Kabushiki Kaisha Hayashibara Seibutsu Kagaku Kenkyujo

Kazuhiko Maruta

Michio Kubota

Toshiyuki Sugimoto

Toshio Miyake

Shigeharu Fukuda

Takuo Yamamoto

Keiji Tsusaki

Hiroto Chaen

Tomoyuki Nishimoto

Tetsuya Nakada

Kozo Yamamoto

An object of the present invention is to provide a novel ketose 3-epimerase, a process for producing the same, a DNA encoding the enzyme, a recombinant DNA and transformant comprising the DNA, and a process for producing a ketose by using the enzyme. The present invention solves the above objects by providing a ketose 3-epimerase which is obtainable from a microorganism of the genus, a process for producing the same, a DNA encoding the enzyme, a recombinant DNA and transformant comprising the DNA, and a process for converting D- or L-ketohexose into corresponding D- or L-ketohexose by epimerizing the hydroxyl group at the C-3 position of the D- or L-ketohexose; and D- or L-ketopentose into corresponding D- or L-ketopentose by epimerizing the hydroxyl group at the C-3 position of the D- or L-ketopentose; by using the enzyme.

Ketose 3-epimerase, its preparation and uses

A non-reducing saccharide-forming enzyme and a trehalose-releasing enzyme, which have an optimum temperature in a medium temperature range, i.e., a temperature of over 40 or 45&#xb0; C. but below 60&#xb0; C.; and an optimum pH in an acid pH range, i.e., a pH of less than 7. The two-types of enzymes can be obtained in a desired amount, for example, by culturing in a nutrient culture medium microorganisms capable of producing the enzymes or by recombinant DNA technology.

Non-reducing saccharide-forming enzyme, trehalose-releasing enzyme, and process for producing saccharides using the enzymes

The object of the present invention is to provide a polypeptide which can be used to produce a saccharide having the structure of cyclo{&#x2192;6)-&#x3b1;-D-glucopyranosyl-(1&#x2192;3)-&#x3b1;-D-glucopyranosyl-(1&#x2192;6)-&#x3b1;-D-glucopyranosyl-(1&#x2192;3)-&#x3b1;-D-glucopyranosyl-(1&#x2192;}, a DNA encoding the polypeptide, and uses thereof. The present invention solves the above object by establishing a polypeptide which has an enzymatic activity of forming a saccharide with a glucose polymerization degree of 3 or higher and bearing both the &#x3b1;-1,6 glucosidic linkage as a linkage at the non-reducing end and the &#x3b1;-1,4 glucosidic linkage other than the linkage at the non-reducing end from a saccharide with a glucose polymerization degree of 2 or higher and bearing the &#x3b1;-1,4 glucosidic linkage as a linkage at the non-reducing end by &#x3b1;-glucosyl transferring reaction without substantially increasing the reducing power, a DNA encoding the polypeptide, a replicable recombinant DNA comprising the DNA encoding the polypeptide and an autonomously replicable vector, a transformant constructed by introducing the recombinant DNA into an appropriate host, and uses thereof.

Polypeptide having &#x3b1;-isomaltosylglucosaccharide synthase activity

The object of the present invention is to provide a polypeptide which can be used to produce a saccharide having a structure of cyclo{&#x2192;6)-&#x3b1;-D-glucopyranosyl-(1&#x2192;3)-&#x3b1;-D-glucopyranosyl-(1&#x2192;6)-&#x3b1;-D-glucopyranosyl-(1&#x2192;3)-&#x3b1;-D-glucopyranosyl-(1&#x2192;}, a DNA encoding the polypeptide, and uses thereof. The present invention solves the above object by establishing a polypeptide which has an enzymatic activity to produce a saccharide having a structure of cyclo{&#x2192;6}-&#x3b1;-D-glucopyranosyl-(1&#x2192;3)-&#x3b1;-D-glucopyranosyl-(1&#x2192;6)-&#x3b1;-D-glucopyranosyl-(1&#x2192;3)-&#x3b1;-D-glucopyranosyl-(1&#x2192;} from a saccharide with a glucose polymerization degree of 3 or higher and bearing both the &#x3b1;-1,6 glucosidic linkage as a linkage at the non-reducing end and the &#x3b1;-1,4 glucosidic linkage other than the linkage at the non-reducing end by catalyzing the &#x3b1;-isomaltosyl-transfer, and having an amino acid sequence of either SEQ ID NO:1 or SEQ ID NO:2, or that which is a member selected from the group consisting of amino acid sequences having deletion, replacement, or addition of one or more amino acid residues therein or thereto, a DNA encoding the polypeptide, and uses thereof.

Polypeptide having &#x3b1;-isomaltosyl-transferase activity

Disclosed are novel non-reducing saccharide-forming enzyme, and its preparation and uses. The enzyme is obtainable from the culture of microorganisms such as Rhizobium sp. M-11 (FERM BP 4130) and Arthrobacter sp. Q36 (FERM BP-4316), and capable of forming non-reducing saccharides having a trehalose structure when allowed to act on reducing partial starch hydrolysates. Glucoamylase and .alpha.-glucosidase readily yield trehalose when allowed to act on the non-reducing saccharides. These non-reducing saccharides and trehalose are extensively useful in food products, cosmetics and pharmaceuticals.

Non-reducing saccharide-forming enzyme, its preparation and uses

Disclosed is a recombinant thermostable enzyme which has a molecular weight of about 69,000-79,000 daltons and a pI of about 5.4-6.4, and forms non-reducing saccharides having a trehalose structure as an end unit from reducing amylaceous saccharides having a degree of glucose polymerization of at least 3. The enzyme has satisfactorily high thermostability, i.e. it is substantially not inactivated even when incubated in an aqueous solution (pH 7.0) at 85.degree. C. for 60 min, and this facilitates the production of such non-reducing saccharides on an industrial scale and in a satisfactorily-high yield.

Recombinant thermostable enzyme which forms non-reducing saccharide from

A DNA encoding an enzyme, which forms non-reducing saccharides having trehalose structure as an end unit from amylaceous saccharides having a degree of glucose polymerization of 3 or higher, enables an industrial-scale production of a recombinant enzyme with such enzyme activity. Non-reducing saccharides obtainable by the recombinant enzyme can be used in a variety of food products, cosmetics, pharmaceuticals and feeds because of their substantial non-reducibility, mild and high-quality sweetness, adequate viscosity, and moisture-retaining ability.

DNA encoding enzyme recombinant DNA and enzyme transformant, and their

DNA encoding enzyme, recombinant DNA and enzyme, transformant, and their

Disclosed are novel non-reducing saccharide-forming enzyme, and its preparation and uses. The enzyme is obtainable from the culture of microorganisms such as Rhizobium sp. M-11 (FERM BP 4130) and Arthrobacter sp. Q36 (FERM BP-4316), and capable of forming non-reducing saccharides having a trehalose structure when allowed to act-on reducing partial starch hydrolysates. Glucoamylase and .alpha.-glucosidase readily yield trehalose when allowed to act on the non-reducing saccharides. These non-reducing saccharides and trehalose are extensively useful in food products, cosmetics and pharmaceuticals.

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Okayama, Japan

Kazuhiko Maruta