JP6311998B2 - Method for producing α-amino nitrile compound - Google Patents

Description

  The present invention relates to a method for producing an α-amino nitrile compound using amino acid oxidase.

  The α-amino nitrile compound is useful not only as an α-amino acid but also as a synthetic intermediate for nitrogen-containing heterocyclic compounds such as thiadiazoles and imidazoles. As one of the typical production methods, the Stricker reaction is known.

  The Strecker reaction is generally a method for producing an α-amino acid by acid-hydrolyzing a cyano group after reacting an aldehyde compound or a ketone compound with an ammonium ion and a cyanide ion to form an α-amino nitrile compound. .

  As an organic chemical Strecker reaction, for example, an aldehyde compound, an amine compound, and hydrogen cyanide are reacted in the presence of a chiral zirconium catalyst obtained by mixing a zirconium alkoxide and an optically active binaphthol compound. A method for producing an active α-amino nitrile compound is known (Patent Document 1). As a method using an enzyme, a mutant enzyme in which the 336th asparagine of monoamine oxidase derived from S stereoselective Aspergillus niger is converted to serine is used, and potassium cyanide is added to the product when pyrrolidine is used as a substrate. It is known to synthesize an amino nitrile compound (Non-patent Document 1).

  In addition, as a Strecker reaction using an enzyme, for example, a mutant enzyme in which N-336 of S-stereoselective monoamine oxidase derived from Aspergillus niger is converted to serine is used, and potassium cyanide is added to the product when pyrrolidine is used as a substrate. Thus, a method of synthesizing an aminonitrile compound is known (Non-Patent Document 1).

Japanese Patent No. 3634207

Angew. Chem. Int. Ed. 49: 2182-2184 (2010)

  As described above, there is a report that an aminonitrile compound was produced using monoamine oxidase.

  However, in a conventional experimental example of an aminonitrile compound using amine oxidase, only a cyclic amine compound is used as a substrate, and no other compound is used.

  Therefore, an object of the present invention is to provide a method for efficiently producing an α-amino nitrile compound from an acyclic amine compound.

  The inventors of the present invention have made extensive studies to solve the above problems. As a result, the inventors have found that an α-amino nitrile compound can be efficiently produced from a specific amine compound by using natural or mutant amino acid oxidase instead of amine oxidase, thereby completing the present invention.

  The present invention is shown below.

[1] A method for producing an α-amino nitrile compound comprising:
The process which makes the imine compound represented by following formula (II) by making amino acid oxidase act on the amine compound represented by following formula (I):

[Wherein, R ¹ represents a C _6-12 aryl group which may have a substituent, a heteroaryl group which may have a substituent, or a carboxy group, and R ² represents C _1-6 An alkyl group, a C _6-12 aryl-C _1-6 alkyl group optionally having a substituent on a C _6-12 aryl group, or a hetero ring optionally having a substituent on a heteroaryl group An aryl-C _1-6 alkyl group, and the substituent that the C _6-12 aryl group and heteroaryl group may have is a halogen atom]; and a cyanide ion acting on the imine compound (II). And a step of obtaining an α-alkylamino nitrile compound represented by the following formula (III).

[Wherein R ¹ and R ² have the same meaning as above]
In the present invention, the “C _6-12 aryl group” refers to an aromatic hydrocarbon group having 6 to 12 carbon atoms. Examples thereof include a phenyl group, an indenyl group, a naphthyl group, and a diphenyl group. Of these, a phenyl group is preferred.

  “Heteroaryl group” means a 5-membered aromatic heterocyclyl group, 6-membered aromatic heterocyclyl group or condensed ring aromatic heterocyclyl group having at least one heteroatom such as a nitrogen atom, oxygen atom or sulfur atom. “Heteroaryl group” includes pyrrolyl group, imidazolyl group, pyrazolyl group, thienyl group, furyl group, oxazolyl group, isoxazolyl group, thiazolyl group, isothiazolyl group, thiadiazole group and the like; pyridinyl group, pyrazinyl group A 6-membered heteroaryl group such as a group, a pyrimidinyl group, a pyridazinyl group; and a condensed ring heteroaryl group such as a benzofuranyl group, an indolyl group, a chromenyl group, a quinolinyl group, and an isoquinolinyl group.

The “C _1-6 alkyl group” refers to a linear or branched monovalent aliphatic saturated hydrocarbon group having 1 to 6 carbon atoms. For example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-pentyl group, n-hexyl group and the like can be mentioned. Of these, a C _1-4 alkyl group is preferable, a C _1-2 alkyl group is more preferable, and a methyl group is particularly preferable.

“C _6-12 aryl-C _1-6 alkyl group” refers to the above C _1-6 alkyl group substituted with one of the above C _6-12 aryl groups, and “heteroaryl-C _1-6 alkyl group” _{Means the} C _1-6 alkyl group substituted by one heteroaryl group.

  The “halogen atom” includes a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, more preferably a fluorine atom or a chlorine atom, and most preferably a fluorine atom.

When the C _6-12 aryl group or heteroaryl group has a substituent, the number of substituents is not particularly limited, but can be, for example, 1 or more and 5 or less, preferably 1 or more and 3 or less, One or two is more preferable. When the number of substituents is 2 or more, the substituents may be the same as or different from each other.

  [2] The method according to [1] above, wherein the mutant amino acid oxidase of any one of (1) to (3) below is used as the amino acid oxidase.

(1) A mutant amino acid oxidase having an amino acid sequence in which the 228th amino acid is substituted with tyrosine or leucine and the 283rd arginine is substituted with glycine, alanine or cysteine in the amino acid sequence shown in SEQ ID NO: 1;
(2) A mutation having an amino acid sequence in which one or several amino acids are deleted, substituted and / or added in the region excluding the 228th and 283rd amino acids in the amino acid sequence defined in (1) above A variant amino acid oxidase which is an amino acid oxidase and has an oxidation activity for (R) -amine compounds; or (3) an amino acid having 95% or more sequence identity to the amino acid sequence defined in (1) above Mutant amino acid oxidase having a sequence and oxidative activity against (R) -amine compound (however, in the amino acid sequence of the mutant amino acid oxidase, the amino acids corresponding to the 228th and 283rd amino acid sequences are not mutated) And).

  [3] The method according to [2] above, wherein in the mutant amino acid oxidase (1), the 228th amino acid is leucine and the 283rd arginine is glycine.

[4] R ¹ represents an optionally substituted C _6-12 aryl group or an optionally substituted heteroaryl group, and R ² represents a C _1-6 alkyl group. [2] or [3].

  [5] The method according to any one of [2] to [4] above, wherein R form is used as the amine compound (I).

  [6] The method according to [1] above, wherein L-amino acid oxidase derived from Crotalus atox is used as the amino acid oxidase.

  [7] The method according to [1] above, wherein the L-amino acid oxidase according to any one of (4) to (6) below is used as the amino acid oxidase.

(4) L-amino acid oxidase having the amino acid sequence of SEQ ID NO: 42;
(5) A mutant amino acid oxidase having an amino acid sequence in which one or several amino acids are deleted, substituted and / or added in the amino acid sequence defined in (4) above, and has an oxidative activity against L-amino acids Or (6) a mutant having an amino acid sequence having a sequence identity of 95% or more with respect to the amino acid sequence defined in (4) above and having an oxidative activity for L-amino acid oxidase Amino acid oxidase.

  If a natural or mutant amino acid oxidase is used, an α-amino nitrile compound can be efficiently produced from a specific amine compound.

It is a graph which shows the result of having tested the substrate specificity with respect to (R)-(alpha) -methylbenzylamine of the mutant type enzyme which introduce | transduced the mutation into the specific position of the wild type amino acid oxidase. It is a photograph of SDS-PAGE of the purified purified mutant (R) -amino acid oxidase according to the present invention. It is a graph which shows the relationship between the specific activity of the said mutant | variant amino acid oxidase, and temperature. It is a graph which shows the result of having tested the heat stability of the said mutant | variant amino acid oxidase. It is the result of having tested the time-dependent change at the time of making the said mutant amino acid oxidase act on (RS)-(alpha) -methylbenzylamine. ● indicates the concentration of (R) -α-methylbenzylamine, and ○ indicates the concentration of (S) -α-methylbenzylamine. It is the result of having tested the time-dependent change at the time of making the said mutant amino acid oxidase and a reducing agent act on (RS)-(alpha) -methylbenzylamine. ● indicates the concentration of (R) -α-methylbenzylamine, and ○ indicates the concentration of (S) -α-methylbenzylamine. The HPLC chromatogram which shows (RS) -2-amino-2-methylphenyl propane nitrile production from (R)-(alpha) -methylbenzylamine using the said mutant | variant amino acid oxidase is shown. (A) is data of a standard product of (R) -methylbenzylamine, (B) is data when mutant amino acid oxidase is allowed to act on (R) -methylbenzylamine, and (C) is (R) -methyl. Data when a mutant amino acid oxidase is added to a reaction solution containing benzylamine and KCN, (D) shows data of (RS) -2-amino-2-methylphenylpropanenitrile (standard product). 8A is an HPLC chart of a solution containing D-phenylalanine and KPB, and FIG. 8B is an HPLC chart of a solution containing D-phenylalanine, KPB and porcine kidney-derived D-amino acid oxidase. (C) is an HPLC chart of the reaction solution after the above reaction. It is the result of having analyzed the peak for 10 minutes in the HPLC chart of FIG. 8 with the mass spectrum. It is a HPLC chart of the reaction solution containing L-phenylalanine, potassium phosphate buffer, potassium cyanide, and L-amino acid oxidase derived from Crotalus atox. It is the result of having analyzed the peak for 10 minutes in the HPLC chart of FIG. 10 by the mass spectrum. It is a graph which shows the time-dependent change of the density | concentration of the compound contained in the reaction liquid which manufactured 2-amino-2-propane nitrile from (R)-(alpha) -methylbenzylamine by the method of this invention. In FIG. 10, ● represents the concentration of (R) -α-methylbenzylamine, ○ represents the concentration of 2-amino-2-propanenitrile, and ▲ represents the concentration of acetophenone as a by-product.

  Hereinafter, according to the order of execution, the manufacturing method of the (alpha) -alkylamino nitrile compound which concerns on this invention is demonstrated.

(A) Production of raw material compound The amine compound (I), which is a raw material compound of the method of the present invention, may be an optical isomer or a mixture of optical isomers such as a racemate. Preferably, a material that can be easily used as a substrate for an amino acid oxidase used in the subsequent step is used. For example, when the above mutant amino acid oxidase is used, it is preferable to use the following R form. Moreover, when using L-amino acid oxidase, it is preferable to use L-amino acid, and when using D-amino acid oxidase, it is preferable to use D-amino acid.

The amine compound (I) can be purchased and used as long as it is commercially available, or may be produced by a method known to those skilled in the art because it has a relatively simple structure.

  The optical isomer of amine compound (I) can also be produced from its racemate and the like using amino acid oxidase. Hereinafter, an amine compound (IS) which is an S form of the amine compound (I) is prepared by using an enzyme capable of catalyzing a reaction of iminization using the amine compound (IR) which is an R form of the amine compound (I) as a substrate. ) Will be described using a representative example of a method for producing a racemate.

-Enzyme reaction step First, an amino acid oxidase using R form as a substrate is allowed to act on an amine compound racemic form (racemic-I), whereby an (R) -amine compound contained in the amine compound racemic form (racemic-I) ( IR) is defined as imine compound (II). As a result, substantially only the (S) -amine compound (IS) remains in the reaction solution, and deracemization is achieved.

As a solvent for the reaction solution, water is mainly used. The water is not particularly limited as long as it does not inhibit the enzyme reaction, such as ultrapure water, pure water, purified water, distilled water, ion exchange water, tap water, and well water. When the substrate compound (R) -amine compound is difficult to dissolve in water, an alcoholic solvent such as methanol or ethanol; an etheric solvent such as tetrahydrofuran; An appropriate amount of a water-miscible organic solvent such as an amide solvent such as dimethylformamide or dimethylacetamide may be added.

What is necessary is just to adjust the density | concentration in the reaction liquid of an amino acid oxidase and an amine compound racemic body suitably, and should just determine it by a preliminary experiment etc. For example, the concentration of the mutant amino acid oxidase according to the present invention can be about 0.1 U / mL or more and 30 U / mL or less. The concentration of the amine compound racemate can be 1 mM or more and 50 mM or less. In the present invention, 1U represents 1 μmol of H ₂ O when (R) -phenylalanine ((D) -phenylalanine) or (R) -α-methylbenzylamine is used as a substrate and reacted at 30 ° C. for 1 minute. _It means the amount of enzyme that produces ₂ .

  The pH of the reaction solution may be adjusted as appropriate, but is preferably adjusted to about 7.0 or more and 9.0 or less. In order to maintain the pH of the reaction solution in the above range, a buffering agent or a buffer solution may be used.

  What is necessary is just to adjust reaction temperature and reaction time suitably. As reaction temperature, it can be set as about 20 degreeC or more and 60 degrees C or less, for example. The reaction time is until the concentration of the (R) -amine compound is sufficiently reduced. Specifically, the reaction time may be determined by a preliminary experiment or the like. For example, the reaction time is about 30 minutes or more and 600 minutes or less. 60 minutes or more is preferable.

  By this step, (R) -amine compound (IR) contained in the amine compound racemic body (racemic-I) is oxidized by amino acid oxidase to become imine compound (II). Therefore, the imine compound (II) and the (S) -amine compound (IS) are separated by, for example, column chromatography to obtain the (S) -amine compound (IR) having high optical purity. it can.

[Wherein R ¹ and R ² have the same meaning as above]
-Reduction reaction process In the deracemization method of the amine compound (racemic-I) according to the present invention, the imine compound (II) may be converted into an amine compound racemate (racemic-I) by further acting a reducing agent. By this step, the (R) -amine compound (IR) becomes an amine compound racemic body (racemic-I) via the imine compound (II), and (R) in the amine compound racemic body (racemic-I). -Amine compound (IR) becomes imine compound (II) again by amino acid oxidase. That is, when the enzyme reaction step and the reduction reaction step proceed simultaneously or alternately, the (S) -amine compound (IS) contained in the raw material amine compound racemic body (racemic-I) is maintained as it is. In addition, (R) -amine compound (IR) is also converted to (S) -amine compound (IS), and (S) -amine compound (IS) having high optical purity. ) Will be manufactured efficiently.

As the reducing agent, for example, sodium borohydride, lithium borohydride, diisobutylaluminum hydride, lithium aluminum hydride, sodium cyanotrihydroborate, and borane can be used.

  Although the usage-amount of a reducing agent may be adjusted suitably, it is preferable to use the quantity which can fully reduce imine compound (II). For example, it is preferable to use about 1.5 times mol or more and 100 times mol or less with respect to the amine compound racemic body (racemic-I) which is a raw material.

  The reduction reaction step is performed after the enzyme reaction step is performed and in the presence of the (S) -amine compound (IS) or after the (S) -amine compound (IS) is separated. Alternatively, the reduction reaction step and the enzyme reaction step may be performed simultaneously. That is, a reducing agent may be added to the reaction solution of the enzyme reaction step, and the produced imine compound (II) may be immediately reduced to an amine compound racemic body (racemic-I) to be subjected to the enzyme reaction.

  In the above, using an enzyme capable of catalyzing the reaction of iminization using amine compound (I-R), which is R-form of amine compound (I), as a substrate, amine compound (I--) which is S-form of amine compound (I) A method for producing S) from a racemate was described as a representative example, but an enzyme capable of catalyzing a reaction of iminization using amine compound (IS), which is S form of amine compound (I), as a substrate, Similarly, the amine compound (IR) which is the R form of the amine compound (I) can also be produced from the racemate.

(B) Imination Step In the method of the present invention, an amino acid oxidase is allowed to act on amine compound (I) to give imine compound (II).

The amino acid oxidase used in the method of the present invention can be appropriately selected according to the amine compound (I) as a substrate. For example, when the amine compound (I) is an amino acid, a general amino acid oxidase may be used. For example, L-amino acid oxidase may be used when amine compound (I) is an L-amino acid, and D-amino acid oxidase may be used when amine compound (I) is a D-amino acid. Further, when the amine compound (I) is not an amino acid, for example, in the amine compound (I), R ¹ may have a C _6-12 aryl group which may have a substituent or a hetero which may have a substituent. When it is an aryl group and R ² is a C _1-6 alkyl group, it is preferable to use the mutant amino acid oxidase.

The mutant amino acid oxidase (1) is obtained by substituting the 283rd arginine with glycine, alanine or cysteine in the amino acid sequence (SEQ ID NO: 1) of wild-type (R) -amino acid oxidase isolated from pig kidney, The 228th tyrosine is either left as it is or substituted with leucine.

  As confirmed in the Examples, the mutant amino acid oxidase (1) does not use (R) -amino acid (D-amino acid), which is a substrate of wild-type amino acid oxidase, as a specific (R) -amine. The compound can be used as a substrate with high specificity, can be selectively converted into an imine compound having high optical purity, and has high thermal stability.

  In the present invention, an enzyme having “(specific) amino acid sequence” means that the amino acid sequence of the enzyme only needs to contain the specified amino acid sequence, and the function of the enzyme is maintained. To do. Examples of sequences other than the amino acid sequence specified in the enzyme include a histidine tag and a linker sequence for immobilization, as well as a cross-linked structure such as a -SS-bond.

  In the mutant amino acid oxidase (2), the “region excluding the 228th and 283rd amino acids” refers to the 1st to 227th and 229th to 282nd positions in the amino acid sequence of the mutant amino acid oxidase (1). And the 284th and subsequent areas.

  In addition, the range of “1 to several” in the “amino acid sequence in which one or several amino acids are deleted, substituted and / or added” indicates that an amino acid oxidase having a deletion or the like is oxidized to (R) -amine compound. It does not specifically limit as long as it has activity. The range of “1 to several” is likely to be an amino acid oxidase having high oxidative activity for the (R) -amine compound, and can be, for example, 1 or more and 30 or less, preferably Is 1 or more, 20 or less, more preferably 1 or more, 10 or less, further preferably 1 or more, 7 or less, more preferably 1 or more, 5 or less, particularly preferably 1 or more, 3 One or less, one or more, two or less, or about one.

  In the mutant amino acid oxidase (3), “sequence identity” in “amino acid sequence having at least 95% sequence identity to the amino acid sequence defined in (1) above” is the identity of the amino acid sequence. As long as the amino acid oxidase having an amino acid oxidase is an enzyme having an oxidative activity for the (R) -amine compound, it is not particularly limited. The sequence identity of the amino acid sequence is not particularly limited as long as it is 95% or more, preferably 96% or more, more preferably 97% or more, still more preferably 98% or more, still more preferably 99% or more, and particularly preferably 99%. .5% or more. In the present invention, the term “sequence identity” refers to the degree of amino acid identity with respect to each other of two or more amino acid sequences. Therefore, the higher the identity of two amino acid sequences, the higher the identity or similarity of those sequences. Whether or not two kinds of amino acid sequences have identity can be analyzed by direct comparison of the sequences, and specifically, can be analyzed using commercially available sequence analysis software or the like.

  In the above mutant amino acid oxidase (3), “mutation” in “however, the amino acids corresponding to the 228th and 283rd amino acid sequences in the amino acid sequence of the mutant amino acid oxidase shall not be mutated” Specifically, it means an amino acid deletion or substitution. That is, in the amino acid sequence of the mutant amino acid oxidase (3), the amino acids corresponding to the 228th and 283rd amino acids in the amino acid sequence of the mutant amino acid oxidase of (1), which is a criterion for determining sequence identity, It means that it is the same as the 228th and 283rd amino acids in the amino acid sequence of the mutant amino acid oxidase (1).

  In the mutant amino acid oxidase (3), the amino acids corresponding to the 228th and 283rd amino acids in the amino acid sequence of the mutant amino acid oxidase (1), which is a criterion for determining sequence identity, It can be examined by homology analysis. Specifically, using a commercially available sequence analysis software or the like, if the alignment analysis of the amino acid sequence to be analyzed is performed on the amino acid sequence shown in SEQ ID NO: 1 or the amino acid sequence of the mutant amino acid oxidase (1), It is possible to search for amino acids corresponding to the 228th and 283rd amino acids. Such alignment analysis techniques are widely known to those skilled in the art.

  In the above-mentioned mutant amino acid oxidase (2) or (3), “having oxidation activity for (R) -amine compound” means any (R) -amine compound, particularly (R) -amine compound It means that the target mutant amino acid oxidase exhibits an oxidative activity with respect to at least any one compound included in the range of (I). The specific conditions of the test may refer to examples described later.

  The origin of the mutant amino acid oxidase is not particularly limited as long as it belongs to the range defined in (1) to (3) above. For example, the mutant amino acid oxidase may be a recombinant protein produced by various genetic engineering techniques, a synthetic protein produced by chemical synthesis, or from the amino acid sequence shown in SEQ ID NO: 1. A mutant capable of producing the mutant enzyme is obtained by giving a mutagen to a specific species (for example, bacteria) having a gene homologue of the mutant amino acid oxidase, and the protein produced by the mutant is extracted. It may also be a protein produced by purification.

  When producing a recombinant protein that can be used in the method of the present invention by genetic engineering technology, a nucleic acid (DNA or RNA) encoding any one of the above-mentioned mutant amino acid oxidases (1) to (3) is prepared and expressed in various ways. By incorporating it into a vector, the mutant amino acid oxidase can be expressed. In preparing the nucleic acid encoding the mutant amino acid oxidase, the 228th and 283rd amino acids in the amino acid sequence shown in SEQ ID NO: 1 or the amino acid corresponding to the amino acid is the predetermined amino acid described in (1) above In the amino acid sequence of the mutant amino acid oxidase (2), amino acid deletion, substitution and / or addition, or in the amino acid sequence of the mutant amino acid oxidase (3) In order to prepare a nucleic acid encoding a protein having a predetermined identity with a sequence, for example, deletion, substitution and substitution of any base by error-prone PCR method, DNA shuffling method, various site-directed mutagenesis methods, etc. An insertion can be performed. The mutant amino acid oxidase can be produced by introducing the nucleic acid encoding the mutant amino acid oxidase thus prepared into an appropriate expression system.

  An expression system that can be used for producing the mutant amino acid oxidase is not particularly limited. For example, an expression vector that enables expression of a recombinant protein in various biological species (hosts) may be used. it can. As expression vectors that can be used, it is possible to use various expression vectors that allow protein expression in a host such as microorganisms such as bacteria and fungi (for example, yeasts), plants, insect cells, and mammalian cells. Virus vectors (including phage vectors) or plasmid vectors may be used. Alternatively, the protein may be produced using a cell-free protein expression system using rabbit reticulocyte lysate, wheat germ lysate, E. coli lysate or the like.

  When expressing the mutant amino acid oxidase in an expression system using a specific species as a host, a nucleic acid encoding the protein is mounted on a vector, and a host cell is transformed with the vector, followed by transformation. It can be prepared by a production method comprising culturing the host cell, accumulating the protein encoded by the gene in the culture, and collecting the accumulated protein.

  A nucleic acid encoding a protein that can be used in the present invention, a vector containing the nucleic acid, and a transformant transformed with the vector are one embodiment of the present invention. These nucleic acids, vectors and transformants can be prepared by those skilled in the art according to conventional methods once the amino acid sequence of the mutant amino acid oxidase is determined.

  The method for obtaining the nucleic acid encoding the mutant amino acid oxidase is not particularly limited. For example, the mutated amino acid oxidase or the gene having homology with the amino acid sequence shown in SEQ ID NO: 1 is isolated from various bacteria, nucleic acids encoding the gene are prepared, and the 228th and 283rd amino acids are prepared. A nucleic acid encoding the mutant amino acid oxidase may be produced by substituting an amino acid corresponding to the above. Further, the nucleic acid encoding the mutant amino acid oxidase is chemically synthesized based on the amino acid sequence shown in SEQ ID NO: 1 or the information of a known amino acid sequence having a certain identity with the amino acid sequence shown in SEQ ID NO: 1, It can be made by any method known to those skilled in the art, such as genetic engineering techniques or mutagenesis.

  Specifically, the nucleic acid encoding the mutant amino acid oxidase is, for example, a method of contacting a DNA encoding the amino acid represented by SEQ ID NO: 1 with a mutagen agent, a method of irradiating ultraviolet light, a genetic engineering This can be done by using a general technique. In addition, since site-directed mutagenesis, which is one of genetic engineering techniques, is a technique that can introduce a specific mutation at a specific position, in producing a nucleic acid encoding the above-mentioned mutant amino acid oxidase, It is useful for introducing site-specific mutations into

  For example, a material for producing a nucleic acid encoding the mutant amino acid oxidase can be obtained by PCR. For example, PCR is performed using a pair of primers designed to amplify DNA encoding the amino acid sequence of SEQ ID NO: 1 from genomic DNA of pig kidney. PCR reaction conditions can be set as appropriate. The amplified DNA fragment can be used as a material for producing a nucleic acid encoding the mutant amino acid oxidase. Furthermore, a vector obtained by cloning the amplified DNA fragment into an appropriate vector that can be amplified in a host such as E. coli is also used for producing a nucleic acid encoding the mutant amino acid oxidase. It can be used as a material.

  In the material for producing a nucleic acid encoding the mutant amino acid oxidase prepared as described above, various methods for introducing mutation into the base sequence (codon) encoding the amino acid corresponding to the 228th and 283rd amino acids. A nucleic acid encoding the above-mentioned mutant amino acid oxidase or a vector containing the nucleic acid can be produced by performing base substitution using The above-described operations such as preparation of the probe or primer, construction of the genomic library, screening of the genomic library, and cloning of the target gene are known to those skilled in the art.

  The nucleic acid encoding the mutant amino acid oxidase can be used in a state inserted in an appropriate vector. The type of vector used in the present invention is not particularly limited. For example, the vector may be a self-replicating vector (for example, a plasmid), or may be integrated into the host cell genome when introduced into the host cell. It may be replicated together with other chromosomes. Preferably the vector is an expression vector. In the expression vector, elements necessary for transcription (for example, a promoter and the like) are functionally linked to the nucleic acid. A promoter is a DNA sequence that exhibits transcriptional activity in a host cell, and can be appropriately selected depending on the type of host.

  In the vector, the nucleic acid encoding the mutant amino acid oxidase may be operably linked to an appropriate terminator as necessary. The vector containing the nucleic acid encoding the mutant amino acid oxidase may further have elements such as a polyadenylation signal (for example, derived from SV40 or adenovirus 5E1b region) and a transcription enhancer sequence (for example, SV40 enhancer). . The recombinant vector containing the gene for L-amino acid oxidase may further comprise a DNA sequence that allows the vector to replicate in the host cell, an example of which is the SV40 origin of replication (host cell is a mammalian cell). ).

  The vector containing the nucleic acid encoding the mutant amino acid oxidase may further contain a selection marker. Selectable markers include, for example, genes that lack their complement in host cells such as dihydrofolate reductase (DHFR) or Schizosaccharomyces pombe TPI genes, or such as ampicillin, kanamycin, tetracycline, chloramphenicol, Mention may be made of drug resistance genes such as neomycin or hygromycin. A person skilled in the art knows how to link the nucleic acid encoding the above mutant amino acid oxidase, a promoter, and optionally a terminator and / or a secretion signal sequence, respectively, and insert them into an appropriate vector.

  Furthermore, a transformant can be prepared by introducing a vector containing a nucleic acid encoding the mutant amino acid oxidase into an appropriate host. The host cell into which the vector is introduced may be any cell as long as the vector is replicated in the cell. Furthermore, in the case of producing a transformant that expresses the mutant amino acid oxidase, it is an arbitrary cell capable of expressing the mutant amino acid oxidase in addition to the replication of the vector. Examples of such host cells include bacteria, yeast, fungi and higher eukaryotic cells.

  The transformant is cultured in an appropriate nutrient medium under conditions that allow replication of the vector or conditions that allow expression of the mutant amino acid oxidase. In order to isolate and purify the mutant amino acid oxidase from the transformant culture (including the transformant and the culture medium) when the mutant amino acid oxidase is expressed, an ordinary protein isolation and purification method is used. May be used. For example, when the mutant amino acid oxidase is expressed in a dissolved state in the cell, the cell is collected by centrifugation after culturing, suspended in an aqueous buffer, and then disrupted by an ultrasonic disrupter or the like. A cell-free extract is obtained. From the supernatant obtained by centrifuging the cell-free extract, an ordinary protein isolation and purification method, that is, a solvent extraction method, a salting-out method using ammonium sulfate, a desalting method, a precipitation method using an organic solvent, Anion exchange chromatography using a resin such as diethylaminoethyl (DEAE) Sepharose, cation exchange chromatography using a resin such as S-Sepharose FF (Pharmacia), resin such as butyl sepharose and phenyl sepharose The above-mentioned mutant amino acid oxidase is used alone or in combination with the hydrophobic chromatography method used, gel filtration method using molecular sieve, affinity chromatography method, chromatofocusing method, electrophoresis method such as isoelectric focusing etc. Can be obtained as a purified sample.

  As the amino acid oxidase used in the present invention, in addition to the above-mentioned mutant amino acid oxidase, for example, an amino acid oxidase derived from kidneys such as pigs, an amino acid oxidase derived from snake venom, and Crotalus atrox, Trichoderma sp. , Pseudomonas sp. Amino acid oxidase derived from bacteria such as

  Examples of the amino acid oxidase derived from Crotalus atrox include any of the L-amino acid oxidases of (4) to (6) above. In addition, the definition, preferable numerical range, and the like of deletion, homology, and activity in the above (4) to (6) are the same as the definition and preferable numerical range in the above (1) to (3).

  The reaction conditions for the imine compound (II) by allowing amino acid oxidase to act on the amine compound (I) can be the same as in the enzyme reaction step of the deracemization method of the above step (A).

(C) Cyanation step Next, a cyanide ion is allowed to act on the produced imine compound (II) to obtain an α-amino nitrile compound (III).

  What is necessary is just to add cyanide ion to the reaction liquid as the salt. For example, sodium cyanide or potassium cyanide can be used.

  The amount of cyanide ion used may be appropriately adjusted, but it is preferable to use an amount capable of sufficiently cyanating the imine compound (II). For example, it is preferable to use about 2 times mol or more and 100 times mol or less with respect to amine compound (I) which is a raw material.

  The cyanation step may be performed simultaneously with the imination step (B). That is, cyanide ions may be added to the reaction solution of the above imination step (B), and the resulting imine compound (II) may be immediately converted to α-alkylamino nitrile (V).

  This application claims the benefit of priority based on Japanese Patent Application No. 2013-33707 filed on February 22, 2013. The entire contents of the specification of Japanese Patent Application No. 2013-33707 filed on February 22, 2013 are incorporated herein by reference.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. Of course, it is possible to implement them, and they are all included in the technical scope of the present invention.

  In addition, the (R) -amino acid oxidation activity and (R) -amine oxidation activity of the enzyme were measured as follows.

Test Example 1: Measurement of (R) -amino acid oxidation activity and (R) -amine oxidation activity of an enzyme (1) Preparation of reagent for measurement of (R) -amino acid oxidation activity

(2) Preparation of reagent for measuring (R) -amine oxidation activity It was prepared according to the formulation in Table 2.

(3) Measurement conditions for (R) -amino acid oxidation activity and (R) -amine oxidation activity (R) -amino acid oxidation activity and (R) -amine oxidation activity are the amounts of hydrogen peroxide produced by the oxidation of the substrate. The colorimetric method using the color developing solution shown in Table 1 or Table 2 was used. Specifically, in a 1 cm quartz cell, 10 times the volume of each reagent for measurement was added to the enzyme solution to make the total volume 1 mL, reacted at 30 ° C. for 1 hour, and the absorbance at 505 nm was measured with a microplate reader. In the blank, distilled water was added instead of the substrate. Each oxidation activity was calculated from the obtained absorbance change based on the following formula. In this test example, 1U was defined as the amount of enzyme that produces 1 μmol of H ₂ O ₂ per minute using (R) -phenylalanine or (R) -α-methylbenzylamine as a substrate.

(4) Calculation formula of (R) -amino acid oxidation activity and (R) -amine oxidation activity Activity value (U / mL) = {ΔAbs505 / min (ΔAbs505sample-ΔAbs505blank) × 1 (mL) × dilution factor} / {4 .66 × 1.0 (cm) × 0.1 (mL)}
1 (mL): total liquid volume 4.66: mmol extinction coefficient 1.0 cm: optical path length of cell 0.1 (mL): enzyme sample liquid volume (5) Measurement of specific activity Enzyme content per unit liquid volume, Measurement was performed using a Bradford method protein assay kit (manufactured by Biorad). By measuring the activity value per unit liquid volume by the above activity measurement method, and dividing the activity value per unit liquid volume by the enzyme content per unit liquid volume, (R) -amino acid oxidation activity and (R) -amine oxidation Specific activity related to activity was determined.

Reference Example 1: Preparation of mutant (R) -amino acid oxidase (1) Preparation of porcine kidney-derived (R) -amino acid oxidase gene A porcine kidney-derived (R) -amino acid oxidase gene was prepared by assembly PCR. Table 3 shows the primers (SEQ ID NOs: 3 to 35) used.

The composition of the assembled PCR reaction solution was 35 μL of water, 5 μL of 10 × Ex Taq buffer, 5 μL of 2 mM dNTP, 2 μL of a 100 pmol / μL mixture of primers shown in Table 3, and Ex Taq 5 unit. The PCR reaction conditions were (i) 96 ° C. for 20 seconds, (ii) 50 ° C. for 30 seconds, (iii) 55 ° C. for 1.5 minutes, and (ii) to (iii) for 35 cycles.

  Escherichia coli was transformed with the PCR product. The composition of the ligation reaction was 5 μL of PCR product, 1 μL of pT7 Blue T-Vector (Novagen), and 6 μL of ligation mix (Takara Bio), and reacted at 16 ° C. for 30 minutes. To 100 μL of competent cells of E. coli JM109, 12 μL of the ligation reaction solution was added and transformed by the heat shock method. Several colonies grown in LB medium (1.0% polypeptone, 0.5% yeast extract, 1.0% NaCl) containing 80 μg / mL ampicillin were selected and extracted with plasmid, and 0.7% agarose The presence or absence of the insert was confirmed by electrophoresis.

  Separately, the porcine kidney (derived R) -amino acid oxidase gene sequence was sequenced. Specifically, a sequencing reaction was performed using a universal primer T7 promoter primer and a U-19mer primer for sequencing both strands of the gene. The reaction solution composition is 1.6 μL of any of the above primers, 1.6 μL of template DNA, 1 μL of BigDye premix solution, 1.6 μL of 5 × BigDye sequencing buffer and 2.8 μL of sterile water, The total volume was adjusted to 10 μL. The conditions of the PCR reaction were (i) 96 ° C. for 2 minutes, (ii) 96 ° C. for 10 seconds, (iii) 50 ° C. for 5 seconds, (iv) 60 ° C. for 4 minutes, (v) (ii) to ( iv) 25 times, and (vi) 5 minutes at 72 ° C. 1 μL of 0.125 M EDTA and 35 μL of ethanol were added to the PCR product, left at room temperature for 15 minutes, and then precipitated by centrifugation (15,000 rpm, 8 minutes, 4 ° C.). After discarding the supernatant, 70% ethanol was added and stirred, and then centrifuged again. Thereafter, 20 μL of Hi Di Formatide was added, and after heating at 100 ° C. for 5 minutes and then rapidly cooling with ice water, the base sequence was decoded with Applied Biosystems 3500 Genetic Analyzer. The obtained sequence data was analyzed by Genetyx, and the fragments amplified with the respective primers were ligated. The amino acid sequence corresponding to the decoded porcine kidney-derived (R) -amino acid oxidase gene sequence is shown in SEQ ID NO: 1.

  Next, the porcine kidney-derived (R) -amino acid oxidase gene was amplified. Specifically, PCR was performed using the plasmid obtained by the above cloning as a template DNA. The composition of the PCR reaction solution was as follows: water 35 μL, 10 × Ex Taq buffer 5 μL, 2 mM dNTP 5 μL, 100 pmol / μL Primer 5 (5′-tttgaattctaaggaggacttagctgtgtgtgtgtgtgtggtgmol-3′L, sequence number 6′L aataagctttcagagggtgggatgggtggcat-3 ′, SEQ ID NO: 37) 1 μL, template DNA 100 ng and Ex Taq 5 unit. Primer 5 and primer 6 were provided with BamHI and HindIII restriction enzyme sites, respectively. The conditions for the PCR reaction were (i) 98 ° C. for 5 minutes, (ii) 96 ° C. for 20 seconds, (iii) 50 ° C. for 30 seconds, (iv) 55 ° C. for 1.5 minutes, and (ii) to (ii) Up to iv) was 28 cycles.

  The obtained porcine kidney-derived (R) -amino acid oxidase gene was used to transform E. coli. That is, 1 μL BamHI and 1 μL HindIII were added to 5 μL of the PCR product obtained by the above PCR reaction, and incubated at 37 ° C. for 1 hour to perform restriction enzyme treatment. Ligation reaction was 5 μL of DNA, 1 μL of pUC18 (treated with the same restriction enzyme as the amplified gene) and 6 μL of ligation Mix, and incubated at 16 ° C. for 3 hours to prepare plasmid pDAO. The obtained plasmid pDAO was introduced into E. coli by the heat shock method.

  The (R) -amino acid oxidase gene was expressed in the transformed E. coli and its activity was measured. Inoculate transformed E. coli in 5 mL of LB medium (1.0% polypeptone, 0.5% yeast extract, 1.0% NaCl, pH 7.0) containing 80 μg / mL ampicillin and 1 mM IPTG. The cells were cultured at 24 ° C. for 24 hours. The cells were collected by centrifugation (15,000 rpm, 5 minutes, 4 ° C.), washed with 10 mM potassium phosphate buffer containing 0.1% 2-mercaptoethanol, and suspended in 1 mL of the same buffer. The obtained bacterial cell solution was sonicated for 15 minutes, and the supernatant obtained by centrifugation (15,000 rpm, 15 minutes, 4 ° C.) was used as a cell-free extract. (R) -Amino acid oxidation activity and (R) -amine oxidation activity were measured by the activity measurement method of Test Example 1.

(2) Modification of substrate specificity of porcine kidney-derived (R) -amino acid oxidase Pay attention to 228th tyrosine and 283rd arginine of amino acid sequence (SEQ ID NO: 1) of porcine kidney-derived wild-type (R) -amino acid oxidase Then, a saturation mutation was introduced into each amino acid residue. Specifically, using Quikchange Multi site-directed mutagenesis kit (manufactured by Agilent Technologies), using plasmid pDAO prepared in Reference Example 1 (1) as a template and the following primers (SEQ ID NOs: 38 to 41) PCR was performed.

5'-agaggcatctacaactctccannnatcattccagggctgc-3 '
5'-gcagccctggaatgatnnntggagagttgtagatgcctct-3 '
5'-tgaatatactggcttcnnnccagtacgccccca-3 '
5'-tgggggcgtactggnnngaagccagtatattca-3 '
Escherichia coli JM109 was transformed by the heat shock method using the obtained PCR product. Using a 96-well plate, the cells were cultured at 37 ° C. for 24 hours in LB medium containing 0.5 mM IPTG and 80 μg / mL ampicillin, and then collected by centrifugation. The recovered E. coli was suspended in 50 mM KPB (pH 8), and a cell-free extract was prepared by ultrasonic disruption.

  With respect to the cell-free extract, (R) -amine oxidation activity was measured according to Test Example 1. Further, using the mutant enzyme gene obtained above as a template, saturation mutation was performed on the 228th tyrosine in the same manner, and (R) -amine oxidation activity was measured. The results were obtained when the specific activity 0.11 U / mg when oxidizing (R) -phenylalanine ((D) -phenylalanine) with porcine kidney-derived (R) -amino acid oxidase (wild type) was 100%. The relative activity is shown in FIG. In FIG. 1, the black-colored columns are not the case where (R) -α-methylbenzylamine is used as a substrate, but the results when (R) -phenylalanine is used as a substrate. When (R) -α-methylbenzylamine was oxidized using wild-type (R) -amino acid oxidase, the progress of the reaction was not observed, and the specific activity was almost zero.

As shown in FIG. 1, the oxidative activity of (R) -α-methylbenzylamine was confirmed in the mutant enzyme in which the 283rd arginine was substituted with glycine, alanine or cysteine . Further, in any of the mutant enzymes in which the 283rd arginine is substituted with glycine, alanine or cysteine , the oxidation activity of (R) -α-methylbenzylamine in the mutant enzyme in which the 228th tyrosine is substituted with leucine. An improvement was seen. In particular, the mutant enzyme (SEQ ID NO: 2) in which the 283rd arginine was replaced with glycine and the 228th tyrosine was replaced with leucine showed excellent (R) -amine oxidation activity compared to the wild-type enzyme.

Reference Example 2: Purification of Pig Kidney-Derived Mutant (R) -Amino Acid Oxidase Mutant enzyme obtained by replacing the 283rd arginine obtained in Reference Example 1 above with glycine and the 228th tyrosine with leucine (SEQ ID NO: 2) ) Was purified. Hereinafter, the potassium phosphate buffer (KPB) used for purification contains 0.1% 2-mercaptoethanol.

(1) Preparation of cell-free extract Escherichia coli transformed with a gene encoding a mutant enzyme in which 283rd arginine is replaced with glycine and 228th tyrosine is replaced with leucine in an LB medium containing 5 mL of 80 mM ampicillin Was pre-cultured at 200 rpm and 37 ° C. for 24 hours. The preculture was inoculated into 500 mL of LB medium containing 80 mM ampicillin and 1 mM IPTG (total volume 5 L), and cultured with shaking at 300 rpm and 37 ° C. for 1 day using a 2 L baffle. The cells were collected by centrifuging at 8,000 rpm and 4 ° C. for 5 minutes using a large centrifuge, washed with 10 mM KPB (pH 8.0), and then 5 L of cells were suspended in 80 mL of 10 mM KPB. It became cloudy. The supernatant obtained by sonicating 80 mL of the cell solution for 15 minutes and centrifuging at 8,000 rpm at 4 ° C. for 15 minutes was used as a cell-free extract.

(2) Ammonium sulfate fraction The above cell-free extract was added to ice with stirring with a stirrer so that ammonium sulfate was saturated to 20%, stirred for 30 minutes, and then stirred at 8,000 rpm using a large centrifuge. The supernatant was obtained by centrifuging at 4 ° C. for 15 minutes. Ammonium sulfate was added to the obtained supernatant so as to be 35% saturated, and centrifuged under the same conditions as above to obtain a precipitate. To the resulting precipitate, 10 mL of 10 mM KPB (pH 8.0) was added and suspended, and dialyzed overnight against 5 L of the same buffer (× 2).

(3) Anion exchange column chromatography The column was filled with 100 mL of DEAE-Toyopearl resin equilibrated with 10 mM KPB, and the dialyzed enzyme solution was adsorbed. After washing the column with 100 mL of 10 mM KPB, the NaCl concentration was gradually increased with a gradient using 100 mL of 10 mM KPB and 100 mL of 10 mM KPB containing 50 mM NaCl to elute the enzyme. Using a fraction collector, fractions were collected in 20 mL aliquots, and the fractions showing activity were collected and dialyzed overnight against 10 mM KPB.

(4) Hydrophobic column chromatography The column was filled with 10 mL of Butyl-Toyopearl resin equilibrated with 10 mM KPB containing 20% ammonium sulfate, and an enzyme solution containing 20% ammonium sulfate was adsorbed. After washing the column with 10 mM KPB containing 50 mL of ammonium sulfate, the concentration of ammonium sulfate was gradually lowered with 10 mM KPB and 10 mM KPB containing 50 mL of 20% ammonium sulfate to elute the enzyme. Fractions with recognized activity were collected and dialyzed overnight against 10 mM KPB. Table 4 shows the enzyme amount and (R) -amine oxidation activity in each purification step.

(5) Confirmation of purity of porcine kidney-derived mutant (R) -amino acid oxidase by SDS polyacrylamide gel electrophoresis As electrophoresis gel, 5.25 mL of 36% acrylamide, 0.68 M Tris-HCl buffer (pH 8.8) 8.25 mL, 1% SDS 1.58 mL, 10% TEMED 187 μL, 2% APS 562 μL of gel 5 μL, 36% polyacrylamide 0.5 mL, 0.179 M Tris-HCl (pH 6.8) 3.5 mL 1% SDS 0.5 mL, 10% TEMED 125 μL, 2% APS 375 μL of the concentrated gel layered, buffer solution (glycerol 200 μL, 1M Tris-HCl (pH 8.0) 40 μL, water 360 μL, 2-mercaptoethanol 200 μL and 10% SDS 200 μL ) And purified enzyme samples 10μL were mixed in equal amounts, in running buffer (Tris 3.0 g, glycine 14.1g and SDS10g), was subjected to electrophoresis 20mA. Then, it was stained with a protein staining solution (CBB 2.5 g, methanol 500 mL, acetic acid 50 mL and water 450 mL) for 1 hour, and decolorized with a decoloring solution (methanol: acetic acid: water = 3: 1: 6) until the band became clear. As molecular weight markers, phosphorylase (97,200), bovine serum albumin (66,409), Ovalbumin (44,287), carbonic anhydrase (29,000), soybean trypsin inhibitor (20,100) and 14 (100) (Takara Bio Inc.) containing A photograph of the obtained SDS-PAGE is shown in FIG.

Reference Example 3 Substrate Specificity of Pig Kidney-Derived Variant (R) -Amino Acid Oxidase In the measurement conditions for (R) -amine oxidation activity in Test Example 1 above, (R) -α-methylbenzylamine was used as a substrate compound. Instead, various amines or amino acids were used to measure enzyme activity. The specific activity when α-methylbenzylamine is used as a substrate is compared with the specific activity when each substrate is used, and the relative activity with respect to other substrates when the activity with respect to α-methylbenzylamine is 100%. Asked. The results are shown in Table 5.

As shown in Table 5, the obtained mutant (R) -amino acid oxidase has no activity on phenylalanine, which is a substrate for wild-type (R) -amino acid oxidase. Moreover, the activity with respect to (S) -α-methylbenzylamine derivatives, (R) -α-methylbenzylamine having a methoxy group or a methyl group introduced as a substituent on a phenyl group, a cyclohexane compound, or an achiral compound is low. On the other hand, the (R) -α-methylbenzylamine derivative showed extremely high oxidation activity.

Reference Example 4: Optimum temperature of porcine kidney-derived mutant (R) -amino acid oxidase Using the measurement method shown in Test Example 1 above, the temperature was changed from 20 ° C. to 60 ° C. in 5 ° C. increments. Mutant (R) -amine oxidation activity was measured. The results are shown in FIG.

  As shown in FIG. 3, the optimum temperature of the obtained porcine kidney-derived mutant (R) -amino acid oxidase was 45 ° C.

Reference Example 5: Thermal stability of porcine kidney-derived mutant (R) -amino acid oxidase After heat treatment of the obtained porcine kidney-derived mutant (R) -amino acid oxidase at each temperature from 20 ° C to 70 ° C for 30 minutes The (R) -amine oxidation activity was measured using the measurement method shown in Test Example 1 above. The results are shown in FIG.

  As shown in FIG. 4, the obtained porcine kidney-derived mutant (R) -amino acid oxidase showed 86% residual activity by heat treatment at 45 ° C. and 46% residual activity by heat treatment at 50 ° C. From these results, it was revealed that the obtained porcine kidney-derived mutant (R) -amino acid oxidase is relatively stable to heat.

  Reference Example 6: Optical resolution of (S) -α-methylbenzylamine from (RS) -α-methylbenzylamine

Using the mutant (R) -amino acid oxidase purified in Reference Example 2, optical resolution of α-methylbenzylamine was performed. 1 mL of a reaction solution containing 50 mM KPB (pH 8.0), 10 mM (RS) -α-methylbenzylamine, and the mutant (R) -amino acid oxidase 1.5 U obtained in Reference Example 2 was incubated at 30 ° C. . After 5, 10, 15, 30, 60, 90, and 120 minutes from the start of the reaction, reaction solution samples were collected and analyzed by the following HPLC.

Analysis condition column: CROWNPAK CR (+) (manufactured by Daicel)
Mobile phase: 60 mM perchloric acid containing 5% methanol Flow rate: 0.8 mL / min
Detection wavelength: 200nm
Column temperature: 30 ° C
The retention times of (R)-and (S) -α-methylbenzylamine are described below.

(S) -α-methylbenzylamine: 11.6 minutes (R) -α-methylbenzylamine: 12.6 minutes The results are shown in FIG. As shown in FIG. 5, (R) -α-methylbenzylamine (“●” in FIG. 5) is selectively oxidized and converted to methylbenzylimine by the obtained mutant amino acid oxidase, and further in an aqueous solvent. It is converted to stable acetophenone, and is almost 0% after 60 minutes from the start of the reaction. In contrast, the concentration of (S) -α-methylbenzylamine (“◯” in FIG. 5) is maintained at about 5 mM. Since α-methylbenzylamine is different from methylbenzylimine and acetophenone, it can be easily separated by column chromatography or the like. These results demonstrated that (S) -α-methylbenzylamine can be obtained from (RS) -α-methylbenzylamine by the obtained mutant amino acid oxidase.

  Reference Example 7: Deracemization of α-methylbenzylamine using porcine kidney-derived mutant (R) -amino acid oxidase

Using the mutant (R) -amino acid oxidase purified in Reference Example 2, α-methylbenzylamine was deracemized. 30 mL of a reaction solution containing 50 mM KPB (pH 8.0), 5 mM (RS) -α-methylbenzylamine, 250 mM sodium borohydride, and 3U of the mutant (R) -amino acid oxidase 3U obtained in Reference Example 2 above. Incubated at 0 ° C. Samples of the reaction solution were collected in a timely manner until 180 minutes after the start of the reaction, and analyzed by HPLC under the conditions shown in Reference Example 6 above. The results are shown in FIG. As shown in FIG. 6, (R) -α-methylbenzylamine is selectively oxidized and converted to methylbenzylimine by the obtained mutant amino acid oxidase, and its concentration (“●” in FIG. 6) is almost 0%. Became. In contrast, (S) -α-methylbenzylamine in the racemate (RS) does not react, and the methylbenzylimine is reduced again to (RS) -α-methylbenzylamine by the presence of a reducing agent. Therefore, the concentration (“◯” in FIG. 6) approached 5 mM, which is the concentration of the original racemate. From these results, it was demonstrated that (S) -α-methylbenzylamine can be efficiently obtained from (RS) -α-methylbenzylamine by the combined use of the obtained mutant amino acid oxidase and a reducing agent.

Example 1: Conversion of α-methylbenzylamine to 2-amino-2-propanenitrile using a mutant amino acid oxidase

Using the mutant (R) -amino acid oxidase purified in Reference Example 2, an oxidative cyanide addition reaction of α-methylbenzylamine was performed. 1 mL of a reaction solution containing 50 mM KPB (pH 8.0), 10 mM (R) -α-methylbenzylamine, 30 mM KCN, and the mutant (R) -amino acid oxidase 2U according to the present invention obtained in Reference Example 2 above, Incubated for 60 minutes at 30 ° C. A sample was collected during the reaction and analyzed by HPLC under the conditions shown in Reference Example 6 above. The results are shown in FIG.

  As shown in FIG. 7, it was shown that 2-amino-2-phenylpropanenitrile can be synthesized via an imine intermediate by oxidizing (R) -α-methylbenzylamine with the enzyme of the present invention in the presence of 30 mM KCN. . The substance was identified by the column retention time by HPLC of the standard product 2-amino-2-phenylpropanenitrile.

  Example 2: Oxidative cyanation reaction using porcine kidney-derived D-amino acid oxidase

An oxidative cyanide addition reaction of D-phenylalanine was performed using porcine kidney-derived D-amino acid oxidase. 1 mL of a reaction solution containing 100 mM potassium phosphate buffer (KPB), 10 mM D-phenylalanine, 100 mM KCN, and 87 mU of porcine kidney-derived D-amino acid oxidase was incubated at 30 ° C. for 90 minutes. A sample was collected during the reaction and analyzed by the following LC-MS.

Analysis conditions Column: COSMOSIL 2.5C18-MS-II (manufactured by Nacalai Tesque)
Mobile phase: 5% aqueous methanol solution containing 0.1% formic acid Flow rate: 0.2 mL / min
Detection wavelength: 254 nm
Column temperature: 30 ° C
The retention times of D-phenylalanine and 2-amino-2-cyano-phenylpropanoic acid are described below.

D-phenylalanine: 5.5 minutes 2-amino-2-cyano-phenylpropanoic acid: 11.2 minutes FIG. 8 (A) shows an HPLC chart of a solution containing D-phenylalanine and KPB, and FIG. 8 (B). Shows an HPLC chart of a solution containing D-phenylalanine, KPB, and porcine kidney-derived D-amino acid oxidase, and FIG. 8C shows an HPLC chart of the reaction solution after the above reaction. Moreover, the result of having analyzed the peak for 11 minutes in the HPLC chart of FIG. 8 with a mass spectrum in FIG. 9 is shown.

  From the molecular weight peak shown in FIG. 9 and the MS-MS fragment, the main product obtained by the above reaction is judged to be the target compound. Therefore, it became clear that the α-amino nitrile compound can be efficiently produced from the amine compound by the method of the present invention.

  Example 3: Oxidative cyanation reaction using L-amino acid oxidase derived from Crotalus atrox

An oxidative cyanide addition reaction of L-phenylalanine was performed using L-amino acid oxidase derived from Crotalus atrox. 1 mL of a reaction solution containing 100 mM potassium phosphate buffer (KPB), 10 mM L-phenylalanine, 100 mM KCN, and Crotalus atox-derived L-amino acid oxidase 8U was incubated at 30 ° C. for 90 minutes. A sample was collected during the reaction and analyzed under the analysis conditions shown in Example 2 above. FIG. 10 shows the HPLC chart of the reaction solution, and FIG. 11 shows the result of analyzing the peak of 10 minutes in the HPLC chart of FIG. 10 by mass spectrum.

  As shown in FIGS. 10 and 11, it was proved that L-phenylalanine was oxidatively cyanated using L-amino acid oxidase and KCN to obtain an α-amino nitrile compound.

  Example 4: Production of 2-amino-2-propane by the process of the present invention

Using the mutant (R) -amino acid oxidase purified in Reference Example 2, an oxidative cyanide addition reaction of α-methylbenzylamine was performed. 1 mL of a reaction solution containing 100 mM HCl, 5 mM (R) -α-methylbenzylamine, 150 mM KCN, and the mutant (R) -amino acid oxidase 8U according to the present invention obtained in Example 3 above, at 20 ° C. for 90 minutes. Incubated. Samples were collected over time during the reaction and analyzed by the following HPLC. The results are shown in FIG.

Analysis conditions Column: CROWNPAK CR (+) (manufactured by Daicel)
Mobile phase: 60 mM perchloric acid containing 5% methanol Flow rate: 0.8 mL / min
Detection wavelength: 200nm
Column temperature: 30 ° C
The retention times of (R)-and (S) -α-methylbenzylamine are described below.

(S) -α-methylbenzylamine: 11.2 minutes (R) -α-methylbenzylamine: 14.4 minutes (S) -2-amino-2-propanenitrile: 9.0 minutes (R) -2 -Amino-2-propanenitrile: 9.8 min As shown in FIG. 12, (R) -α-methylbenzylamine is selectively oxidized and converted to methylbenzylimine by the enzyme of the present invention, and its concentration (in FIG. 12) “●”) was almost 0%. Racemic 2-amino-2-propanenitrile was produced by chemically adding KCN to the produced methylbenzylimine. The concentration (“◯” in FIG. 12) reached 4 mM. As a side reaction, 1 mM of acetophenone was produced (“▲” in FIG. 12). From these results, it was demonstrated that 2-amino-2-propanenitrile can be efficiently obtained from (R) -α-methylbenzylamine by the combined use of the enzyme of the present invention and cyanide.

  An amino acid having a substituent different from hydrogen at the α-position and an α-amino nitrile compound, which is a derivative thereof, are expected to be used as an intermediate for pharmaceuticals and the like, and are expected to be commercialized because they can be produced efficiently according to the present invention. It is.

Claims (7)

A method for producing an α-amino nitrile compound comprising:
An iminization step in which an amino acid oxidase is allowed to act on an amine compound represented by the following formula (I) to form an imine compound represented by the following formula (II):
[Wherein, R ¹ represents a C _6-12 aryl group which may have a substituent, a heteroaryl group which may have a substituent, or a carboxy group, and R ² represents C _1-6. An alkyl group, a C _6-12 aryl-C _1-6 alkyl group optionally having a substituent on the C _6-12 aryl group, or a hetero optionally having a substituent on the heteroaryl group An aryl-C _1-6 alkyl group, the substituent which the C _6-12 aryl group and heteroaryl group may have is a halogen atom]; and a cyanide ion acting on the imine compound (II) A cyanation step of obtaining an α-alkylamino nitrile compound represented by the following formula (III) by
A method comprising adding the cyanide ion to the reaction solution of the imination step.
[Wherein R ¹ and R ² are as defined above] The method according to claim 1, wherein the amino acid oxidase is a mutant amino acid oxidase of any one of (1) to (3) below.
(1) A mutant amino acid oxidase having an amino acid sequence in which the 228th amino acid is substituted with tyrosine or leucine and the 283rd arginine is substituted with glycine, alanine or cysteine in the amino acid sequence shown in SEQ ID NO: 1;
(2) A mutation having an amino acid sequence in which one or several amino acids are deleted, substituted and / or added in the region excluding the 228th and 283rd amino acids in the amino acid sequence defined in (1) above A variant amino acid oxidase which is an amino acid oxidase and has an oxidation activity for (R) -amine compounds; or (3) an amino acid having 95% or more sequence identity to the amino acid sequence defined in (1) above Mutant amino acid oxidase having a sequence and oxidative activity against (R) -amine compound (however, in the amino acid sequence of the mutant amino acid oxidase, the amino acids corresponding to the 228th and 283rd amino acid sequences are not mutated) And).   The method according to claim 2, wherein in the mutant amino acid oxidase (1), the 228th amino acid is leucine and the 283rd arginine is glycine. R ¹ represents an optionally substituted C _6-12 aryl group or an optionally substituted heteroaryl group, and R ² represents a C _1-6 alkyl group. The method described in 1.   The method according to claim 2, wherein R form is used as the amine compound (I).   The method according to claim 1, wherein L-amino acid oxidase derived from Crotalus atrox is used as the amino acid oxidase. The method according to claim 1, wherein the L-amino acid oxidase of any one of (4) to (6) below is used as the amino acid oxidase.
(4) L-amino acid oxidase having the amino acid sequence of SEQ ID NO: 42;
(5) A mutant amino acid oxidase having an amino acid sequence in which one or several amino acids are deleted, substituted and / or added in the amino acid sequence defined in (4) above, and has an oxidative activity against L-amino acids Or (6) a mutant having an amino acid sequence having a sequence identity of 95% or more with respect to the amino acid sequence defined in (4) above and having an oxidative activity for L-amino acid oxidase Amino acid oxidase.