Abstract: Provided is a purified lactic acid-glycolic acid copolymer, preferably in the form of powder, having a reduced content of dimers such as residual lactide and glycolide that can be produced by a simple industrial process without the use of any high-shear special device. Further provided is a high-purity lactic acid-glycolic acid copolymer which has small amounts of dimers such as residual lactide and glycolide and small amounts of a low-molecular weight lactic acid-glycolic acid copolymer or a salt thereof and which has a small ratio of weight average molecular weight to number average molecular weight (Mw/Mn). The copolymer can be produced in accordance with a defined process.

Abstract: Provided is a purified lactic acid-glycolic acid copolymer, preferably in the form of powder, having a reduced content of dimers such as residual lactide and glycolide that can be produced by a simple industrial process without the use of any high-shear special device. Further provided is a high-purity lactic acid-glycolic acid copolymer which has small amounts of dimers such as residual lactide and glycolide and small amounts of a low-molecular weight lactic acid-glycolic acid copolymer or a salt thereof and which has a small ratio of weight average molecular weight to number average molecular weight (Mw/Mn). The copolymer can be produced in accordance with a defined process.

Abstract: The invention provides a method for producing a cytosine nucleoside compound from pentose-1-phosphate and cytosine or a derivative thereof using a nucleoside phosphorylase reactive to cytosine or a bacterium having the enzyme activity. The invention also provides a method for specifically reducing an activity to degrade the substrates or the product, resulting in efficient production of the cytosine nucleoside compound. According to the invention, little by-product is produced in producing cytonucleocide compounds.

Abstract: A novel gluconate dehydratase derived from Achromobacter xylosoxidans and a gene encoding the gluconate dehydratase are provided. By reacting the gluconate dehydratase or a transformed cell containing the gene with an aldonic acid, the corresponding 2-keto-3-deoxyaldonic acid can be efficiently produced.

Abstract: A novel gluconate dehydratase derived from Achromobacter xylosoxidans and a gene encoding the gluconate dehydratase are provided. By reacting the gluconate dehydratase or a transformed cell containing the gene with an aldonic acid, the corresponding 2-keto-3-deoxyaldonic acid can be efficiently produced.

Abstract: A novel gluconate dehydratase derived from Achromobacter xylosoxidans and a gene encoding the gluconate dehydratase are provided. By reacting the gluconate dehydratase or a transformed cell containing the gene with an aldonic acid, the corresponding 2-keto-3-deoxyaldonic acid can be efficiently produced.

Abstract: The invention provides a method for producing a cytosine nucleoside compound from pentose-1-phosphate and cytosine or a derivative thereof using a nucleoside phosphorylase reactive to cytosine or a bacterium having the enzyme activity. The invention also provides a method for specifically reducing an activity to degrade the substrates or the product, resulting in efficient production of the cytosine nucleoside compound. According to the invention, little by-product is produced in producing cytonucleocide compounds.

Abstract: A protected 2?-deoxycytidine is purified by precipitating the protected 2?-deoxycytidine represented by general formula (3) in the form of a hydrated crystal from a solution containing the protected 2?-deoxycytidine and water, and by recovering the protected 2?-deoxycytidine: wherein R1 represents a 4-methoxytrityl, 4, 4?-dimethoxytrityl, or triphenylmethyl group; and B1 represents a cytosine group having a protected amino group. The compound represented by general formula (3) is, in particular, a protected 2?-deoxycytidine represented by formula (4): The 2?-deoxycytidine is used as a raw material for antisense DNA.

Abstract: A novel gluconate dehydratase derived from Achromobacter xylosoxidans and a gene encoding the gluconate dehydratase are provided. By reacting the gluconate dehydratase or a transformed cell containing the gene with an aldonic acid, the corresponding 2-keto-3-deoxyaldonic acid can be efficiently produced.

Abstract: The invention provides a method for producing a cytosine nucleoside compound from pentose-1-phosphate and cytosine or a derivative thereof using a nucleoside phosphorylase reactive to cytosine or a bacterium having the enzyme activity. The invention also provides a method for specifically reducing an activity to degrade the substrates or the product, resulting in efficient production of the cytosine nucleoside compound. According to the invention, little by-product is produced in producing cytonucleocide compounds.

Abstract: An aldose having n-1 carbon atoms is produced from an aldonic acid having n carbon atoms using hypochlorous acid or a hypochlorite in a high yield at low cost with safety, by treating the reaction mixture with a compound having reactivity with the hypochlorous acid or hypochlorite higher than that with the produced aldose.

Abstract: In reacting pentose-1-phosphoric acid with a nucleic acid base or a nucleic acid base analogue in an aqueous reaction medium in the presence of a metal cation to produce a nucleoside compound, the timing or method of addition of at least one of these components to the aqueous reaction medium is varied; thereby, a nucleoside compound can be produced at a high yield efficiently without inviting the high viscosity or solidification of the reaction mixture, even when the above components are used in such amounts that the reaction mixture becomes highly viscous or is solidified when the components are used without the above variation of the addition timing or method. Thus, there can be provided a process for producing a nucleoside compound, which comprises a step of reacting pentose-1-phosphoric acid with a nucleic acid base or a nucleic acid base analogue in the presence of nucleoside phosphorylase activity, which gives a nucleoside compound at an improved conversion, and which has wide applicability.

Abstract: A protected 2′-deoxycytidine is purified by precipitating the protected 2′-deoxycytidine represented by general formula (3) in the form of a hydrated crystal from a solution containing the protected 2′-deoxycytidine and water, and by recovering the protected 2′-deoxycytidine: 1

Abstract: The invention provides a method for producing a cytosine nucleoside compound from pentose-1-phosphate and cytosine or a derivative thereof using a nucleoside phosphorylase reactive to cytosine or a bacterium having the enzyme activity. The invention also provides a method for specifically reducing an activity to degrade the substrates or the product, resulting in efficient production of the cytosine nucleoside compound. According to the invention, little by-product is produced in producing cytonucleocide compounds.