose. A gene encoding a mutant FAD-GDH with its N-terminal region, containing an amino acid sequence corresponding to MKITAAIITVATAFASFASA that exists in the N-terminal region, deleted from the amino acid sequence of a wild-type FAD-GDH derived fromis introduced intoto obtain antransformant. Subsequently, thistransformant is cultured to obtain an FAD-GDH with a specific N-terminal region deleted. The transformant allows the production of a large amount of GDH in a short time as compared with the original microorganism. An FAD-GDH that is less susceptible to the effects of dissolved oxygen and allows accurate measurement of glucose even in the presence of sugar compounds other than glucose in a sample.

[object Object]

A flavin-binding glucose dehydrogenase (FAD-GDH), which in addition to having high substrate specificity and adequate desirable heat stability, is suitable for efficient production, preferably using, yeast or molds and the like as host cells. The FAD-GDH has amino acid substitutions at positions equivalent to one or more locations selected from the group consisting of position 213, position 368 and position 526 in the amino acid sequence described in SEQ ID NO: 8. The FAD-GDH is acquired from a culture by inserting a gene encoding the FAD-GDH into host cells such as. A preferable example of the FAD-GDH is FAD-GDH, in which a signal peptide region present in an N-terminal region has been deleted from the amino acid sequence of Mucor-derived FAD-GDH, and which has the aforementioned amino acid substitutions. The FAD-GDH can be preferably used in clinical diagnosis.

Flavin-binding glucose dehydrogenase, method for producing flavin-binding glucose dehydrogenase, and glucose measurement method

Disclosed are: a eukaryotic amadoriase which is prepared by introducing a mutation into DNA encoding a eukaryotic amadoriase derived from a microorganism belonging to the genusorso as to introduce a substitution into a specific amino acid residue in the eukaryotic amadoriase, thereby overcoming the defect associated with thermal stability; a gene or recombinant DNA for the eukaryotic amadoriase; and a process for production of a eukaryotic amadoriase having excellent thermal stability.

Eukaryotic amadoriase, gene and recombinant DNA for the eukaryotic amadoriase, and process for production of the eukaryotic amadoriase

The present invention relates to a method for quantitative determination of an &#x3b1;-glycated peptide in a sample, comprising causing protease to act on a whole blood and/or blood cell sample, causing an elimination reagent containing one or a plurality of types of ketoamine oxidase to act on the resultant, eliminating an &#x3b1;-glycated amino acid, an &#x3b5;-glycated amino acid, an &#x3b5;-glycated peptide, or a combination thereof, and then determining the &#x3b1;-glycated peptide in the sample using oxidase that acts on the &#x3b1;-glycated peptide. The present invention also relates to an elimination reagent and a kit to be used for such method. According to the present invention, measurement errors in quantitative determination of a glycated protein such as glycated hemoglobin can be reduced, and thus a precise measured value can be obtained.

Method for quantitative determination of glycated protein and kit for quantitative determination of the same

Eukaryotic amadoriase having excellent thermal stability, gene and recombinant DNA for the eukaryotic amadoriase, and process for production of eukaryotic amadoriase having excellent thermal stability

The present invention has an object of providing a novel fructosyl peptide oxidase having superior physicochemical properties such as stability that is useful as an enzyme for clinical diagnosis, and an object of providing a method for producing the fructosyl peptide oxidase. A novel fructosyl peptide oxidase having physicochemical properties useful as an enzyme for clinical diagnosis, and a method for producing a novel fructosyl peptide oxidase are provided herein, the method comprising: culturing a microorganism capable of producing the oxidase in a medium; and collecting the oxidase from the culture. Furthermore, a fructosyl peptide oxidase gene coding for a novel fructosyl peptide oxidase, recombinant DNA wherein the gene is inserted into vector DNA, and a method for producing a novel fructosyl peptide oxidase are provided herein, the method comprising: culturing, in a medium, a transformant or a transductant including the gene; and collecting the novel fructosyl peptide oxidase from the culture.

Fructosyl peptide oxidase

The present invention relates to: an isolated or synthesized gene, which encodes a protein comprising the amino acid sequence represented by SEQ ID NO: 2, an isolated or synthesized gene, which encodes a protein comprising an amino acid sequence comprising a deletion, substitution or addition of one or more amino acids with respect to the amino acid sequence represented by SEQ ID NO: 2 and being capable of regenerating luciferin, an isolated or synthesized gene, which hybridizes with the complementary strand sequence of a DNA comprising the nucleotide sequence represented by SEQ ID NO: 1 under stringent conditions and encodes a protein capable of regenerating luciferin, a recombinant DNA, which is characterized in that the above-described isolated or synthesized gene is inserted into a vector DNA, a transformant or transductant comprising the above-described recombinant DNA, and a process for producing a protein capable of regenerating luciferin, which is characterized in that the method comprises culturing the above-described transformant or transductant in a medium and collecting therefrom the protein capable of regenerating luciferin.

Genes encoding proteins capable of regenerating luciferin, recombinant DNA and process for producing protein capable of regenerating luciferin

Gene encoding protein capable of regenerating luciferin, recombinant DNA and process for producing protein capable of regenerating luciferin

According to the present invention, there can be provided a bioluminescent protein, luciferase excellent in thermostability etc. and with high catalytic efficiency.

Growing community of inventors

Chiba, Japan

Kozo Hirokawa