摘要:
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. for 20 minutes, is 20% or more of enzyme activity of the SP having improved thermostability at 37° C. before heating.
摘要:
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. for 20 minutes, is 20% or more of enzyme activity of the SP having improved thermostability at 37° C. before heating.
摘要:
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.
摘要:
An α-glucan phosphorylase having improved thermostability, which obtained by modifying natural α-glucan phosphorylase, and a method for producing this α-glucan phosphorylase having improved thermostability are provided. The natural α-glucan phosphorylase is derived from a plant, this α-glucan phosphorylase having improved thermostability has an amino acid residue which is different from that of the natural α-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 α-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 α-glucan phosphorylase having improved thermostability at 37° C., before heating.
摘要:
An α-glucan phosphorylase having improved thermostability, which obtained by modifying natural α-glucan phosphorylase, and a method for producing this α-glucan phosphorylase having improved thermostability are provided. The natural α-glucan phosphorylase is derived from a plant, this α-glucan phosphorylase having improved thermostability has an amino acid residue which is different from that of the natural α-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 α-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 α-glucan phosphorylase having improved thermostability at 37° C., before heating.
摘要:
An α-glucan phosphorylase having improved thermostability, which obtained by modifying natural α-glucan phosphorylase, and a method for producing this α-glucan phosphorylase having improved thermostability are provided. The natural α-glucan phosphorylase is derived from a plant, this α-glucan phosphorylase having improved thermostability has an amino acid residue which is different from that of the natural α-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 α-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 α-glucan phosphorylase having improved thermostability at 37° C., before heating.
摘要:
An α-glucan phosphorylase having improved thermostability, which obtained by modifying natural α-glucan phosphorylase, and a method for producing this α-glucan phosphorylase having improved thermostability are provided. The natural α-glucan phosphorylase is derived from a plant, this α-glucan phosphorylase having improved thermostability has an amino acid residue which is different from that of the natural α-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 α-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 α-glucan phosphorylase having improved thermostability at 37° C., before heating.
摘要:
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.
摘要:
A disintegrant for tablets consisting of an α-1,4-glucan having a degree of polymerization of not less than 180 and less than 1230 and a dispersity (weight average molecular weight “Mw”/number average molecular weight “Mn”) of not more than 1.25 or a modified product thereof. A binder for tablets consisting of an α-1,4-glucan having a degree of polymerization of not less than 1230 and not more than 37000 and a dispersity of not more than 1.25, or a modified product thereof. A binding-disintegrating agent for tablets consisting of a low molecular weight α-1,4-glucan or a modified product thereof, and a high molecular weight α-1,4-glucan or a modified product thereof, wherein the low molecular weight α-1,4-glucan has a degree of polymerization of not less than 180 and less than 1230 and a dispersity of not more than 1.25, and wherein the high molecular weight α-1,4-glucan has a degree of polymerization of not less than 1230 and not less than 37000 and a dispersity of not more than 1.25.
摘要:
The present invention discloses a molded article containing high molecular weight α-1,4-glucan and/or its modification, and low molecular weight α-1,4-glucan and/or its modification. The low molecular weight α-1,4-glucan has the degree of polymerization of greater than or equal to 180 and less than 620. And the high molecular weight α-1,4-glucan has the degree of polymerization of greater than or equal to 620 and less than 37000. The high molecular weight α-1,4-glucan may preferably have a molecular weight distribution of not greater than 1.25, and the low molecular weight α-1,4-glucan may preferably have a molecular weight distribution of not greater than 1.25. The present invention also discloses a process for preparing the molded article, wherein the process comprises the step of adding the low molecular weight α-1,4-glucan and/or its modification to a solution comprising the high molecular weight α-1,4-glucan and/or its modification to gel the solution.