Abstract: An object of the present invention is to provide a method for industrially producing a branched glucan having a cyclic structure. The method for producing a branched glucan having a cyclic structure comprises the steps of: (1) preparing a mixed liquid which contains a branching enzyme in which starch granules are suspended at a concentration of 5% by weight or more and 50% by weight or less, and allowing the branching enzyme to act on starch in the starch granules, wherein a temperature of the mixed liquid at the time of preparation is 0° C. or higher and not higher than the gelatinization starting temperature of the starch granule; and (2) elevating the temperature of the mixed liquid to 85° C. or higher and 129° C. or lower, wherein in the method, none of ?-amylase, ?-amylase, amyloglucosidase and ?transglucosidase is added to the mixed liquid.

Abstract: An object of the present invention is to provide a method for industrially producing a branched glucan having a cyclic structure. The method for producing a branched glucan having a cyclic structure comprises the steps of: (1) preparing a mixed liquid which contains a branching enzyme in which starch granules are suspended at a concentration of 5% by weight or more and 50% by weight or less, and allowing the branching enzyme to act on starch in the starch granules, wherein a temperature of the mixed liquid at the time of preparation is 0° C. or higher and not higher than the gelatinization starting temperature of the starch granule; and (2) elevating the temperature of the mixed liquid to 85° C. or higher and 129° C. or lower, wherein in the method, none of ?-amylase, ?-amylase, amyloglucosidase and a transglucosidase is added to the mixed liquid.

Abstract: An object of the present invention is to provide a glucosamine-containing glucan, a modified product and a conjugate thereof. The glucosamine-containing glucan of the present invention is a glucosamine-containing glucan wherein the glucan has a plurality of non-reducing ends and at least one glucosamine residue is bound via an ?-1,4-bond to each of two or more non-reducing ends of the branched ?-1,4-glucan, but no glucosamine residue is present at a position other than the non-reducing ends of the branched ?-1,4-glucan, wherein the degree of polymerization of the glucan is 15 or more and 4×105 or less. The glucosamine-containing glucan of the present invention can be provided by allowing an ?-glucan phosphorylase to act on an aqueous solution comprising a branched ?-1,4-glucan and glucosamine-1-phosphate.

Abstract: An object of the present invention is to provide a glucan containing at least one residue selected from an N-acetylglucosamine residue and a galactose residue, and a modified product. The branched glucan of the present invention is a branched glucan wherein the branched glucan has a plurality of non-reducing ends and at least one residue selected from an N-acetylglucosamine residue and a galactose residue is bound via an ?-1,4-bond to each of two or more non-reducing ends of the branched ?-1,4-glucan, but neither an N-acetylglucosamine residue nor a galactose residue is present at the position other than the non-reducing ends of the branched ?-1,4-glucan.

Abstract: An object of the present invention is to provide a uronic acid-containing glucan or a modified product thereof. The glucuronic acid-containing glucan of the present invention is a glucuronic acid-containing glucan in which a glucuronic acid residue is bound to at least one non-reducing end of a glucan, and the glucan is a branched ?-1,4 glucan or a linear ?-1,4 glucan. The glucuronic acid-containing glucan of the present invention can be provided by allowing ?-glucan phosphorylase derived from Aquifex aeolicus VF5 to act on glucuronic acid-1-phosphate to thereby transfer a glucuronic acid residue to the non-reducing end of the receptor glucan.

Abstract: An object of the present invention is to provide a uronic acid-containing glucan or a modified product thereof. The glucuronic acid-containing glucan of the present invention is a glucuronic acid-containing glucan in which a glucuronic acid residue is bound to at least one non-reducing end of a glucan, and the glucan is a branched ?-1,4 glucan or a linear ?-1,4 glucan. The glucuronic acid-containing glucan of the present invention can be provided by allowing ?-glucan phosphorylase derived from Aquifex aeolicus VF5 to act on glucuronic acid-1-phosphate to thereby transfer a glucuronic acid residue to the non-reducing end of the receptor glucan.

Abstract: A sucrose phosphorylase (SP) having improved thermostability obtained by modifying a natural SP and a method for producing the SP having improved thermostability is provided. This SP having improved thermostability has an amino acid residue which is different from that of the natural sucrose phosphorylase, in at least one position selected from the group consisting of a position corresponding to position 14, a position corresponding to position 29 and a position corresponding to position 44 in motif sequence 1; a position corresponding to position 7, a position corresponding to position 19, a position corresponding to position 23 and a position corresponding to position 34 in motif sequence 2; and a position corresponding to position 19 in motif sequence 3, and wherein the enzyme activity of the SP having improved thermostability at 37° C., after heating the SP having improved thermostability in 20 mM Tris buffer (pH 7.0) at 55° C.

Abstract: An ?-glucan phosphorylase having improved thermostability, which obtained by modifying natural ?-glucan phosphorylase, and a method for producing this ?-glucan phosphorylase having improved thermostability are provided. The natural ?-glucan phosphorylase is derived from a plant, this ?-glucan phosphorylase having improved thermostability has an amino acid residue which is different from that of the natural ?-glucan phosphorylase in at least one position selected from the group consisting of a position corresponding to position 4 in a motif sequence 1L or 1H, a position corresponding to position 4 in a motif sequence 2, and a position corresponding to position 7 in a motif sequence 3L or 3H, and wherein the enzyme activity of ?-glucan phosphorylase having improved thermostability at 37° C., after heating in a 20 mM citrate buffer (pH 6.7) at 60° C. for 10 minutes, is 20% or more of the enzyme activity of the ?-glucan phosphorylase having improved thermostability at 37° C., before heating.

Abstract: An ?-glucan phosphorylase having improved thermostability, which obtained by modifying natural ?-glucan phosphorylase, and a method for producing this ?-glucan phosphorylase having improved thermostability are provided. The natural ?-glucan phosphorylase is derived from a plant, this ?-glucan phosphorylase having improved thermostability has an amino acid residue which is different from that of the natural ?-glucan phosphorylase in at least one position selected from the group consisting of a position corresponding to position 4 in a motif sequence 1L or 1H, a position corresponding to position 4 in a motif sequence 2, and a position corresponding to position 7 in a motif sequence 3L or 3H, and wherein the enzyme activity of ?-glucan phosphorylase having improved thermostability at 37° C., after heating in a 20 mM citrate buffer (pH 6.7) at 60° C. for 10 minutes, is 20% or more of the enzyme activity of the ?-glucan phosphorylase having improved thermostability at 37° C., before heating.

Abstract: An ?-glucan phosphorylase having improved thermostability, which obtained by modifying natural ?-glucan phosphorylase, and a method for producing this ?-glucan phosphorylase having improved thermostability are provided. The natural ?-glucan phosphorylase is derived from a plant, this ?-glucan phosphorylase having improved thermostability has an amino acid residue which is different from that of the natural ?-glucan phosphorylase in at least one position selected from the group consisting of a position corresponding to position 4 in a motif sequence 1L or 1H, a position corresponding to position 4 in a motif sequence 2, and a position corresponding to position 7 in a motif sequence 3L or 3H, and wherein the enzyme activity of ?-glucan phosphorylase having improved thermostability at 37° C., after heating in a 20 mM citrate buffer (pH 6.7) at 60° C. for 10 minutes, is 20% or more of the enzyme activity of the ?-glucan phosphorylase having improved thermostability at 37° C., before heating.

Abstract: A sucrose phosphorylase (SP) having improved thermostability obtained by modifying a natural SP and a method for producing the SP having improved thermostability is provided. This SP having improved thermostability has an amino acid residue which is different from that of the natural sucrose phosphorylase, in at least one position selected from the group consisting of a position corresponding to position 14, a position corresponding to position 29 and a position corresponding to position 44 in motif sequence 1; a position corresponding to position 7, a position corresponding to position 19, a position corresponding to position 23 and a position corresponding to position 34 in motif sequence 2; and a position corresponding to position 19 in motif sequence 3, and wherein the enzyme activity of the SP having improved thermostability at 37° C., after heating the SP having improved thermostability in 20 mM Tris buffer (pH 7.0) at 55° C.

Abstract: A first method for producing glucan comprises the step of allowing a reaction solution containing sucrose, a primer, inorganic phosphate or glucose-1-phosphate, sucrose phosphorylase, and glucan phosphorylase to react to produce glucans. The maximum value of the sucrose-phosphate ratio of the reaction solution from the start of the reaction to the end of the reaction is no more than about 17. A second method for producing glucan comprises the step of allowing a reaction solution containing sucrose, a primer, inorganic phosphate or glucose-1-phosphate, sucrose phosphorylase, and glucan phosphorylase to react to produce glucans. The reaction is conducted at a temperature of about 40 C to about 70 C.

Abstract: An ?-glucan phosphorylase having improved thermostability, which obtained by modifying natural ?-glucan phosphorylase, and a method for producing this ?-glucan phosphorylase having improved thermostability are provided. The natural ?-glucan phosphorylase is derived from a plant, this ?-glucan phosphorylase having improved thermostability has an amino acid residue which is different from that of the natural ?-glucan phosphorylase in at least one position selected from the group consisting of a position corresponding to position 4 in a motif sequence 1L or 1H, a position corresponding to position 4 in a motif sequence 2, and a position corresponding to position 7 in a motif sequence 3L or 3H, and wherein the enzyme activity of ?-glucan phosphorylase having improved thermostability at 37° C., after heating in a 20 mM citrate buffer (pH 6.7) at 60° C. for 10 minutes, is 20% or more of the enzyme activity of the ?-glucan phosphorylase having improved thermostability at 37° C., before heating.

Abstract: A first method for producing glucan comprises the step of allowing a reaction solution containing sucrose, a primer, inorganic phosphate or glucose-1-phosphate, sucrose phosphorylase, and glucan phosphorylase to react to produce glucans. The maximum value of the sucrose-phosphate ratio of the reaction solution from the start of the reaction to the end of the reaction is no more than about 17. A second method for producing glucan comprises the step of allowing a reaction solution containing sucrose, a primer, inorganic phosphate or glucose-1-phosphate, sucrose phosphorylase, and glucan phosphorylase to react to produce glucans. The reaction is conducted at a temperature of about 40 C to about 70 C.

Abstract: Glucan with a degree of polymerization of 50 or more includes an inner branched cyclic structure portion and an outer branched structure portion, and methods for producing the same.

Abstract: An enzyme is altered by introducing an additional hydrophobic group to enhance the hydrophobic environment in the enzyme so as to interfere with entrance of a water molecule. In this connection, the site of introduction and kind of hydrophobic group to be introduced are selected on the basis of comprehensive analysis of amino acid sequence, three-dimensional structure, reaction mechanism or the like of the target enzyme. Using this method, an amino acid residue of neopullulanase derived from Bacillus stearothermophilus was replaced by another amino acid.

Abstract: The present invention provides glucans and derivatives thereof which are useful as raw materials in the starch processing industries, food and drink compositions, food additive compositions, and starch substitutes for biodegradable plastics, and processes for preparing the same. Particularly, it provides glucans and derivatives thereof having excellent properties such as higher solubility in water than conventional starches, lower viscosity and the glucans are not subject to retrogradation which is observed in conventional starches, and which are capable of preventing the retrogradation of starches.

Abstract: The present invention provides glucans and derivatives thereof which are useful as raw materials in the starch processing industries, food and drink compositions, food additive compositions, and starch substitutes for biodegradable plastics, and processes for preparing the same. Particularly, it provides glucans and derivatives thereof having excellent properties such as higher solubility in water than conventional starches, lower viscosity and the glucans are not subject to retrogradation which is observed in conventional starches, and which are capable of preventing the retrogradation of starches.