JP2008029358A - Process for producing nucleoside compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide 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. <P>SOLUTION: A salt slightly soluble in water is used as a salt of a metal cation, when producing the nucleoside compound by reacting the pentose-1-phosphoric acid with the nucleic acid base or the nucleic acid base analogue in the presence of the nucleoside phosphorylase activity, and in the presence of the salt of the metal cation forming a slightly water-soluble salt with a phosphate ion without regulating the pH. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a nucleoside compound using nucleoside phosphorylase. Various nucleosides and analog compounds thereof are used as raw materials or raw materials for antiviral drugs, anticancer drugs, and antisense drugs.

  Nucleoside phosphorylase is a general term for enzymes that phosphorylate the N-glycoside bond of nucleoside in the presence of phosphoric acid, and catalyzes a reaction represented by the following formula when ribonucleoside is taken as an example.

Ribonucleoside + phosphate (salt) → nucleobase + ribose 1-phosphate purine nucleoside phosphorylase and pyrimidine nucleoside phosphorylase are broadly distributed in the biological kingdom, tissues such as mammals, birds and fish, yeast Present in bacteria. This enzymatic reaction is reversible, and the synthesis of various nucleoside compounds using reverse reactions has been known for some time.

  For example, from 2′-deoxyribose 1-phosphate and a nucleobase (thymine, adenine or guanine) to thymidine (JP 01-104190 A), 2′-deoxyadenosine (JP 11-137290 A) or 2 ′ A method for producing deoxyguanosine (Japanese Patent Laid-Open No. 11-137290) is known. Furthermore, in Agric., Biol., Chem., Vol. 50 (1)., PP. 121-126, (1986), inosine was reacted with a purine nucleoside phosphorylase derived from Enterobacter aerogenes in the presence of phosphoric acid. From ribose 1-phosphate and 1,2,4-triazole-3-carboxamide isolated by ion exchange resin after being decomposed into ribose 1-phosphate and hypoxanthine, purine nucleoside phosphorylase derived from Enterobacter aerogenes, A technique for producing ribavirin, an antiviral agent, has been reported.

However, since the reaction for producing a nucleoside compound from pentose-1-phosphate or a salt thereof and a nucleobase by utilizing the reverse reaction of the enzyme is an equilibrium reaction, it has a technical disadvantage that the conversion rate is not improved. It was.
Japanese Patent Laid-Open No. 01-104190 Japanese Patent Laid-Open No. 11-137290 Japanese Patent Laid-Open No. 11-137290 Agric., Biol., Chem., Vol. 50 (1)., PP. 121-126, (1986)

  The problem to be solved by the present invention is to provide a method that contributes to the reduction of raw material costs and the improvement of product purity by allowing the reaction to proceed at a high conversion rate when producing a nucleoside compound industrially. There is.

  That is, an object of the present invention is to have a step of reacting pentose-1-phosphate with a nucleobase or nucleobase analog in the presence of nucleoside phosphorylase activity, and the conversion rate of the nucleoside compound in the reaction is improved. Another object of the present invention is to provide a simple and versatile method for producing a nucleoside compound.

  As a result of intensive studies to solve these problems, the present inventors have found that when a metal cation capable of forming a poorly water-soluble salt with phosphate ion is present in the reaction solution, phosphate ion, which is a byproduct of the reaction, is present. It has been found that precipitation as a hardly water-soluble salt and exclusion from the reaction system shifts the reaction equilibrium in the direction of nucleoside compound synthesis and improves the reaction conversion rate.

  Furthermore, the present inventors have made a metal cation capable of forming a poorly water-soluble salt with phosphoric acid present in the reaction solution as a salt of pentose-1-phosphate, whereby the above-mentioned phosphoric acid and the poorly water-soluble salt are present. It has been found that the same effect can be obtained as when a metal cation capable of forming a salt or a salt thereof is added.

  In addition, the present inventors generally have low solubility and reactivity in a method for producing a nucleoside compound by exchanging pentose-1-phosphate with a phosphate group and a nucleobase or nucleobase analog in the presence of a nucleoside phosphorylase. It was found that a nucleoside compound can be obtained at a high conversion rate by introducing a nucleobase analog having a low molecular weight into the reaction system as an aqueous alkali metal solution to improve the substrate concentration during the reaction.

  Furthermore, in the production of the nucleoside compound, when an aqueous solution of a metal cation salt containing lithium ions or magnesium ions is used as the alkali metal aqueous solution, the phosphoric acid produced by the reaction is insolubilized as lithium phosphate or magnesium phosphate. It has been found that the nucleoside compound can be obtained with high selectivity and high yield, which could not be achieved by the prior art, by the equilibrium of the enzyme reaction being inclined toward the synthesis side of the nucleoside compound.

  In particular, when a metal cation salt that is sparingly soluble in water such as magnesium hydroxide is used as the metal cation salt that can form a sparingly water-soluble salt with phosphoric acid, the salt concentration of the reaction solution does not increase. The reduction in reaction rate caused by the increase in the reaction solution is prevented, and the total amount of such metal cation salts can be added before the reaction, so that the operation is simpler than when magnesium is added as a metal aqueous solution. In addition, it has also been found that there is an advantage that the filterability of the obtained reaction solution is remarkably improved.

  Furthermore, when magnesium hydroxide is used as the metal cation salt, crystals of magnesium phosphate, which is a poorly water-soluble phosphate obtained by the reaction, are relatively suitable in size and shape for filtration of the reaction solution. The present inventors have found that there is an advantage that filtration of the reaction solution after completion of the reaction is performed quickly.

  Furthermore, in order to industrially produce a nucleoside compound, it is desirable to accumulate the nucleoside compound at a high concentration in the reaction solution because of the need to improve volumetric efficiency and recovery during purification. In order to obtain a highly accumulated concentration of nucleoside compounds when a metal cation is present in the reaction solution as described above and reacted with phosphate ions generated as the reaction proceeds and precipitated as a poorly water-soluble salt. When the amount of the component is increased, if the pH of the reaction solution is too low as the phosphoric acid and the metal cation form a corresponding poorly water-soluble salt and precipitate, the reaction conversion rate decreases. The decrease in the reaction conversion rate due to the decrease in the pH of the reaction solution is considered to be due to the decomposition of the produced nucleoside compound or partial deactivation of the enzyme activity.

  In such a case, it is preferable to adjust the pH of the reaction solution in order to maintain the desired reaction conversion rate. However, if the initial charge (at the start of the reaction) is increased in order to obtain a high accumulated concentration of the nucleoside compound, the viscosity of the reaction solution increases as the reaction proceeds, and the reaction solution may solidify. It was. When the viscosity of the reaction solution is increased or solidified, it becomes difficult to adjust the desired pH described above. Further, when the viscosity of the reaction liquid increases, the power required for mixing and stirring the reaction liquid becomes excessive, which may cause equipment failure.

  The present inventors used at least a pentose-1-phosphate, a nucleobase or a nucleobase analog, and a metal cation when using a charge amount for obtaining a high accumulation concentration of a nucleoside compound in a reaction solution. It has been found that the viscosity or solidification of the reaction solution can be prevented by adding all or part of one charge amount at a predetermined time after the start of the reaction.

That is, the present invention made based on the above findings includes the following aspects.
[1] In an aqueous reaction medium, in the presence of nucleoside phosphorylase activity, pentose-1-phosphate and a nucleobase or a nucleobase analog of a metal cation capable of forming a poorly water-soluble salt with a phosphate ion A method for producing a nucleoside compound, which is reacted in the presence to form a nucleoside compound, and at least one selected from the pentose-1-phosphate, the nucleobase or nucleobase analog and the metal cation after the reaction starts A method for producing a nucleoside compound, comprising adding the above component to an aqueous reaction medium during the reaction.
[2] The method for producing a nucleoside compound according to the above [1], wherein the pentose-1-phosphate is ribose-1-phosphate or 2-deoxyribose-1-phosphate.
[3] The above [1], wherein the metal cation capable of forming a sparingly water-soluble salt with the phosphate ion is one or more selected from calcium ion, barium ion, aluminum ion, lithium ion and magnesium ion The method for producing a nucleoside compound according to [2].
[4] The metal cation capable of forming a poorly water-soluble salt with the phosphate ion is at least one anion selected from the group consisting of chloride ion, nitrate ion, carbonate ion, sulfate ion, acetate ion and hydroxide ion. The method for producing a nucleoside compound according to the above [3], wherein the nucleoside compound is added as a metal salt to an aqueous reaction medium.
[5] The method for producing a nucleoside compound according to the above [3], wherein a metal cation capable of forming a poorly water-soluble salt with the phosphate ion is added to the aqueous reaction medium as a salt of pentose-1-phosphate.
[6] Regarding at least one of the at least one component added to the aqueous reaction medium after the start of the reaction, the amount to be added by the end of the reaction is divided into two or more times or continuously gradually. The method for producing a nucleoside compound according to the above [1], which is added to the aqueous reaction medium.
[7] The amount of the pentose-1-phosphate, the nucleobase or nucleobase analog, and the three components of the metal cation added by the end of the reaction is added to the aqueous reaction medium in a batch. When the reaction is carried out, the aqueous reaction medium becomes highly viscous or solidified, and part or all of the addition amount of the one or more components after the start of the reaction until the end of the reaction is added separately after the start of the reaction. The method for producing a nucleoside compound according to the above [1] or [6], wherein the liquid is prevented from becoming highly viscous or solidified.
[8] The method for producing a nucleoside compound according to any one of [1] to [7], wherein the nucleobase or nucleobase analog is added as an alkaline aqueous solution.
[9] The above-mentioned [8], wherein the alkaline aqueous solution dissolving the nucleobase or nucleobase analog is a solution containing any one or more of lithium hydroxide, lithium carbonate and lithium hydrogen carbonate. A method for producing a nucleoside compound.
[10] A salt of a metal cation that forms a sparingly water-soluble salt with a phosphate ion in the presence of nucleoside phosphorylase activity in the presence of nucleoside phosphorylase activity and pentose-1-phosphate For producing a nucleoside compound by reacting without adjusting pH in the presence of water, wherein the metal cation salt is a poorly water-soluble salt in water. .
[11] The method for producing a nucleoside compound according to the above [10], wherein the metal cation salt is at least one selected from magnesium hydroxide, magnesium oxide, magnesium carbonate and basic magnesium carbonate.
[12] The method for producing a nucleoside compound according to the above [11], wherein the pH of the aqueous reaction medium during the reaction is in the range of 7.5 to 10.0.
[13] The nucleoside according to [11] above, which includes a step of filtering the reaction solution obtained by the reaction to remove insoluble substances in the reaction solution to obtain a filtrate containing a nucleoside compound. Compound production method.

  According to the present invention, in the production of a nucleoside compound from pentose-1-phosphate and a nucleobase using nucleoside phosphorylase or a microorganism having the enzyme activity, a metal salt capable of forming a poorly water-soluble salt with phosphate is added. By doing so, the phosphoric acid produced as a by-product is excluded from the reaction system, and an improvement in the reaction yield not achieved by the prior art is achieved. Moreover, it becomes possible to produce a nucleoside compound efficiently in a high yield without increasing the viscosity or solidification of the reaction solution. From the industrial point of view, the present invention leads to a significant cost reduction, and its significance is great.

  When the nucleobase or nucleobase analog is dissolved in an alkaline aqueous solution such as lithium hydroxide and added, the reaction operation becomes simple.

  When magnesium hydroxide is used as a metal cation salt capable of forming a poorly water-soluble salt with phosphate ion, the solubility of magnesium hydroxide in water is low. (1) The pH of the reaction solution hardly changes during the reaction. Therefore, inactivation of the enzyme is prevented (when a water-soluble metal cation salt other than magnesium hydroxide hydroxide is used, the pH of the reaction solution changes slightly to the alkaline side during the reaction). (2) Accompanying the reaction Since there is no increase in the salt concentration of the reaction solution, reaction inhibition due to an increase in the salt concentration is prevented, and a higher concentration reaction is possible. (3) Metal cations can be added all at once before the reaction, etc. There are advantages. In addition, when magnesium ions are used as the metal cation, the filtration rate is remarkably improved in the step of filtering the reaction solution after completion of the reaction, which is very useful industrially.

  The pentose-1-phosphate in the present invention is a compound in which phosphoric acid is ester-bonded to the 1-position of polyhydroxyaldehyde or polyhydroxyketone and its derivative. Typical examples include ribose 1-phosphate, 2′-deoxyribose 1-phosphate, 2 ′, 3′-dideoxyribose 1-phosphate, arabinose 1-phosphate, and the like. It is not limited.

  The polyhydroxyaldehyde or polyhydroxyketone as used herein is derived from natural products such as D-arabinose, L-arabinose, D-xylose, L-lyxose, aldopentose such as D-ribose, D-xylulose, Examples include, but are not limited to, ketopentoses such as L-xylulose and D-ribulose, and deoxysaccharides such as D-2-deoxyribose and D-2,3-dideoxyribose.

  These pentose-1-phosphates are produced by a method of producing a nucleoside phosphorolysis reaction by the action of nucleoside phosphorylase (J. Biol. Chem. Vol. 184, 437, 1950), anomeric selective chemistry, etc. It can also be prepared by a synthesis method or the like.

  The nucleobase used in the present invention is a heterocyclic compound containing a nitrogen atom that is a compound structural element of DNA or RNA, and is selected from the group consisting of pyrimidine, purine, and base analogs, natural or non-natural Type nucleobases, which are halogen atoms, alkyl groups, haloalkyl groups, alkenyl groups, haloalkenyl groups, alkynyl groups, amino groups, alkylamino groups, hydroxyl groups, hydroxyamino groups, aminooxy groups, alkoxy groups, mercapto Optionally substituted by a group, an alkyl mercapto group, an aryl group, an aryloxy group or a cyano group.

  Examples of the halogen atom as a substituent include chlorine, fluorine, iodine and bromine. Examples of the alkyl group include C1-C7 alkyl groups such as a methyl group, an ethyl group, and a propyl group. Examples of the haloalkyl group include haloalkyl groups having an alkyl group having 1 to 7 carbon atoms such as fluoromethyl, difluoromethyl, trifluoromethyl, bromomethyl and bromoethyl. Examples of the alkenyl group include C2-C7 alkenyl groups such as vinyl and allyl. Examples of the haloalkenyl group include haloalkenyl groups having 2 to 7 carbon atoms such as bromovinyl and chlorovinyl. Examples of the alkynyl group include alkynyl groups having 2 to 7 carbon atoms such as ethynyl and propynyl. Examples of the alkylamino group include alkylamino groups having a C1-7 alkyl group such as methylamino and ethylamino. Examples of the alkoxy group include C1-C7 alkoxy groups such as methoxy and ethoxy. Examples of the alkyl mercapto group include alkyl mercapto groups having an alkyl group having 1 to 7 carbon atoms such as methyl mercapto and ethyl mercapto. Examples of the aryl group include a phenyl group; an alkylphenyl group having an alkyl group having 1 to 5 carbon atoms such as methylphenyl and ethylphenyl; an alkoxyphenyl group having an alkoxy group having 1 to 5 carbon atoms such as methoxyphenyl and ethoxyphenyl; Examples thereof include alkylaminophenyl groups having 1 to 5 carbon atoms such as dimethylaminophenyl and diethylaminophenyl; halogenophenyl groups such as chlorophenyl and bromophenyl.

  Specific examples of the nucleobase having a pyrimidine skeleton include cytosine, uracil, 5-fluorocytosine, 5-fluorouracil, 5-chlorocytosine, 5-chlorouracil, 5-bromocytosine, 5-bromouracil, 5-yo -Docytosine, 5-yodouracil, 5-methylcytosine, 5-methyluracil (thymine), 5-ethylcytosine, 5-ethyluracil, 5-fluoromethylcytosine, 5-fluorouracil, 5-trifluorocytosine, 5- Trifluorouracil, 5-vinyluracil, 5-bromovinyluracil, 5-chlorovinyluracil, 5-ethynylcytosine, 5-ethynyluracil, 5-propynyluracil, pyrimidin-2-one, 4-hydroxyaminopyrimidin-2-one 4-aminooxypyrimidine-2-o , 4-methoxy-2-one, 4-acetoxy-2-one, 4-fluoro-2-one, and 5-fluoro-pyrimidin-2-one and the like.

  Specific examples of nucleobases having a purine skeleton include purine, 6-aminopurine (adenine), 6-hydroxypurine, 6-fluoropurine, 6-chloropurine, 6-methylaminopurine, and 6-dimethylaminopurine. 6-trifluoromethylaminopurine, 6-benzoylaminopurine, 6-acetylaminopurine, 6-hydroxyaminopurine, 6-aminooxypurine, 6-methoxypurine, 6-acetoxypurine, 6-benzoyloxypurine, 6 -Methylpurine, 6-ethylpurine, 6-trifluoromethylpurine, 6-phenylpurine, 6-mercaptopurine, 6-methylmercaptopurine, 6-aminopurine-1-oxide, 6-hydroxypurine-1-oxide, 2-amino-6-hydroxypurine (guanine), 2,6- Aminopurine, 2-amino-6-chloropurine, 2-amino-6-iodopurine, 2-aminopurine, 2-amino-6-mercaptopurine, 2-amino-6-methylmercaptopurine, 2-amino- 6-hydroxyaminopurine, 2-amino-6-methoxypurine, 2-amino-6-benzoyloxypurine, 2-amino-6-acetoxypurine, 2-amino-6-methylpurine, 2-amino-6-cyclo Propylaminomethylpurine, 2-amino-6-phenylpurine, 2-amino-8-bromopurine, 6-cyanopurine, 6-amino-2-chloropurine (2-chloroadenine), 6-amino-2-fluoro And purine (2-fluoroadenine).

  Specific examples of base analogs include 6-amino-3-deazapurine, 6-amino-8-azapurine, 2-amino-6-hydroxy-8-azapurine, 6-amino-7-deazapurine, 6-amino- Examples include 1-deazapurine and 6-amino-2-azapurine.

  In the present invention, the nucleoside compound is a nucleobase having a pyrimidine skeleton, a nucleobase having a purine skeleton, or a base analog having an N-glucoside bond at the 1-position of the above-mentioned polyhydroxyaldehyde or polyhydroxyketone and derivatives thereof. Specifically, thymidine, deoxycytidine, deoxyuridine, deoxyguanosine, deoxyadenosine, dideoxyadenosine, trifluorothymidine, ribavirin, orotidine, uracil arabinoside, adenine arabinoside, 2-methyl-adenine arabinoside, 2- Chlor-hypoxanthine arabinoside, thioguanine arabinoside, 2,6-diaminopurine arabinoside, cytosine arabinoside, guanine arabinoside, thymine arabinoside, enocitabine, gemcitabi , Azidothymidine, idoxuridine, dideoxyadenosine, dideoxyinosine, dideoxycytidine, didehydrodeoxythymidine, thiadideoxycytidine, soribudine, 5-methyluridine, birazole, thioinosine, tegafur, doxyfluridine, bledinin, nebulaline, allopurinol uracil, 5-fluorouracil Examples include 2'-aminouridine, 2'-aminoadenosine, 2'-aminoguanosine, 2-chloro-2'-aminoinosine.

  The nucleoside phosphorylase in the present invention is a general term for enzymes that degrade the N-glycoside bond of a nucleoside compound in the presence of phosphoric acid, and a reverse reaction can be used in the present invention. The enzyme used for the reaction may be of any kind and origin as long as it has an activity capable of producing the target nucleoside compound from the corresponding pentose-1-phosphate and nucleobase or nucleobase analog. The enzyme is roughly classified into a purine type and a pyrimidine type. Examples of known enzymes include purine nucleoside phosphorylase (EC 2.4.2.1), guanosine phosphorylase (EC 2.4.2.15) as purine type, and pyrimidine nucleoside as pyrimidine type. Examples include phosphorylase (EC2.4.2.2), uridine phosphorylase (EC2.4.2.3), thymidine phosphorylase (EC2.4.2.4), deoxyuridine phosphorylase (EC2.4.2.23), and the like.

  Microorganisms having nucleoside phosphorylase activity in the present invention include purine nucleoside phosphorylase (EC 2.4.2.1), guanosine phosphorylase (EC 2.4.2.15), pyrimidine nucleoside phosphorylase (EC 2.4.2.2), uridine phosphorylase (EC 2.4.2). .3), as long as it is a microorganism expressing one or more nucleoside phosphorylases selected from the group consisting of thymidine phosphorylase (EC2.4.2.4) and deoxyuridine phosphorylase (EC2.4.2.23) .

  Specific examples of such microorganisms include Nocardia genus, Microbacterium genus, Corynebacterium genus, Brevibacterium genus, Cellulomonas genus, Flavobacteria. Umbrella (Flabobacterium), Kluyvere, Micobacterium, Haemophilus, Micoplana, Protaminobacter, Candida, Saccharomyces ( Saccharomyces genus, Bacillus genus, thermophilic Bacillus genus, Pseudomonas genus, Micrococcus genus, Hafnia genus, Proteus genus, Vibrio genus, Staphylococcus (Staphyrococcus), Propionibacterium, Sartina, Planococcus (Plan ococcus genus, Escherichia genus, Kurthia genus, Rhodococcus genus, Acinetobacter genus, Xanthobacter genus, Streptomyces genus, Rhizobium genus Rhizobium Salmonella genus, Klebsiella genus, Enterobacter genus, Erwinia genus, Aeromonas genus, Citrobacter genus, Achromobacter genus, Achromobacter genus, Agrobacterium ( Suitable examples include microbial strains included in the genus Agrobacterium, the genus Arthrobacter, or the genus Pseudonocardia.

  Due to recent advances in molecular biology and genetic engineering, by analyzing the molecular biological properties and amino acid sequence of the nucleoside phosphorylase of the above-mentioned microbial strain, the gene of the protein is obtained from the microbial strain, and the gene It is possible to construct a recombinant plasmid into which a control region necessary for expression is inserted and introduce it into an arbitrary host to produce a genetically modified bacterium that expresses the protein, and relatively easily. It also became. In view of the state of the art, a genetically modified bacterium in which such a nucleoside phosphorylase gene is introduced into an arbitrary host is also included in the microorganism expressing the nucleoside phosphorylase of the present invention.

The control region necessary for expression herein refers to a promoter sequence (including an operator sequence that controls transcription), a ribosome binding sequence (SD sequence), a transcription termination sequence, and the like. Specific examples of the promoter sequence, and P _L promoter and P _R promoter from a lac promoter lambda phage trp promoter lactose operon tryptophan operon from Escherichia coli, Bacillus subtilis-derived gluconic acid synthetase promoter (gnt), alkali Examples include protease promoter (apr), neutral protease promoter (npr), α-amylase promoter (amy), and the like. In addition, a uniquely modified and designed sequence such as the tac promoter can also be used. Examples of the ribosome binding sequence include sequences derived from Escherichia coli or Bacillus subtilis, but are not particularly limited as long as the sequence functions in a desired host such as Escherichia coli or Bacillus subtilis. For example, a consensus sequence in which a sequence complementary to the 3 ′ end region of 16S ribosomal RNA is continuous by 4 or more bases may be prepared by DNA synthesis and used. A transcription termination sequence is not always necessary, but a ρ-factor-independent sequence such as a lipoprotein terminator, a trp operon terminator, etc. can be used. The sequence of these control regions on the recombinant plasmid is preferably arranged in the order of promoter sequence, ribosome binding sequence, gene encoding nucleoside phosphorylase, and transcription termination sequence from the 5 ′ end upstream.

  Specific examples of the plasmid herein include pBR322, pUC18, Bluescript II SK (+), pKK223-3, pSC101 having autonomously replicable regions in E. coli, and autonomous replication in Bacillus subtilis. PUB110, pTZ4, pC194, ρ11, φ1, φ105, etc. having various regions can be used as vectors. Further, as examples of plasmids capable of autonomous replication in two or more types of hosts, pHV14, TRp7, YEp7 and pBS7 can be used as vectors.

  As an arbitrary host mentioned here, Escherichia coli can be mentioned as a representative example as in Examples described later, but is not particularly limited to Escherichia coli, and Bacillus subtilis and other Bacillus species. Other microbial strains such as yeast and actinomycetes are also included.

  As the nucleoside phosphorylase or the microorganism having the enzyme activity in the present invention, commercially available enzymes, microbial cells having the enzyme activity, processed microbial cells, or immobilized products thereof can be used. Processed bacterial cells include, for example, acetone-dried bacterial cells and bacteria prepared by mechanical disruption, ultrasonic disruption, freeze-thaw treatment, pressure / pressure reduction treatment, osmotic pressure treatment, self-digestion, cell wall degradation treatment, surfactant treatment, etc. A crushed body or the like, and if necessary, those obtained by repeated purification by ammonium sulfate precipitation, acetone precipitation, or column chromatography may be used.

  In the present invention, a metal cation capable of forming a poorly water-soluble salt with phosphate ion is one that forms a poorly water-soluble salt with phosphate ion by-produced in the reaction and can precipitate in the reaction solution. There is no limitation. Examples thereof include metal cations such as sodium, potassium, calcium, magnesium, aluminum, barium, iron, cobalt, nickel, copper, silver, molybdenum, lead, zinc, and lithium. Among them, metal salts that are industrially versatile and safe and do not affect the reaction are particularly preferred. Examples of such salts include magnesium, calcium ions, barium ions, and aluminum ions. Two or more metal cations may be used in combination as long as the effects of the present invention are not impaired.

  In the present invention, the metal cation capable of forming a poorly water-soluble salt with phosphate ion is selected from the group consisting of chloride ion, nitrate ion, carbonate ion, sulfate ion, and acetic acid. It can be added to the reaction solution as a metal salt with one or more kinds of anions selected from ions or hydroxide ions. Specifically, calcium chloride, calcium nitrate, calcium carbonate, calcium sulfate, calcium acetate, barium chloride, barium nitrate, barium carbonate, barium sulfate, barium acetate, aluminum chloride, aluminum nitrate, aluminum carbonate, aluminum sulfate, aluminum acetate, Examples include sodium hydrogen carbonate, sodium carbonate, sodium hydroxide, potassium hydrogen carbonate, potassium carbonate, potassium hydroxide, lithium hydrogen carbonate, lithium carbonate, lithium hydroxide, magnesium hydroxide and the like.

  The metal cation in the present invention may be present in the reaction solution as a salt of pentose-1-phosphate. Specifically, ribose-1-phosphate / calcium salt, 2-deoxyribose-1-phosphate / calcium salt, 2,3-dideoxyribose-1-phosphate / calcium salt, arabinose-1-phosphate / Calcium salt, ribose-1-phosphate / barium salt, 2-deoxyribose-1-phosphate / barium salt, 2,3-dideoxyribose-1-phosphate / barium salt, arabinose-1-phosphate / barium salt Ribose-1-phosphate / aluminum salt, 2-deoxyribose-1-phosphate / aluminum salt, 2,3-dideoxyribose-1-phosphate / aluminum salt, arabinose-1-phosphate / aluminum salt, etc. Is mentioned.

  When a metal cation salt capable of forming a poorly water-soluble salt with phosphate ion is added to the reaction medium and added to the reaction medium, the amount of metal cation added in the aqueous solution is The amount of nucleobase or nucleobase analog is 0.5 to 20 times the molar amount, preferably 1 to 4 times the molar amount.

  When a metal cation salt is contained in an aqueous solution of a nucleobase or nucleobase analog and added to the reaction medium, the aqueous solution may be added to the reaction medium all at once before the reaction. You may make it react by adding to a reaction medium sequentially. Here, the sequential addition means dissolving or suspending a nucleobase or nucleobase analog in an aqueous solution of a salt of a metal cation and dividing it into two or more or from 1 minute to 24 hours, preferably from 30 minutes to 24 hours. It shows adding continuously to the reaction system.

  In addition, when the components necessary for the reaction are mixed together, the reaction solution may solidify depending on the amount used. In such a case, (1) pentose-1 after the reaction starts. -By adding at least one component selected from phosphoric acid, (2) nucleobase or nucleobase analog and (3) metal cation to the aqueous reaction medium in the middle of the reaction, problems such as solidification can be avoided. it can. Here, the reaction start means a state in which at least a part of the amount to be added of pentose-1-phosphate and nucleobase or nucleobase analog is added in the presence of nucleoside phosphorylase activity.

  The components added after the start of the reaction are added in one batch as described above, by the batch method or the continuous method divided into two or more times, or by the addition method consisting of a combination of the batch method and the continuous method. be able to. When there are a plurality of components to be added after the start of the reaction, it is possible to employ a method in which at least one of at least one component selected from the above three components is divided and added. That is, when a plurality of components are added after the start of the reaction, an addition method can be selected for each component.

  When an aqueous solution of a metal cation salt is mixed with a nucleobase or nucleobase analog, the amount of the metal cation salt aqueous solution used is 0.5 to 20 times that of the nucleobase or nucleobase analog. Molar amount, preferably 1 to 4 times the molar amount.

  Among metal cation salts that form a sparingly water-soluble salt with phosphoric acid, especially those that are sparingly water-soluble in water, the amount added before the end of the reaction is added to the aqueous reaction medium before starting the reaction. Since it is possible to adjust the pH of the reaction solution, it is suitable as a metal cation salt used in the present invention. Representative examples of such metal cation salts include hydroxide compounds of various metal cations, particularly magnesium hydroxide.

  The aqueous reaction medium used in the method of the present invention is a reaction medium mainly composed of water, so that the reaction utilizing the enzyme activity intended in the present invention proceeds and the effect of adding a metal cation is obtained. Anything is acceptable. Examples of such an aqueous reaction medium include water or an aqueous reaction medium obtained by adding a water-soluble organic solvent to water. Examples of the organic solvent include lower alcohols such as methanol and ethanol, acetone, dimethyl sulfoxide, and mixtures thereof. The amount of the solvent used is not particularly limited and may be used to such an extent that the reaction proceeds satisfactorily. However, the amount of the water-soluble organic solvent relative to water is preferably in the range of 0.1 to 70% by weight. . Furthermore, in order to ensure the stability of the reaction, a reaction solution using an aqueous reaction medium can be prepared as a buffer solution. As this buffer solution, a known buffer solution that can be used for the enzyme reaction according to the present invention can be used.

  The synthesis reaction of the nucleoside compound in the present invention is carried out by using the target nucleoside compound, the substrate pentose-1-phosphate and nucleobase, the reaction catalyst nucleoside phosphorylase or the microorganism having the enzyme activity, and the phosphate from the reaction system. Depending on the type of metal salt to be excluded and its characteristics, an appropriate reaction condition such as pH and temperature may be selected. Usually, the pH is 5 to 11, preferably 7.5 to 10.0, and more preferably 8.0. The temperature can be in the range of ice temperature to 80 ° C, preferably 10 to 60 ° C. Regarding the pH, if it is out of the control range, there is a possibility that the conversion of the reaction may be lowered due to the stability of the target substance or substrate, the reduction of enzyme activity, the formation of a poorly water-soluble salt with phosphoric acid, etc. . If pH changes during the reaction, an acid such as hydrochloric acid or sulfuric acid or an alkali such as sodium hydroxide or potassium hydroxide may be added as needed. Of course, it may not be necessary to adjust the pH of the reaction solution if a metal cation salt that is poorly water-soluble, particularly a metal cation hydroxide, is used.

  The concentration of pentose-1-phosphate and nucleobase used in the reaction is suitably about 0.1 to 1000 mM, and the molar ratio of both is the ratio of the nucleobase added to the pentose-1-phosphate or salt thereof. 0.1 to 10 times the molar amount. Considering the reaction conversion rate, 0.95 times the molar amount or less is preferable.

  While the reaction time varies depending on the raw materials, the type of aqueous solvent, and the reaction temperature, it is 1 minute to 78 hours, preferably 30 minutes to 24 hours.

  Moreover, the metal salt which can form a slightly water-soluble salt with the phosphoric acid to add is 0.1-10 times mole amount with respect to the pentose-1-phosphoric acid used for reaction, More preferably, it is 0.5-5. It is better to add a double molar amount. In a high concentration reaction, the nucleobase of the substrate and the nucleoside compound of the product may be present in the reaction solution without being completely dissolved, but the present invention is also applied to such a case.

  One or more selected from pentose-1-phosphate or a salt thereof, a metal cation capable of forming a poorly water-soluble salt with phosphoric acid or a salt thereof, or a nucleobase is added so that the reaction solution does not solidify. The following methods can be given as typical examples. The present invention is not limited to the following examples. If the reaction solution does not solidify, pentose-1-phosphate or a salt thereof, or a metal cation or a cation capable of forming a poorly water-soluble salt with phosphoric acid. The timing for adding one or more kinds selected from salts and nucleobases and the number of divisions are not particularly limited.

  1. Pentose-1-phosphate or a salt thereof and a nucleobase or nucleobase analog are charged all at once, the reaction is started, nucleoside compounds are accumulated to an appropriate concentration, and then a poorly water-soluble salt is formed with phosphoric acid. A method of adding all possible metal cations or salts thereof. In this case, the accumulated concentration of the nucleoside compound is preferably 10 mM or more, more preferably 30 mM or more.

  2. Pentose-1-phosphate or a salt thereof and a nucleobase or nucleobase analog are collectively added, and after starting the reaction, stepwise or continuously in accordance with the accumulated concentration of nucleoside compound, phosphoric acid and a slightly water-soluble salt A method of adding a metal cation or a salt thereof capable of forming In this case, the addition of the metal cation may be started when the nucleoside compound has accumulated preferably at least 10 mM, more preferably at least 30 mM.

  3. After adding pentose-1-phosphate or a salt thereof and a metal cation or a salt thereof capable of forming a poorly water-soluble salt with phosphoric acid at once, the nucleobase or nucleobase analog is stepped so that the reaction solution does not solidify. Or the method of adding continuously. In this case, the amount of the initial nucleobase or nucleobase analog added is preferably 30 mM or less, more preferably 10 mM or less.

  4). After adding a nucleobase or nucleobase analog and a metal cation or a salt thereof capable of forming a poorly water-soluble salt with phosphoric acid, step by step to pentose-1-phosphate or a salt thereof so that the reaction solution does not solidify. Or the method of adding continuously. In this case, the amount of initial pentose-1-phosphate or a salt thereof added is preferably 30 mM or less, more preferably 10 mM or less.

  5. A method in which pentose-1-phosphate or a salt thereof, a metal cation capable of forming a poorly water-soluble salt with phosphoric acid or a salt thereof, a nucleobase or a nucleobase analog is added stepwise or continuously to an enzyme solution. In this case, the amount of pentose-1-phosphate or a salt thereof, or nucleobase or nucleobase analog added at the start of the reaction is preferably 30 mM or less, more preferably 10 mM or less.

  In order to isolate the nucleoside compound thus produced from the reaction solution, conventional methods such as concentration, crystallization, dissolution, electrodialysis treatment, adsorption / desorption treatment with an ion exchange resin or activated carbon can be applied.

  Hereinafter, the present invention will be described with reference to examples and comparative examples, but the present invention is not limited to these examples.

(Analysis method)
All the produced nucleoside compounds were quantified by high performance liquid chromatography. Analysis conditions are as follows.
Column; YMC-Pack ODS-A312 150 × 6.0 mmI. D. (YMC Co., Ltd)
Column temperature: 40 ° C
Pump flow rate: 0.75 ml / min
Detection; UV 260 nm,
Eluent: 10 mM phosphoric acid: acetonitrile = 95: 5 (V / V)
Example 1
2.5 mM 2′-deoxyribose 1-phosphate di (monocyclohexylammonium) salt (manufactured by SIGMA), 2.5 mM adenine (manufactured by Wako Pure Chemical, special grade), 12 units / ml purine nucleoside phosphorylase (manufactured by Funakoshi) 1 ml of a reaction solution consisting of 10 mM calcium chloride (Wako Pure Chemicals, special grade), 10 mM Tris-HCl buffer (pH 7.4) was reacted at 30 ° C. for 24 hours. A white precipitate was formed after the reaction. When the reaction solution was diluted and analyzed, 2.40 mM deoxyadenosine was produced. The reaction yield at that time was 96.0%.

Comparative Example 1
The reaction was carried out under the same procedures and conditions as in Example 1 except that calcium chloride was not added. After completion of the reaction, no precipitate was formed. When the reaction solution was diluted and then analyzed, 2.01 mM deoxyadenosine was produced. The reaction yield at that time was 80.4%.

Example 2
The reaction was carried out under the same procedures and conditions as in Example 1 except that the calcium chloride concentration was 2.5 mM. A white precipitate was formed after the reaction. When the reaction solution was diluted and analyzed, 2.27 mM deoxyadenosine was produced. The reaction yield at that time was 90.8%.

Example 3
The reaction was carried out under the same procedure and conditions as in Example 1 except that aluminum chloride was added instead of calcium chloride. A white precipitate was formed after the reaction. When the reaction solution was diluted and analyzed, 2.31 mM deoxyadenosine was produced. The reaction yield at that time was 93.3%.

Example 4
The reaction was carried out under the same procedure and conditions as in Example 1 except that barium chloride was added instead of calcium chloride. A white precipitate was formed after the reaction. When the reaction solution was diluted and analyzed, 2.31 mM deoxyadenosine was produced. The reaction yield at that time was 92.4%.

Example 5
The reaction was carried out under the same procedure and conditions as in Example 4 except that the barium chloride concentration was 2.5 mM. A white precipitate was formed after the reaction. When the reaction solution was diluted and analyzed, 2.27 mM deoxyadenosine was produced. The reaction yield at that time was 90.2%.

Example 6
Journal of Biological Chemistry, Vol. 184, pp 449-459, 1950, 2-deoxyribose 1-phosphate barium salt was prepared. 2.5 mM 2-deoxyribose-1-phosphate barium salt, 2.5 mM adenine (manufactured by Wako Pure Chemical, special grade), 12 units / ml purine nucleoside phosphorylase (manufactured by Funakoshi), 10 mM calcium chloride (Wako Pure Chemical) 1 ml of a reaction solution consisting of 10 mM Tris-HCl buffer (pH 7.4) was reacted at 30 ° C. for 24 hours. A white precipitate was formed after the reaction. When the reaction solution was diluted and analyzed, 2.40 mM deoxyadenosine was produced. The reaction yield at that time was 91.1%.

Example 7
2.5 mM 2-deoxyribose-1-phosphate di (monocyclohexylammonium) salt (manufactured by SIGMA), 2.5 mM thymine (manufactured by Wako Pure Chemical, special grade), 12 units / ml thymidine phosphorylase (manufactured by SIGMA), 1 ml of a reaction solution consisting of 10 mM calcium nitrate (Wako Pure Chemicals, special grade) and 10 mM Tris-HCl buffer (pH 7.4) was reacted at 30 ° C. for 24 hours. A white precipitate was formed after the reaction. When the reaction solution was diluted and analyzed, 2.28 mM thymidine was produced. The reaction yield at that time was 91.2%.

Comparative Example 2
The reaction was carried out under the same procedures and conditions as in Example 7 except that calcium nitrate was not added. After completion of the reaction, no precipitate was formed. When the reaction solution was diluted and then analyzed, 1.88 mM thymidine was produced. The reaction yield at that time was 75.2%.

Example 8
2.5 mM ribose-1-phosphate cyclohexylammonium salt (SIGMA), 2.5 mM 2,6-diaminopurine (Aldrich), 12 units / ml purine nucleoside phosphorylase (Funakoshi), 10 mM calcium chloride ( 1 ml of a reaction solution consisting of 10 mM Tris-HCl buffer (pH 7.4) was reacted at 30 ° C. for 24 hours. A white precipitate was formed after the reaction. When the reaction solution was diluted and then analyzed, 1.94 mM 2,6-diaminopurine riboside was produced. The reaction yield at that time was 77.6%.

Comparative Example 3
The reaction was carried out under the same procedures and conditions as in Example 8 except that calcium chloride was not added. After completion of the reaction, no precipitate was formed. When the reaction solution was diluted and then analyzed, 1.54 mM 2,6-diaminopurine riboside was produced. The reaction yield at that time was 61.6%.

Example 9
E. coli chromosomal DNA was prepared as follows. Escherichia coli K-12 / XL-10 strain (Stratagene) was inoculated into 50 ml of LB medium, cultured at 37 ° C. overnight, collected, and lysed with a lysate containing 1 mg / ml of lysozyme. After the lysate was treated with phenol, DNA was precipitated by ethanol precipitation by an ordinary method. The resulting DNA precipitate was collected by winding it around a glass rod, washed, and used for PCR.

The primer for PCR has the nucleotide sequences shown in SEQ ID NOs: 1 and 2 designed based on the known deoD gene nucleotide sequence of Escherichia coli (GenBank accession No. AE000508 (coding region is nucleotide numbers 11531-12250)) Oligonucleotides (synthesized outsourced to Hokkaido System Science Co., Ltd.) were used.
SEQ ID NO: 1:
gtgaattcac aaaaaggata aaacaatggc
SEQ ID NO: 2:
tcgaagcttg cgaaacacaa ttactcttt
These primers have EcoRI and HindIII restriction enzyme recognition sequences near the 5 ′ and 3 ′ ends, respectively.

  Using 0.1 ml of PCR reaction solution containing 6 ng / μl of the above-mentioned Escherichia coli chromosomal DNA completely digested with restriction enzyme HindIII and 3 μM of each primer, denaturation: 96 ° C., 1 minute, annealing: 55 ° C., 1 minute, extension reaction : PCR was carried out under the condition of 30 cycles of 74 ° C. for 1 minute.

  The reaction product and plasmid pUC18 (Takara Shuzo Co., Ltd.) were digested with EcoRI and HindIII and ligated using Ligation High (Toyobo Co., Ltd.), and then the resulting recombinant plasmid was used to produce Escherichia coli. DH5α was transformed. The transformed strain was cultured on an LB agar medium containing 50 μg / ml of ampicillin (Am) and X-Gal (5-bromo-4-chloro-3-indolyl-β-D-galactoside), and was Am-resistant and white colony. A transformed strain was obtained.

  A plasmid was extracted from the transformant thus obtained, and the plasmid into which the target DNA fragment was inserted was named pUC-PNP73. The transformant thus obtained was named Escherichia coli MT-10905.

  Escherichia coli MT-10905 strain was cultured with shaking at 37 ° C. overnight in 100 mL of LB medium containing 50 μg / ml of Am. The obtained culture broth was centrifuged at 13000 rpm for 10 min to collect bacterial cells. The cells were suspended in 10 mL of 10 mM Tris-HCl buffer (pH 8.0) and crushed by ultrasonic waves, and used as the enzyme source.

  100 mM 2′-deoxyribose 1-phosphate di (monocyclohexylammonium) salt (manufactured by SIGMA), 10-80 mM adenine (manufactured by Wako Pure Chemicals, special grade), 100 mM Tris-HCl buffer (pH 8.0), 20 units A reaction solution of 1.0 ml / ml of the above purine nucleoside phosphorylase was reacted at 50 ° C. for 20 hours. Calcium chloride was added so that the concentration became 150 mM 8 hours after the start of the reaction. The results are shown in Table 1.

Comparative Example 4
Simultaneously with the addition of the enzyme source, calcium chloride was added, and the reaction was carried out in the same manner as in Example 9. The results are shown in Table 2.

Comparative Example 5
The reaction of 80 mM adenine was carried out in the same manner as in Example 9 without adding a buffer solution. The results are shown in Table 3.

Example 10
100 mM 2′-deoxyribose 1-phosphate di (monocyclohexylammonium) salt (manufactured by SIGMA), 10-80 mM thymine (manufactured by Wako Pure Chemicals, special grade), 100 mM Tris-HCl buffer (pH 8.0), 20 units 1.0 ml of a reaction solution composed of / ml thymidine phosphorylase (manufactured by SIGMA) was reacted at 50 ° C. for 20 hours. Calcium chloride was added so that the concentration became 150 mM 8 hours after the start of the reaction. The results are shown in Table 4.

Comparative Example 6
Simultaneously with the addition of the enzyme source, calcium chloride was added, and the reaction was carried out in the same manner as in Example 10. The results are shown in Table 5.

Comparative Example 7
The reaction of 80 mM thymine was carried out in the same manner as in Example 10 without adding a buffer solution. The results are shown in Table 6.

Example 11
0.5 ml of a reaction solution consisting of 200 mM thymine (manufactured by Wako Pure Chemicals, special grade), 200 mM Tris-HCl buffer (pH 8.0), 20 units / ml thymidine phosphorylase (manufactured by SIGMA) was kept at 50 ° C., and 2 ′ -A 200 mM solution of deoxyribose 1-phosphate di (monocyclohexylammonium) salt (manufactured by SIGMA) was added in five portions of 0.1 mL every hour after the addition of the enzyme solution. As a result, the reaction solution remained liquid.

Comparative Example 8
Simultaneously with the addition of the enzyme source in the absence of Tris-HCl buffer, 0.5 mL of 200 mM 2′-deoxyribose 1-phosphate di (monocyclohexylammonium) salt (manufactured by SIGMA) was added and reacted in the same manner as in Example 11. Went. As a result, the reaction solution solidified.

Example 12
200 mM 2′-deoxyribose 1-phosphate di (monocyclohexylammonium) salt (manufactured by SIGMA), 200 mM tris-HCl buffer (pH 8.0), 20 units / ml thymidine phosphorylase (manufactured by SIGMA), 150 mM calcium chloride The reaction solution (0.5 ml) was kept at 50 ° C., and a 200 mM thymine (made by Wako Pure Chemicals, special grade) solution was added in 0.1 mL portions every 5 hours. As a result, the reaction solution remained liquid.

Comparative Example 9
The reaction was carried out in the same manner as in Example 12 except that 0.5 mL of 200 mM thymine solution was added simultaneously with the addition of the enzyme source without the presence of Tris-HCl buffer. As a result, the reaction solution solidified.

All nucleoside compounds produced in the following examples and the like were quantified by high performance liquid chromatography under the following analytical conditions.
Column: YMC-Pack ODS-A514 300 × 6.0 mmI. D. (YMC Co., Ltd)
Column temperature: 40 ° C
Pump flow rate: 1 ml / min
Detection wavelength: UV254 nm
Eluent: Add phosphoric acid to 20 mmol aqueous ammonium acetate solution (2700 ml) to adjust to pH 3.5, add methanol (300 ml), mix and degas.
Internal standard substance: Nicotinic acid Reference Example 1
Synthesis of 2-deoxyribose 1-phosphate di (ammonium) salt 2-deoxyribose 1-phosphate di (monocyclohexylammonium) salt (1 g, 2.42 mmol, manufactured by SIGMA) was suspended in methanol (10 g) and ammonia. Gas (0.62 g, 36.5 mmol) is blown and stirred at 50 ° C. for 2 hours. The resulting reaction mass was filtered at 30 ° C., washed twice with methanol (5 g) and dried to obtain the desired 2′-deoxyribose 1-phosphate di (ammonium) salt (0.57 g) in a yield of 95%. Got in.
¹ H-NMR (D ₂ O, 270 MHz) d 5.56 (s, 1 H), 4.03 (m, 2 H), 3.52 (dd, J = 3.3, 12.2 Hz, 1 H), 3.41 (dd, J = 5.3, 12.2 Hz, 1 H), 2.17 (m, 1 H), 1.87 (d, J = 13.9 Hz, 1 H), MS (APCI) m / z 213 (MH)
Example 13
Synthesis of 2'-deoxyguanosine (1)
2-Deoxyribose 1-phosphate di (monocyclohexylammonium) salt (3.22 g, 7.72 mmol, manufactured by SIGMA) was dissolved in water (47.1 g), and the enzyme solution obtained in Example 9 (0.1 ml) ) Was added dropwise to a reaction solution in which 4.02 wt% sodium hydroxide aqueous solution (16.45 g, 16.5 mmol) was dissolved in guanine (1 g, 6.62 mmol) at 50 ° C. over 1 hour. . The reaction mass was reacted at the same temperature for 2 hours, and then the reaction mass was analyzed by HPLC. As a result, the desired 2′-deoxyguanosine was obtained in a reaction yield of 80%.

Example 14
Synthesis of 2'-deoxyguanosine (2)
2-Deoxyribose 1-phosphate di (ammonium) salt (2.0 g, 7.72 mmol) synthesized in Reference Example 1 was dissolved in water (47.1 g), and the enzyme solution (0. 1 ml) was added dropwise to a reaction solution obtained by dissolving guanine (1 g, 6.62 mmol) in 4.02 wt% sodium hydroxide aqueous solution (16.45 g, 16.5 mmol) at 50 ° C. over 1 hour. did. The reaction mass was reacted at the same temperature for 2 hours, and then the reaction mass was analyzed by HPLC. As a result, the desired 2′-deoxyguanosine was obtained in a reaction yield of 81%.

Example 15
Synthesis of 2'-deoxyguanosine (3)
2-Deoxyribose 1-phosphate di (ammonium) salt (2.0 g, 7.72 mmol) synthesized in Reference Example 1 was dissolved in water (47.1 g), and the enzyme solution (0. 1 ml) was added dropwise to a solution obtained by dissolving guanine (1 g, 6.62 mmol) in a 5.6 wt% aqueous potassium hydroxide solution (16.5 g, 16.5 mmol) at 50 ° C. over 1 hour. did. The reaction mass was reacted at the same temperature for 2 hours, and then the reaction mass was analyzed by HPLC. As a result, the desired 2′-deoxyguanosine was obtained in a reaction yield of 79%.

Example 16
Synthesis of 2'-deoxyguanosine (4)
2-Deoxyribose 1-phosphate di (ammonium) salt (2.0 g, 7.72 mmol) synthesized in Reference Example 1 was dissolved in water (47.1 g), and the enzyme solution (0. 1 ml) was added dropwise to a reaction solution obtained by dissolving guanine (1 g, 6.62 mmol) in a 2.4 wt% lithium hydroxide aqueous solution (16.5 g, 16.5 mmol) at 50 ° C. over 1 hour. did. The reaction mass was reacted at the same temperature for 2 hours, and then the reaction mass was analyzed by HPLC. As a result, the desired 2′-deoxyguanosine was obtained in a reaction yield of 96%.

Example 17
Synthesis of 2′-deoxyadenosine 2-Deoxyribose 1-phosphate di (ammonium) salt (2.0 g, 7.72 mmol) synthesized in Reference Example 1 was dissolved in water (30 g) and obtained in Example 9. A solution obtained by dissolving adenine (0.89 g, 6.62 mmol) in a 2.4 wt% lithium hydroxide aqueous solution (16.5 g, 16.5 mmol) in a reaction solution to which an enzyme solution (0.05 ml) was added, It was dripped at 1 degreeC over 1 hour. The reaction mass was reacted at the same temperature for 2 hours, and then the reaction mass was analyzed by HPLC. As a result, the desired 2′-deoxyadenosine was obtained in a reaction yield of 98%.

Example 18
Synthesis of 2'-deoxyadenosine To pure water (13 g), 2-deoxyribose 1-phosphate diammonium salt (1.67 g, 6.7 mmol), adenine (0.87 g, 6.4 mmol) and magnesium hydroxide (0 .59 g, 10.1 mmol) was added. 0.05 ml of the enzyme solution was added to the mass, and the reaction was carried out with stirring at 45 ° C. for 3 hours. The reaction yield at that time was 98%. The obtained reaction mass was heated to 70 ° C. to dissolve 2′-deoxyadenosine, and then insoluble magnesium phosphate produced by the reaction was filtered using 5A filter paper, washed with water (5 g), and a clear filtrate. (18.2 g) was obtained from the reaction mass in 99% yield. The filtration rate was 1000 kg / m 3 / hr, and the loss rate of 2′-deoxyadenosine to the filter cake was 1%. The filtrate thus obtained was crystallized at 5 ° C. for 2 hours, and the precipitated crystals were filtered, washed with water (5 g) and dried under reduced pressure to obtain the desired 2′-deoxyadenosine (1.6 g). Obtained at a rate of 93%.

Comparative Example 10
Synthesis of 2'-deoxyadenosine 2-deoxyribose 1-phosphate diammonium salt (1.67 g, 6.7 mmol), adenine (0.87 g, 6.4 mmol) and 0.05 ml of enzyme in pure water (13 g) An aqueous solution (3.7 g) in which calcium chloride monohydrate (1.48 g) is dissolved at 45 ° C. and a 4% aqueous sodium hydroxide solution (20.1 g) are simultaneously added dropwise to the suspended liquid over 2 hours. To do. After completion of the dropping, the reaction mass was reacted at the same temperature for 3 hours. The reaction yield at that time was 97%. The obtained reaction mass was heated to 70 ° C. to dissolve 2′-deoxyadenosine, and then the insoluble calcium phosphate produced by the reaction was filtered using 5A filter paper, washed with water (5 g), and a clear filtrate (28 .2 g) was obtained from the reaction mass in 85% yield. The filtration rate was 50 kg / m 3 / hr, and the loss rate of 2′-deoxyadenosine to the filter cake was 15%. The filtrate thus obtained was crystallized at 5 ° C. for 2 hours, and the precipitated crystals were filtered, washed with water (5 g) and dried under reduced pressure to collect the desired 2′-deoxyadenosine (1.3 g). Obtained at a rate of 75%.

Example 19
Synthesis of 2'-deoxyadenosine To pure water (13 g), 2-deoxyribose 1-phosphate diammonium salt (1.67 g, 6.7 mmol), adenine (0.87 g, 6.4 mmol) and magnesium hydroxide (0 .59 g, 10.1 mmol) was added. To the mass, the enzyme solution (0.05 ml) obtained in Example 9 was added and allowed to react at 45 ° C. with stirring for 3 hours. When the reaction mass was analyzed by HPLC after 3 hours, the desired 2'-deoxyadenosine was obtained in a reaction yield of 98%. The pH during the reaction was 8-10.

Example 20
Synthesis of 2'-deoxyguanosine 2-deoxyribose 1-phosphate diammonium salt (1.67 g, 6.7 mmol), guanine (0.92 g, 6.1 mmol) and magnesium hydroxide (0) in pure water (15 g) .59 g, 10.1 mmol) was added. To the mass, the enzyme solution (0.2 ml) obtained in Example 9 was added and allowed to react at 50 ° C. with stirring for 6 hours. When the reaction mass was analyzed by HPLC after 6 hours, the desired 2′-deoxyguanosine was obtained in a reaction yield of 98%. The pH during the reaction was 8-10.
Example 21
Synthesis of 2'-deoxyadenosine Pure water (13 g) was mixed with 2-deoxyribose 1-phosphate diammonium salt (1.67 g, 6.7 mmol), adenine (0.87 g, 6.4 mmol) and magnesium hydroxide (0 .59 g, 10.1 mmol) was added. The enzyme solution (0.05 ml) obtained in Example 9 was added to the mass, and the mixture was reacted with stirring at 45 ° C. for 3 hours while adjusting the pH to 8.5 with acetic acid. When the reaction mass was analyzed by HPLC after 3 hours, the desired 2'-deoxyadenosine was obtained in a reaction yield of 98%.

Comparative Example 11
Synthesis of 2'-deoxyadenosine 2-deoxyribose 1-phosphate diammonium salt (1.67 g, 6.7 mmol), adenine (0.87 g, 6.4 mmol) and magnesium chloride hexahydrate in pure water (13 g) (2.05 g, 10.1 mmol) was added. To the mass, the enzyme solution (0.05 ml) obtained in Example 9 was added and allowed to react at 45 ° C. with stirring for 3 hours. When the reaction mass was analyzed by HPLC after 3 hours, the desired 2'-deoxyadenosine was obtained in a reaction yield of 65%. The pH during the reaction was 6 to 7.5.

Comparative Example 12
Synthesis of 2'-deoxyguanosine 2-deoxyribose 1-phosphate diammonium salt (1.67 g, 6.7 mmol), guanine (0.92 g, 6.1 mmol) and magnesium chloride hexahydrate in pure water (15 g) (2.05 g, 10.1 mmol) was added. To the mass, the enzyme solution (0.2 ml) obtained in Example 9 was added and reacted at 50 ° C. with stirring for 3 hours. When the reaction mass was analyzed by HPLC after 3 hours, the desired 2'-deoxyguanosine was obtained in a reaction yield of 65%. The pH during the reaction was 6 to 7.5.

Comparative Example 13
Synthesis of 2'-deoxyadenosine Similarly to Example 21, the yield when the reaction was carried out while adjusting the reaction pH using acetic acid or ammonia and NaOH is shown in Table 7 below. From the results, it can be seen that the yield decreases even when the pH is less than 7.5 or 10.5 or more.

Comparative Example 14
Synthesis of 2'-deoxyadenosine In the reaction method of Example 19 and Comparative Example 11, the reaction yield was changed when the amount of pure water added was changed while adjusting the reaction pH to 9.0 using ammonia. It is shown in Table 8 below. From this table, it can be seen that the yield of the chloride salt cannot be improved unless the reaction concentration is lowered due to the influence of the produced ammonium chloride.

Claims (4)

  In an aqueous reaction medium, in the presence of nucleoside phosphorylase activity, pentose-1-phosphate and a nucleobase or nucleobase analog, in the presence of a metal cation salt that forms a sparingly water-soluble salt with a phosphate ion. A method for producing a nucleoside compound that is reacted without adjusting pH to produce a nucleoside compound, wherein the metal cation salt is a poorly water-soluble salt in water.   The method for producing a nucleoside compound according to claim 1, wherein the metal cation salt is at least one selected from magnesium hydroxide, magnesium oxide, magnesium carbonate, and basic magnesium carbonate.   The method for producing a nucleoside compound according to claim 2, wherein the pH of the aqueous reaction medium during the reaction is in the range of 7.5 to 10.0.   The method for producing a nucleoside compound according to claim 2, further comprising a step of filtering the reaction solution obtained by the reaction to remove insoluble substances in the reaction solution to obtain a filtrate containing the nucleoside compound. .