WO2017115826A1 - 新規β-ガラクトシダーゼ - Google Patents
新規β-ガラクトシダーゼ Download PDFInfo
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- WO2017115826A1 WO2017115826A1 PCT/JP2016/089001 JP2016089001W WO2017115826A1 WO 2017115826 A1 WO2017115826 A1 WO 2017115826A1 JP 2016089001 W JP2016089001 W JP 2016089001W WO 2017115826 A1 WO2017115826 A1 WO 2017115826A1
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- C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
- C12N9/00—Enzymes; Proenzymes; Compositions thereof; Processes for preparing, activating, inhibiting, separating or purifying enzymes
- C12N9/14—Hydrolases (3)
- C12N9/24—Hydrolases (3) acting on glycosyl compounds (3.2)
- C12N9/2402—Hydrolases (3) acting on glycosyl compounds (3.2) hydrolysing O- and S- glycosyl compounds (3.2.1)
- C12N9/2468—Hydrolases (3) acting on glycosyl compounds (3.2) hydrolysing O- and S- glycosyl compounds (3.2.1) acting on beta-galactose-glycoside bonds, e.g. carrageenases (3.2.1.83; 3.2.1.157); beta-agarase (3.2.1.81)
- C12N9/2471—Beta-galactosidase (3.2.1.23), i.e. exo-(1-->4)-beta-D-galactanase
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- C07H—SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
- C07H3/00—Compounds containing only hydrogen atoms and saccharide radicals having only carbon, hydrogen, and oxygen atoms
- C07H3/06—Oligosaccharides, i.e. having three to five saccharide radicals attached to each other by glycosidic linkages
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- C12N15/00—Mutation or genetic engineering; DNA or RNA concerning genetic engineering, vectors, e.g. plasmids, or their isolation, preparation or purification; Use of hosts therefor
- C12N15/09—Recombinant DNA-technology
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- C12N5/00—Undifferentiated human, animal or plant cells, e.g. cell lines; Tissues; Cultivation or maintenance thereof; Culture media therefor
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- C12P19/00—Preparation of compounds containing saccharide radicals
- C12P19/14—Preparation of compounds containing saccharide radicals produced by the action of a carbohydrase (EC 3.2.x), e.g. by alpha-amylase, e.g. by cellulase, hemicellulase
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- C12Y—ENZYMES
- C12Y302/00—Hydrolases acting on glycosyl compounds, i.e. glycosylases (3.2)
- C12Y302/01—Glycosidases, i.e. enzymes hydrolysing O- and S-glycosyl compounds (3.2.1)
- C12Y302/01023—Beta-galactosidase (3.2.1.23), i.e. exo-(1-->4)-beta-D-galactanase
Definitions
- the present invention relates to a novel ⁇ -galactosidase.
- the ⁇ -galactosidase of the present invention is used, for example, for producing a galactooligosaccharide known as an intestinal bifidobacterial growth factor.
- This application claims priority based on Japanese Patent Application No. 2015-257705 filed on Dec. 29, 2015, the entire contents of which are incorporated by reference.
- ⁇ -galactosidase (EC 3.2.1.23) is an enzyme that hydrolyzes ⁇ -D-galactoside bonds to release D-galactose, and is generally present in microorganisms, animals and plants.
- ⁇ -galactosidase also known as lactase, is an enzyme for the production of whey syrup from low-lactose milk for lactose intolerance and whey produced as a by-product during cheese production, or a drug or supplement for lactose intolerant patients It is used as an active ingredient.
- ⁇ -galactosidase also has the ability to transfer galactose residues with ⁇ bonds, and a method for producing galactooligosaccharides (oligosaccharides having galactose residues) using this ability is known.
- Aspergillus oryzae, yeast Sporobolomyces singularis, Kluyveromyces lactis, Cryptococcus lauren Known are Cryptococcus laurentii, Bacillus circulans, Sterigmatomyces elviae (see, for example, Patent Documents 1 to 3).
- an object of the present invention is to provide a novel ⁇ -galactosidase useful in industrial use, particularly in the production of oligosaccharides, and its use.
- the present inventor screened a wide variety of microorganisms.
- the present inventors have succeeded in finding a cryptococcus microorganism (wild strain) that produces ⁇ -galactosidase having a high optimum temperature, excellent heat resistance, and excellent sugar transfer activity.
- the ⁇ -galactosidase produced by the strain was purified and its characteristics were examined in detail. As a more advantageous characteristic, it was stable in an acidic pH range, and in the case of acting lactose as a substrate, enteric bifidobacteria It has been found that a linear oligosaccharide that is particularly useful as a growth factor is efficiently produced.
- the ⁇ -galactosidase is exocrine and is advantageous from the point of production.
- wild-type enzyme a novel ⁇ -galactosidase having extremely high utility value as an enzyme for producing oligosaccharides.
- repeated mutations by UV treatment and subsequent screening of the above microorganism succeeded in creating useful mutants.
- mutant enzyme In examining the characteristics of the obtained mutant strain, a total of three types of ⁇ -galactosidase (mutant enzyme) were found from the two mutant strains. Further studies were conducted and the amino acid sequence of these mutant enzymes was successfully identified. These enzymes are all fragments (parts) of the wild-type enzyme and did not exist in nature. More specifically, it is a mutant enzyme in which the N-terminal amino acid sequence of the wild-type enzyme is partially deleted, and has improved stability (pH, temperature) compared to the wild-type enzyme. The following invention has been completed based on the above-mentioned results.
- a ⁇ -galactosidase comprising the amino acid sequence of any one of SEQ ID NOs: 1 to 4, or an amino acid sequence 80% or more identical to the amino acid sequence.
- ⁇ -galactosidase according to any one of [1] to [3], comprising an amino acid sequence having a length not exceeding the length of the sequence of SEQ ID NO: 1.
- ⁇ -galactosidase having the following enzymatic chemistry, (1) Action: It has lactose-degrading activity and galactosyl transfer activity, and is more active to ⁇ -1,4 bond than ⁇ -1,6 bond, ⁇ -1,3 bond or ⁇ -1,2 bond. The metastatic activity is dominant, (2) Optimal temperature: 70 °C (3) Molecular weight without sugar chain: about 104 kDa, about 64 kDa, or about 61 kDa (by SDS-PAGE).
- ⁇ -galactosidase according to [5] further having the following enzymatic chemistry: (4) Optimal pH: 4-5 (5) pH stability: stable in the range of pH 2-8 (40 ° C, 30 minutes), (6) Temperature stability: stable in the range of 30 ° C to 60 ° C (pH 6.0, 30 minutes).
- ⁇ -galactosidase according to [5] further having the following enzymatic chemistry: (4) Optimal pH: 4-5 (5) pH stability: stable in the range of pH 2-9 (40 ° C, 30 minutes), (6) Temperature stability: stable in the range of 30 ° C to 65 ° C (pH 6.0, 30 minutes).
- [8] The ⁇ -galactosidase according to any one of [1] to [7], which is derived from Cryptococcus terrestris.
- [9] The ⁇ -galactosidase according to [8], wherein Cryptococcus terrestris is MM13-F2171 strain (Accession number: NITE BP-02177) or APC-6431 strain (Accession number: NITE BP-02178).
- An enzyme agent comprising the ⁇ -galactosidase according to any one of [1] to [9] as an active ingredient.
- ⁇ -galactosidase gene comprising any DNA selected from the group consisting of the following (a) to (c): (a) DNA encoding any one of the amino acid sequences of SEQ ID NOs: 1 to 4; (b) DNA comprising any one of the nucleotide sequences of SEQ ID NOS: 5 to 8 and 16; (c) DNA encoding a protein having a base sequence equivalent to any one of SEQ ID NOs: 5 to 8 and 16, and having ⁇ -galactosidase activity.
- a recombinant DNA comprising the ⁇ -galactosidase gene according to [11].
- a method for producing ⁇ -galactosidase comprising the following steps (1) and (2): (1) culturing Cryptococcus terrestris; (2) A step of recovering ⁇ -galactosidase from the cultured medium and / or cells after culturing. [15] The production method of [14], wherein Cryptococcus terrestris is MM13-F2171 strain or a mutant strain thereof. [16] A process for producing ⁇ -galactosidase, comprising the following steps (i) and (ii): (i) culturing the microorganism according to [13] under conditions under which a protein encoded by the gene is produced; (ii) recovering the produced protein.
- oligosaccharides or polysaccharides having at least one of ⁇ -1,3 bond, ⁇ -1,4 bond and ⁇ -1,6 bond [1] to [9] A method for producing an oligosaccharide, comprising the step of allowing ⁇ -galactosidase according to any one of the above to act.
- the production method according to [17] or [18], wherein the reaction temperature in the step is 30 ° C to 75 ° C.
- M molecular weight marker
- lane 1 no treatment
- lane 2 O-glycosidase / neuraminidase treatment
- lane 3 PNGase F treatment
- lane 4 O-glycosidase / neuraminidase / PNGase F treatment.
- the molecular weights of the enzymes used for sugar chain treatment are 147 kDa for O-glycosidase, 43 kDa for neuraminidase, and 36 kDa for PNGase F.
- the optimum pH of the purified enzyme PH stability of the purified enzyme.
- Optimum temperature for purified enzyme Temperature stability of the purified enzyme.
- a purified enzyme (wild-type enzyme) derived from MM13-F2171 strain was reacted with lactose as a substrate.
- the degree of polymerization of GOS when the amount of galactooligosaccharide (GOS) produced was about 50% was compared with known ⁇ -galactosidase (top).
- the ratio of linear oligosaccharide and branched oligosaccharide in the trisaccharide was compared with known ⁇ -galactosidase (lower panel).
- Measurement results of molecular weight of mutant enzyme derived from Cryptococcus terrestris M2 strain and mutant enzyme derived from Cryptococcus terrestris M6 strain SDS-PAGE. Lanes 1 to 4 show the results of the mutant enzyme derived from the M2 strain.
- M molecular weight marker
- lane 1 no treatment
- lane 2 O-glycosidase / neuraminidase treatment
- lane 3 PNGase F treatment
- lane 4 O-glycosidase / neuraminidase / PNGase F treatment
- Lanes 5 to 8 show the results of the mutant enzyme derived from the M6 strain. Lane 5: no treatment
- lane 6 O-glycosidase / neuraminidase treatment
- lane 7 PNGase F treatment
- lane 8 O-glycosidase / neuraminidase / PNGase F treatment.
- Oligosaccharide-producing ability of purified enzyme (mutant enzyme 3).
- lactose as a substrate, purified enzyme derived from Cryptococcus terrestris M2 strain (mutant enzyme 1) and purified enzyme derived from Cryptococcus terrestris M6 strain (mutant enzyme 3) were reacted.
- isolated is used herein interchangeably with “purified”.
- isolated is used to distinguish it from its natural state, ie, one that exists in nature. An artificial operation of isolation results in an “isolated state” that is different from the natural state. What has been isolated is clearly and critically different from the natural product itself.
- the purity of the isolated enzyme is not particularly limited. However, if application to a use requiring high purity is planned, it is preferable that the purity of the isolated enzyme is high.
- ⁇ -galactosidase generally exhibits lactose-degrading activity (activity that degrades lactose by acting on ⁇ -1,4 bonds) and galactosyl transfer activity (activity that transfers galactose). Therefore, “ ⁇ -galactosidase activity” in the present invention includes these two activities.
- the lactose decomposition activity can be measured by the activity measurement method (lactose method) shown in the Examples.
- the galactosyl transfer activity can be evaluated by the method for measuring the degree of polymerization of oligosaccharide-producing ability shown in the Examples.
- the first aspect of the present invention provides ⁇ -galactosidase and its producing bacterium.
- wild-type enzyme highly useful ⁇ -galactosidase
- wild-type highly useful ⁇ -galactosidase
- mutant enzymes 1, 2, and 3 three types of ⁇ -galactosidase produced by the mutant strain were identified and their amino acid sequences were identified.
- ⁇ -galactosidase were part of the full-length amino acid sequence (SEQ ID NO: 1) deduced from the gene sequence of the wild-type enzyme. Specifically, the N-terminal 130 amino acid residue of the full length amino acid sequence (SEQ ID NO: 1) is deleted (referred to as “mutant enzyme 1” for convenience of explanation), and the N of the full length amino acid sequence (SEQ ID NO: 1). Those lacking 136 amino acid residues on the terminal side (referred to as “mutant enzyme 2” for convenience of explanation), those lacking 141 amino acid residues on the N-terminal side of the full-length amino acid sequence (SEQ ID NO: 1) (for convenience of explanation, Called "mutant enzyme 3").
- the ⁇ -galactosidase of the present invention includes any one of the amino acid sequences of SEQ ID NOs: 1 to 4 or an amino acid sequence equivalent to the amino acid sequence.
- the amino acid sequence of SEQ ID NO: 2 corresponds to the amino acid sequence of mutant enzyme 1
- the amino acid sequence of SEQ ID NO: 3 corresponds to the amino acid sequence of mutant enzyme 2
- the amino acid sequence of SEQ ID NO: 4 is the amino acid sequence of mutant enzyme 3. It corresponds to.
- the “equivalent amino acid sequence” here is partially different from the standard sequence (the amino acid sequence of any one of SEQ ID NOs: 1 to 4), but the difference is the function of the protein (here, ⁇ -galactosidase activity).
- an enzyme having a polypeptide chain consisting of an equivalent amino acid sequence is ⁇ -galactosidase.
- the degree of activity is not particularly limited as long as it can function as ⁇ -galactosidase.
- the enzyme has a polypeptide chain having a standard sequence or higher than that of the enzyme.
- the equivalent amino acid sequence consists of an amino acid sequence that does not exceed the length of the sequence of SEQ ID NO: 1.
- “Partial difference in amino acid sequence” typically means deletion or substitution of 1 to several amino acids (upper limit is 3, 5, 7, 10) constituting an amino acid sequence, Alternatively, it means that a mutation (change) has occurred in the amino acid sequence due to addition, insertion, or a combination of 1 to several amino acids (upper limit is 3, 5, 7, 10), for example. Differences in the amino acid sequence here are permissible as long as ⁇ -galactosidase is retained (there may be some variation in activity). As long as this condition is satisfied, the positions where the amino acid sequences are different are not particularly limited, and differences may occur at a plurality of positions.
- the “plurality” herein is, for example, a number corresponding to less than about 20% of all amino acids, preferably a number corresponding to less than about 15%, more preferably a number corresponding to less than about 10%, Even more preferred is a number corresponding to less than about 5%, most preferred a number corresponding to less than about 1%. That is, the equivalent protein has a reference sequence of, for example, about 80% or more, preferably about 85% or more, more preferably about 90% or more, more preferably about 95% or more, still more preferably about 97% or more, and most preferably Have about 99% or more identity. The difference in amino acid sequence may occur at a plurality of positions.
- equivalent amino acid sequences are obtained by causing conservative amino acid substitutions at amino acid residues that are not essential for ⁇ -galactosidase.
- conservative amino acid substitution refers to substitution of a certain amino acid residue with an amino acid residue having a side chain having the same properties.
- a basic side chain eg lysine, arginine, histidine
- an acidic side chain eg aspartic acid, glutamic acid
- an uncharged polar side chain eg glycine, asparagine, glutamine, serine, threonine, tyrosine
- Cysteine eg alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, tryptophan
- ⁇ -branched side chains eg threonine, valine, isoleucine
- aromatic side chains eg tyrosine, phenylalanine, Like tryptophan and histidine.
- a conservative amino acid substitution is preferably a substitution between amino acid residues within the same family.
- the identity (%) of two amino acid sequences or two nucleic acid sequences can be determined, for example, by the following procedure.
- two sequences are aligned for optimal comparison (eg, a gap may be introduced into the first sequence to optimize alignment with the second sequence).
- a molecule amino acid residue or nucleotide
- Gapped BLAST described in Altschul et al. (1997) Amino Acids Research 25 (17): 3389-3402 can be used.
- the default parameters of the corresponding programs eg, XBLAST and NBLAST
- gap weight 12, 10, 8, 6, or 4
- the enzyme may be part of a larger protein (eg, a fusion protein).
- a larger protein eg, a fusion protein
- sequences added in the fusion protein include sequences useful for purification, such as multiple histidine residues, and additional sequences that ensure stability during recombinant production.
- the present enzyme having the above amino acid sequence can be easily prepared by a genetic engineering technique. For example, it can be prepared by transforming a suitable host cell (for example, E. coli) with DNA encoding the present enzyme and recovering the protein expressed in the transformant. The recovered protein is appropriately purified according to the purpose. Thus, if this enzyme is obtained as a recombinant protein, various modifications are possible. For example, if a DNA encoding this enzyme and another appropriate DNA are inserted into the same vector and a recombinant protein is produced using the vector, the peptide consists of a recombinant protein linked to any peptide or protein. This enzyme can be obtained.
- a suitable host cell for example, E. coli
- modification may be performed so that addition of sugar chain and / or lipid, or processing of N-terminal or C-terminal may occur.
- modification as described above, extraction of recombinant protein, simplification of purification, addition of biological function, and the like are possible.
- this enzyme can also be characterized by the following enzyme chemical properties (1) to (3).
- This enzyme has lactose-degrading activity and galactosyl transfer activity, and is ⁇ -1,4 bond rather than ⁇ -1,6 bond, ⁇ -1,3 bond or ⁇ -1,2 bond transfer activity
- the translocation activity is superior. That is, this enzyme is excellent in the transfer activity to ⁇ -1,4 bond. Therefore, according to the present enzyme, a product in which the transferred sugar is bound by ⁇ -1,4 bonds can be efficiently obtained.
- this enzyme is allowed to act on lactose (substrate), trisaccharide oligosaccharides rich in linear oligosaccharides can be obtained.
- a linear oligosaccharide is an oligosaccharide having a structure in which constituent monosaccharides are linked by ⁇ -1,4 glycoside bonds, and is a branched oligosaccharide (having ⁇ -1,6 glycoside bonds, ⁇ -1,2 glycoside bonds, etc.) And contrast.
- a galactooligosaccharide is represented by Gal- (Gal) n-Glc (n is about 0 to 5) (Gal: galactose residue, Glc: glucose residue).
- Glc galactose residue
- lactose does not correspond to a galactooligosaccharide. Therefore, in this specification, “galactooligosaccharide (GOS)” means a galactooligosaccharide having a degree of polymerization of 2 or more sugars, excluding lactose.
- This enzyme is excellent in transglycosylation activity. Under the reaction conditions (examination of oligosaccharide production ability) described in the examples below, when this enzyme is allowed to act using lactose as a substrate, it varies depending on the reaction temperature conditions, but 45% of the total sugar after the reaction. The galactooligosaccharide occupies the above (50% or more when the reaction is performed near the optimum temperature).
- the optimal temperature of this enzyme is 70 ° C.
- Such a high optimum temperature is advantageous as an enzyme for producing oligosaccharides.
- the treatment temperature reaction temperature
- the treatment temperature can be set high.
- Increasing the treatment temperature increases the solubility of the substrate and enables high concentration preparation.
- the concentration cost can be reduced.
- the risk of contamination can be reduced.
- the optimum temperature can be evaluated by a measurement method using an acetate buffer (pH 6.0) and lactose as a substrate.
- Both the wild-type enzyme and the mutant enzymes 1 to 3 corresponding to this enzyme contain sugar chains. After removing the N-type sugar chain and the O-type sugar chain, the molecular weight is measured by SDS-PAGE. They were kDa (wild type enzyme), 64 kDa (mutant enzyme 1), 61 kDa (mutant enzyme 2), and 61 kDa (mutant enzyme 3). Based on this fact, one embodiment of the present enzyme has a molecular weight (according to SDS-PAGE) of 104 kDa when no sugar chain is contained. In another embodiment, the molecular weight is 64 kDa. In yet another embodiment, the molecular weight is 61 kDa.
- the molecular weight (according to SDS-PAGE) when the sugar chain is not removed is 120 kDa (wild type enzyme), 71 kDa (mutant enzyme 1), 66 kDa mutant enzyme 2), 66 kDa (mutant) Enzyme 3).
- the enzyme can be further characterized by the following enzymological properties (4) to (6).
- (4) Optimum pH The optimum pH is 4-5.
- the optimum pH is, for example, 0.1 M glycine buffer in the pH range of 2 to 3, 0.1 M citrate buffer in the pH range of 3 to 6, 0.1 M acetate buffer in the pH range of 5 to 6, pH 7 to 8 In the pH range of 0.1M phosphate buffer, and in the pH range of 9 to 10, it is determined based on the results measured in 0.1M sodium carbonate buffer.
- pH stability One embodiment of the enzyme exhibits stable activity in the pH range of pH 2-8, and another embodiment of the enzyme exhibits stable activity in the pH range of pH 2-9. That is, if the pH of the enzyme solution used for the treatment is within this range, it shows 80% or more of the maximum activity after treatment at 40 ° C. for 30 minutes.
- the pH stability is, for example, 0.1 M glycine buffer in the pH range of pH 2 to 3, 0.1 M citrate buffer in the pH range of pH 3 to 6, 0.1 M acetate buffer in the pH range of pH 5 to 6, pH 7 to 8 In the pH range of 0.1M phosphate buffer, and in the pH range of 9 to 10, it is determined based on the results measured in 0.1M sodium carbonate buffer.
- the enzyme of one embodiment maintains an activity of 80% or more in an acetate buffer (pH 6.0) even when treated at 30 ° C. to 60 ° C. for 30 minutes.
- Another embodiment of the enzyme maintains an activity of 80% or more in an acetate buffer (pH 6.0) even when treated at 30 ° C. to 65 ° C. for 30 minutes.
- the enzyme is preferably ⁇ -galactosidase derived from Cryptococcus terrestris.
- ⁇ -galactosidase derived from Cryptococcus terrestris means ⁇ -galactosidase produced by a microorganism (either wild or mutant) classified as Cryptococcus terrestris, or Cryptococcus cerevisiae It means ⁇ -galactosidase obtained by genetic engineering techniques using the ⁇ -galactosidase gene of Terrestris (which may be a wild strain or a mutant strain).
- a recombinant produced by a host microorganism into which a ⁇ -galactosidase gene (or a gene modified from the gene) obtained from Cryptococcus terrestris is also a “ ⁇ -galactosidase derived from Cryptococcus terrestris”.
- the Cryptococcus terrestris from which the enzyme is derived, is referred to as the producing microorganism of the enzyme for convenience of explanation.
- the present inventors succeeded in isolating and purifying ⁇ -galactosidase having the above properties from Cryptococcus terrestris MM13-F2171 strain and its mutant strains (M2 strain, M6 strain).
- the Cryptococcus terrestris MM13-F2171 and M2 strains are deposited with the prescribed depository as follows and are readily available.
- the gene of the present invention comprises DNA encoding any amino acid sequence of SEQ ID NOs: 1-4.
- Specific examples of the embodiment include a cDNA comprising the nucleotide sequence of SEQ ID NO: 5 (encoding the amino acid sequence of SEQ ID NO: 1), a cDNA comprising the nucleotide sequence of SEQ ID NO: 6 (encoding the amino acid sequence of SEQ ID NO: 2), a sequence CDNA consisting of the base sequence of No. 7 (encoding the amino acid sequence of SEQ ID No.
- genomic DNA consisting of the nucleotide sequence of SEQ ID NO: 16.
- the genomic DNA corresponds to the cDNA of SEQ ID NO: 5.
- the gene encoding this enzyme is typically used for the preparation of this enzyme. According to a genetic engineering preparation method using a gene encoding this enzyme, it is possible to obtain the enzyme in a more homogeneous state. This method can also be said to be a suitable method when preparing a large amount of the present enzyme.
- the use of the gene encoding this enzyme is not limited to the preparation of this enzyme.
- the gene can also be used as an experimental tool for elucidating the mechanism of action of the enzyme or as a tool for designing or preparing a mutant (modified) of the enzyme.
- the “gene encoding the enzyme” refers to a nucleic acid from which the enzyme is obtained when it is expressed, not to mention a nucleic acid having a base sequence corresponding to the amino acid sequence of the enzyme. Also included are nucleic acids obtained by adding sequences that do not encode amino acid sequences to such nucleic acids. Codon degeneracy is also considered.
- the gene of the present invention can be obtained by referring to sequence information disclosed in this specification or the attached sequence listing, using standard genetic engineering techniques, molecular biological techniques, biochemical techniques, chemical synthesis, PCR methods (for example, overexpression). Wrap PCR) or a combination thereof can be prepared in an isolated state.
- DNA DNA encoding a protein having a base sequence equivalent to a reference base sequence (sequence of any of SEQ ID NOs: 5 to 8 and 16) and having ⁇ -galactosidase activity (hereinafter referred to as “DNA”) , Also referred to as “equivalent DNA”).
- the “equivalent base sequence” here is partially different from the nucleic acid shown in the reference base sequence, but due to the difference, the function of the protein encoded by it ( ⁇ -galactosidase activity in this case) has a substantial effect.
- a specific example of equivalent DNA is DNA that hybridizes under stringent conditions to a base sequence complementary to a reference base sequence.
- the “stringent conditions” here are conditions under which so-called specific hybrids are formed and non-specific hybrids are not formed.
- Such stringent conditions are known to those skilled in the art, such as Molecular Cloning (Third Edition, Cold Spring Harbor Laboratory Press, New York) and Current protocols in molecular biology (edited by Frederick M. Ausubel et al., 1987) Can be set with reference to.
- hybridization solution 50% formamide, 10 ⁇ SSC (0.15M NaCl, 15 mM sodium citrate, pH 7.0), 5 ⁇ Denhardt solution, 1% SDS, 10% dextran sulfate, 10 ⁇ g / ml denaturation
- the conditions include incubation at about 50 ° C. using salmon sperm DNA, 50 mM phosphate buffer (pH 7.5), and then washing at about 65 ° C. using 0.1 ⁇ SSC, 0.1% SDS.
- Further preferable stringent conditions include, for example, 50% formamide, 5 ⁇ SSC (0.15M NaCl, 15 mM sodium citrate, pH 7.0), 1 ⁇ Denhardt solution, 1% SDS, 10% dextran sulfate, 10 ⁇ g / ml as a hybridization solution. Of denatured salmon sperm DNA, 50 mM phosphate buffer (pH 7.5)).
- equivalent DNA it consists of a base sequence including substitution, deletion, insertion, addition, or inversion of one or more (preferably 1 to several) bases with respect to a base base sequence
- Examples include DNA encoding a protein having ⁇ -galactosidase activity. Base substitution or deletion may occur at a plurality of sites.
- the term “plurality” as used herein refers to, for example, 2 to 40 bases, preferably 2 to 20 bases, more preferably 2 to 10 bases, although it varies depending on the position and type of amino acid residues in the three-dimensional structure of the protein encoded by the DNA. It is.
- the equivalent nucleic acid is, for example, 60% or more, preferably 70% or more, more preferably 80% or more, still more preferably 85% or more, still more preferably about 90% or more, even more preferably, relative to the base sequence serving as a reference. Has an identity of 95% or more, most preferably 99% or more.
- Such equivalent DNAs include, for example, restriction enzyme treatment, treatment with exonuclease and DNA ligase, position-directed mutagenesis (MolecularMCloning, Third Edition, Chapter 13, Cold Spring Harbor Laboratory Press, New York) Includes substitutions, deletions, insertions, additions, and / or inversions of bases using mutation introduction methods (Molecular Cloning, ingThird Edition, Chapterhap13, Cold Spring Harbor Laboratory Press, New York) Thus, it can obtain by modifying DNA which has a base sequence used as a standard.
- the equivalent DNA can also be obtained by other methods such as ultraviolet irradiation.
- Still another example of equivalent DNA is DNA in which a base difference as described above is recognized due to a polymorphism represented by SNP (single nucleotide polymorphism).
- Another aspect of the present invention relates to a nucleic acid having a base sequence complementary to the base sequence of a gene encoding the enzyme of the present invention.
- Yet another embodiment of the present invention provides at least about 60%, 70%, 80%, 85%, 90%, 95% of the base sequence of the gene encoding the enzyme of the present invention or a base sequence complementary thereto. %, 98%, 99% or 99.9% nucleic acids having the same base sequence are provided.
- Still another aspect of the present invention relates to a recombinant DNA containing the gene of the present invention (gene encoding the enzyme).
- the recombinant DNA of the present invention is provided, for example, in the form of a vector.
- vector refers to a nucleic acid molecule capable of transporting a nucleic acid inserted therein into a target such as a cell.
- An appropriate vector is selected according to the purpose of use (cloning, protein expression) and in consideration of the type of host cell.
- Examples of vectors using insect cells as hosts include pAc and pVL, and examples of vectors using mammalian cells as hosts include pCDM8 and pMT2PC.
- the vector of the present invention is preferably an expression vector.
- “Expression vector” refers to a vector capable of introducing a nucleic acid inserted therein into a target cell (host cell) and allowing expression in the cell.
- Expression vectors usually contain a promoter sequence necessary for the expression of the inserted nucleic acid, an enhancer sequence that promotes expression, and the like.
- An expression vector containing a selectable marker can also be used. When such an expression vector is used, the presence / absence (and extent) of introduction of the expression vector can be confirmed using a selection marker.
- Insertion of DNA into a vector, insertion of a selectable marker gene (if necessary), insertion of a promoter (if necessary), etc. are performed using standard recombinant DNA techniques (eg, Molecular Cloning, Third Edition, 1.84, Cold Spring Harbor Laboratory Can be performed using a known method using a restriction enzyme and DNA ligase), which can be referred to Press, “New York”.
- the present invention further relates to a host cell (transformant) into which the recombinant DNA of the present invention (including the gene of the present invention) has been introduced.
- the recombinant DNA of the present invention exists as an exogenous molecule.
- the transformant of the present invention is preferably prepared by transfection or transformation using the vector of the present invention. For transfection and transformation, calcium phosphate coprecipitation method, electroporation (Potter, H. et al., Proc. Natl. Acad. Sci. USA 81, 7161-7165 (1984)), lipofection (Felgner, PL et al. , Proc. Natl. Acad. Sci.
- the host cell is not particularly limited as long as the present enzyme is expressed.
- Yeasts such as Saccharomyces, Kluyveromyces, Candida, Torula, Torulopsis, Pichia, Schizosaccharomyces, etc., Aspergillus genus such as Aspergillus oryzae, Aspergillus niger, etc. .
- the second aspect of the present invention provides a method for producing ⁇ -galactosidase.
- a step of culturing Cryptococcus terrestris (step (1)) and a step of recovering ⁇ -galactosidase from the culture medium and / or the cells after the culture (step (2)) are performed.
- MM13-F2171 strain or a mutant thereof for example, Cryptococcus terrestris APC-6431 (M2 strain) or a further mutant of the strain
- the culture conditions and culture method are not particularly limited as long as the present enzyme is produced.
- the culture method may be either liquid culture or solid culture, but preferably liquid culture is used. Taking liquid culture as an example, the culture conditions will be described.
- the medium is not particularly limited as long as the microorganism to be used can grow.
- carbon sources such as glucose, sucrose, gentiobiose, soluble starch, glycerin, dextrin, molasses, organic acids, ammonium sulfate, ammonium carbonate, ammonium phosphate, ammonium acetate, or peptone, yeast extract, corn steep liquor, casein
- Nitrogen sources such as hydrolysates, bran and meat extracts, and further added with inorganic salts such as potassium salts, magnesium salts, sodium salts, phosphates, manganese salts, iron salts and zinc salts can be used.
- vitamins, amino acids and the like may be added to the medium.
- the pH of the medium is adjusted to, for example, about 3 to 8, preferably about 4 to 7, and the culture temperature is usually about 20 to 40 ° C., preferably about 25 to 35 ° C. for 1 to 10 days, preferably 3 to Incubate under aerobic conditions for about 6 days.
- the culture method for example, a shaking culture method or an aerobic deep culture method using a jar fermenter can be used.
- the target enzyme is recovered from the culture broth or cells (step (2)).
- the culture supernatant is filtered, centrifuged, etc. to remove insolubles, concentrated by ultrafiltration membrane, salting out such as ammonium sulfate precipitation, dialysis, ion exchange resin, etc.
- the present enzyme can be obtained by performing separation and purification by appropriately combining various types of chromatography.
- the bacterial cells are crushed by pressure treatment, ultrasonic treatment, etc., and then separated and purified in the same manner as described above to obtain the target protein.
- recovering a microbial cell from a culture solution previously by filtration, a centrifugation process, etc. you may perform the said series of processes (crushing, isolation
- ⁇ -galactosidase is produced using the above transformant.
- the above-mentioned transformant is cultured under the condition that a protein encoded by the gene introduced therein is produced (step (i)).
- Culture conditions for transformants are known for various vector host systems, and those skilled in the art can easily set appropriate culture conditions.
- the produced protein ie ⁇ -galactosidase
- step (ii) Recovery and subsequent purification may be performed in the same manner as in the above embodiment.
- the degree of purification of ⁇ -galactosidase is not particularly limited.
- the final form may be liquid or solid (including powder).
- the purified enzyme obtained as described above can be provided by pulverization, for example, by freeze drying, vacuum drying or spray drying. At that time, the purified enzyme may be dissolved in advance in an acetate buffer, phosphate buffer, triethanolamine buffer, Tris-HCl buffer or GOOD buffer.
- acetate buffer, phosphate buffer, and triethanolamine buffer can be used.
- PIPES, MES, or MOPS is mentioned as a GOOD buffer here.
- the enzyme is provided, for example, in the form of an enzyme agent.
- the present enzyme agent may contain excipients, buffers, suspending agents, stabilizers, preservatives, preservatives, physiological saline and the like.
- the degree of purification of the enzyme as an active ingredient is not particularly limited. That is, it may be a crude enzyme or a purified enzyme.
- the excipient lactose, sorbitol, D-mannitol, maltodextrin, sucrose, sodium chloride and the like can be used. Phosphate, citrate, acetate, etc. can be used as the buffer.
- propylene glycol, ascorbic acid or the like can be used.
- preservatives phenol, benzalkonium chloride, benzyl alcohol, chlorobutanol, methylparaben, and the like can be used.
- preservatives benzalkonium chloride, paraoxybenzoic acid, chlorobutanol and the like can be used.
- a further aspect of the present invention provides use of the enzyme or the enzyme agent.
- Examples of applications are the production of galactooligosaccharides, the production of low lactose milk, or the manufacture of medicines and supplements for patients with lactose intolerance.
- Galactooligosaccharides are used as, for example, intestinal bifidobacterial growth factors.
- the present enzyme or the present enzyme agent is particularly useful in the production of galactooligosaccharide.
- galactooligosaccharides rich in linear oligosaccharides can be produced using lactose as a raw material.
- lactose as a raw material.
- 75 U to 5000 U of this enzyme is added to 1 L of 30% to 65% lactose solution (pH 5.0) dissolved in advance, and then 30 ° C. to 75 ° C. for 15 hours to React for 50 hours to produce galactooligosaccharides. Since this enzyme has a high optimum temperature, the treatment temperature (reaction temperature) is high (for example, 40 ° C.
- the raw material (substrate) for producing an oligosaccharide using the present enzyme or the present enzyme agent is preferably lactose, but is not limited thereto.
- a disaccharide, oligosaccharide or polysaccharide having at least one of ⁇ -1,3 bond, ⁇ -1,4 bond and ⁇ -1,6 bond can be used as a raw material.
- Cryptococcus terrestris MM13-F2171 strain was deposited under the name of Cryptococcus terrestris MM13-F2171 on December 10, 2015 at the National Institute of Technology and Evaluation Microorganisms, and assigned the accession number NITE BP-02177 It was.
- the obtained enzyme activity fraction was subjected to a hydrophobic column HiTrap Phenyl HP (GE Healthcare Bioscience) equilibrated with 20 mM acetate buffer pH 6.0 containing 1.8 M ammonium sulfate.
- the adsorbed components were eluted with a gradient of 20 mM acetate buffer pH 6.0 to confirm the enzyme activity.
- Fractions with confirmed enzyme activity were collected and dialyzed against 20 mM acetate buffer pH 6.0 containing 0.2 M NaCl.
- the obtained enzyme activity fraction was subjected to a gel filtration column HiLoad Superdex 200 prep grade (GE Healthcare Bioscience) equilibrated with 20 mM acetate buffer pH 6.0 containing 0.2 M NaCl, and the fraction showing enzyme activity was obtained. It was collected.
- the molecular weight was about 266 kDa. When considered together with the results of SDS-PAGE (below), it seems to form a dimer.
- the molecular weight of the wild-type enzyme was measured by SDS-PAGE.
- the wild-type enzyme is denatured (in a denaturing buffer, boiling water bath, 10 minutes), and then O-type sugar chain removal treatment (simultaneous treatment of O-glycosidase and neuraminidase) (O-Glycosidase & Neuraminidase Bundle, New England Biolabs) )) and / or N-type sugar chain removal treatment (treatment with PNGase F (New England Biolabs)).
- O-type sugar chain removal treatment Simultaneous treatment of O-glycosidase and neuraminidase
- PNGase F New England Biolabs
- the molecular weight When untreated (lane 1), the molecular weight is 120 kDa, when O-type sugar chain is removed (lane 2), the molecular weight is 106 kDa, when N-type sugar chain is removed (lane 3), the molecular weight is 104 ⁇ kDa, When the O-type sugar chain and the N-type sugar chain were removed (lane 4), the molecular weight was 104 kDa.
- cDNA was synthesized using SMARTer RACE 5 ′ / 3 ′ kit (TaKaRa), and 5 ′ and 3 ′ RACE PCR was performed.
- GATTACGCCAAGCTTgcaaagatcccgatctggtacgcctg (SEQ ID NO: 14) was used as the GSP primer for 5′RACE
- GATTACGCCAAGCTTttcctgtttggctgggcgaccgcc SEQ ID NO: 15
- the base sequence of the obtained RACE PCR product was analyzed, and the full-length cDNA sequence (SEQ ID NO: 5) was determined.
- the deduced amino acid sequence encoded by the full-length cDNA sequence is shown in SEQ ID NO: 1.
- genomic DNA sequence (SEQ ID NO: 16) encoding ⁇ -galactosidase produced by Cryptococcus terrestris MM13-F2171 was successfully determined.
- oligosaccharide production ability 1 (1) Method The ability of the purified enzyme to produce oligosaccharides was examined. 1 U of wild-type enzyme was added to 53% lactose solution preheated to the reaction temperature, and reacted at each temperature for 24 hours. Analysis by HPLC (under the following conditions), the composition of the sugar contained in the solution after the reaction was examined. The transfer activity can be evaluated from the measurement result of the sugar composition.
- the ratio (%) of the degree of polymerization in GOS was calculated.
- the results of the degree of polymerization (typical results) when a purified enzyme (wild-type enzyme) is used are shown in the upper part of FIG. It can be seen that the wild-type enzyme (Cryptococcus terrestris) is excellent in GOS production ability, and particularly efficiently produces oligosaccharides of 3 or more sugars.
- the ratio (%) of the linear oligosaccharide and the branched oligosaccharide in the generated trisaccharide was calculated, and the ratio of the branched chain (branching degree) was compared with each enzyme.
- the result of the degree of branching when a purified enzyme (wild-type enzyme) is used is shown in the lower part of FIG. It can be seen that the wild-type enzyme (Cryptococcus terrestris) mainly produces linear oligosaccharides. That is, it has been revealed that it has a translocation activity specific to ⁇ -1,4 glycosidic bonds, and that it is difficult to transfer sugars especially to form ⁇ -1,6 glycosidic bonds.
- mutant strain 6 acquisition of ⁇ -galactosidase produced by mutant strain, identification of amino acid sequence, measurement of molecular weight
- M2 strain and M6 strain Two types of mutant strains (M2 strain and M6 strain) were obtained from Cryptococcus terrestris MM13-F2171 strain by UV treatment. The ⁇ -galactosidase produced by these mutant strains is as described in 1. above. The product was purified by the same procedure as (2). Both the M2 and M6 strains have the ability to produce mutant enzymes 1 to 3, but the M2 strain has a particularly high ability to produce mutant enzyme 1, and the M6 strain has the ability to produce mutant enzymes 2 and 3. Is particularly expensive.
- the Cryptococcus terrestris M2 strain was deposited with the Patent Microorganism Depositary, National Institute of Technology and Evaluation on December 10, 2015, under the name Cryptococcus terrestris APC-6431, and was assigned the deposit number NITE BP-02178. .
- the amino acid sequences of the obtained purified enzymes namely, the enzyme derived from mutant M2 (mutant enzyme 1) and two kinds of enzymes derived from mutant M6 (mutant enzyme 2, mutant enzyme 3) were determined.
- the N-terminal amino acid sequences of mutant enzymes 1 to 3 were determined using a protein sequencer (PPSQ-31A Takashimazu Seisakusho).
- PPSQ-31A Takashimazu Seisakusho a protein sequencer
- a nucleotide sequence corresponding to the N-terminal amino acid sequence of each mutant enzyme was found from the cDNA sequence of the wild-type enzyme (SEQ ID NO: 5), and the cDNA sequence encoding each mutant enzyme was identified.
- the amino acid sequence of the mutant enzyme 1 corresponds to a deletion of the 130 amino acid residues on the N-terminal side of the full-length amino acid sequence (SEQ ID NO: 1) deduced from the cDNA sequence of the wild-type enzyme (SEQ ID NO: 5). .
- the amino acid sequence of mutant enzyme 2 corresponds to the deletion of the 136 amino acid residues on the N-terminal side of the full-length amino acid sequence (SEQ ID NO: 1).
- the molecular weight of each mutant enzyme was measured by SDS-PAGE.
- the operation and conditions of the sugar chain treatment are According to (2).
- the result of SDS-PAGE is shown in FIG.
- the molecular weight of each mutant enzyme was as follows: . From the results of SDS-PAGE, it can be confirmed that the M2 strain produces not only the mutant enzyme 1 but also the mutant enzyme 2 and the mutant enzyme 3.
- Mutant enzyme 1 (lanes 1 and 5): 71 kDa Mutant enzyme 2 (lanes 1 and 5): 66 kDa Mutant enzyme 3 (lanes 1 and 5): 66 kDa ⁇ When O-type sugar chain is removed> Mutant enzyme 1 (lanes 2 and 6): 65 kDa Mutant enzyme 2 (lanes 2 and 6): 63 kDa Mutant enzyme 3 (lanes 2 and 6): 62 kDa ⁇ When N-type sugar chain is removed> Mutant enzyme 1 (lanes 3 and 7): 64 kDa Mutant enzyme 2 (lanes 3 and 7): 61 kDa Mutant enzyme 3 (lanes 3 and 7): 61 kDa ⁇ When O-type and N-type sugar chains are removed> Mutant enzyme 1 (lanes 4 and 8): 64 kDa Mutant enzyme 2 (lanes 4 and 8): 61 kDa Mutant enzyme 3 (lanes 4 and 8): 61 kDa Mutant enzyme 3
- the ratio (%) of the degree of polymerization in GOS was calculated.
- the results (typical results) in the case of using the purified enzyme derived from the M2 strain (mutant enzyme 1) and the purified enzyme derived from the M6 strain (mutant enzyme 3) are shown in the upper part of FIG. It can be seen that the mutant enzyme is excellent in GOS production ability, and particularly efficiently produces oligosaccharides having 3 or more sugars. Moreover, it turns out that there is no difference in the GOS production ability of a wild-type enzyme and a mutant enzyme.
- the ratio (%) of the linear oligosaccharide and the branched oligosaccharide in the generated trisaccharide was calculated, and the ratio of the branched chain (branch degree) was compared with each enzyme (lower part of FIG. 10).
- the mutant enzyme (Cryptococcus terrestris) mainly produces linear oligosaccharides. That is, it has been revealed that it has a translocation activity specific to ⁇ -1,4 glycosidic bonds, and that it is difficult to transfer sugars especially to form ⁇ -1,6 glycosidic bonds.
- Mutant enzyme 2 is an enzyme that is 6 amino acid residues shorter on the N-terminal side than mutant enzyme 1 and 5 amino acid residues longer on the N-terminal side than mutant enzyme 3. Since it is clear from the above results that the amino acid sequence of the N-terminal region does not affect the properties of the enzyme, it is presumed that the mutant enzyme 2 also has the same properties as the mutant enzymes 1, 3.
- mutant enzyme 1 and mutant enzyme 3 Examination of properties of mutant enzyme 1 and mutant enzyme 3 The properties of mutant enzyme 1 and mutant enzyme 3 were confirmed using purified enzyme (see 6. above). The experimental method was the same as in the case of the wild type enzyme (see 4. above).
- (1) Optimum pH and pH stability The measurement results regarding the optimum pH are shown in FIG. 11 (mutant enzyme 1) and FIG. 12 (mutant enzyme 3). The optimum pH of mutant enzyme 1 and mutant enzyme 3 was 4-5. On the other hand, the measurement results regarding pH stability are shown in FIG. 13 (mutant enzyme 1) and FIG. 14 (mutant enzyme 3). Mutant enzyme 1 and mutant enzyme 3 both showed stable activity in the pH range of pH 2-9.
- the present invention provides a novel ⁇ -galactosidase particularly useful for the production of oligosaccharides.
- the ⁇ -galactosidase of the present invention is useful, for example, for the purpose of producing a galactooligosaccharide having a high linear oligosaccharide content.
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Abstract
Description
以下の発明は上記の成果に基づき完成されたものである。
[1]配列番号1~4のいずれかのアミノ酸配列、又は該アミノ酸配列と80%以上同一のアミノ酸配列を含む、β-ガラクトシダーゼ。
[2]アミノ酸配列が、配列番号1~4のいずれかのアミノ酸配列と85%以上同一のアミノ酸配列である、[1]に記載のβ-ガラクトシダーゼ。
[3]アミノ酸配列が、配列番号1~4のいずれかのアミノ酸配列と90%以上同一のアミノ酸配列である、[1]に記載のβ-ガラクトシダーゼ。
[4]配列番号1の配列の長さを超えない長さのアミノ酸配列からなる、[1]~[3]のいずれか一項に記載のβ-ガラクトシダーゼ。
[5]下記の酵素化学的性質を有するβ-ガラクトシダーゼ、
(1)作用:ラクトース分解活性とガラクトシル転移活性を有し、β-1,6結合、β-1,3結合又はβ-1,2結合への転移活性よりもβ-1,4結合への転移活性が優位である、
(2)至適温度:70℃、
(3)糖鎖を含まない場合の分子量:約104 kDa、約64 kDa、又は約61 kDa(SDS-PAGEによる)。
[6]下記の酵素化学的性質を更に有する、[5]に記載のβ-ガラクトシダーゼ、
(4)至適pH:4~5、
(5)pH安定性:pH2~8の範囲で安定(40℃、30分間)、
(6)温度安定性:30℃~60℃の範囲で安定(pH6.0、30分間)。
[7]下記の酵素化学的性質を更に有する、[5]に記載のβ-ガラクトシダーゼ、
(4)至適pH:4~5、
(5)pH安定性:pH2~9の範囲で安定(40℃、30分間)、
(6)温度安定性:30℃~65℃の範囲で安定(pH6.0、30分間)。
[8]クリプトコッカス・テレストリス由来である、[1]~[7]のいずれか一項に記載のβ-ガラクトシダーゼ。
[9]クリプトコッカス・テレストリスがMM13-F2171株(受託番号:NITE BP-02177)又はAPC-6431株(受託番号:NITE BP-02178)である、[8]に記載のβ-ガラクトシダーゼ。
[10][1]~[9]のいずれか一項に記載のβ-ガラクトシダーゼを有効成分とする酵素剤。
[11]以下の(a)~(c)からなる群より選択されるいずれかのDNAからなるβ-ガラクトシダーゼ遺伝子:
(a)配列番号1~4のいずれかのアミノ酸配列をコードするDNA;
(b)配列番号5~8、16いずれかの塩基配列からなるDNA;
(c)配列番号5~8、16のいずれかの塩基配列と等価な塩基配列を有し、且つβ-ガラクトシダーゼ活性を有するタンパク質をコードするDNA。
[12][11]に記載のβ-ガラクトシダーゼ遺伝子を含む組換えDNA。
[13][12]に記載の組換えDNAを保有する微生物。
[14]以下のステップ(1)及び(2)を含む、β-ガラクトシダーゼの製造法:
(1)クリプトコッカス・テレストリスを培養するステップ;
(2)培養後の培養液及び/又は菌体より、β-ガラクトシダーゼを回収するステップ。
[15]クリプトコッカス・テレストリスがMM13-F2171株又はその変異株である、[14]に記載の製造法。
[16]以下のステップ(i)及び(ii)を含む、β-ガラクトシダーゼの製造法:
(i)[13]に記載の微生物を、前記遺伝子がコードするタンパク質が産生される条件下で培養するステップ;
(ii)産生された前記タンパク質を回収するステップ。
[17]β-1,3結合、β-1,4結合及びβ-1,6結合の中の少なくとも一つを有する、二糖、オリゴ糖又は多糖に対して、[1]~[9]のいずれか一項に記載のβ-ガラクトシダーゼを作用させるステップを含む、オリゴ糖の製造方法。
[18]ラクトースに対して、[1]~[9]のいずれか一項に記載のβ-ガラクトシダーゼを作用させるステップを含む、オリゴ糖の製造方法。
[19]前記ステップの反応温度が30℃~75℃である、[17]又は[18]に記載の製造方法。
[20][17]~[19]のいずれか一項に記載の製造方法で得られたオリゴ糖。
[21]含有する3糖オリゴ糖の65%以上が直鎖オリゴ糖である、[20]に記載のオリゴ糖。
[22]オリゴ糖の製造のための、[1]~[9]のいずれか一項に記載のβ-ガラクトシダーゼの使用。
本明細書において用語「単離された」は「精製された」と交換可能に使用される。用語「単離された」は、天然の状態、即ち、自然界において存在している状態のものと区別するために使用される。単離するという人為的操作によって、天然の状態とは異なる状態である、「単離された状態」となる。単離されたものは、天然物自体と明確且つ決定的に相違する。
本発明の第1の局面はβ-ガラクトシダーゼ及びその生産菌を提供する。上記の通り、本発明者らは、クリプトコッカス属微生物(野生株)から有用性の高いβ-ガラクトシダーゼ(説明の便宜上、「野生株酵素」と呼ぶ)を取得することに成功するとともにその遺伝子配列を特定した。一方で、変異株が産生する3種類のβ-ガラクトシダーゼ(変異株酵素1、2、3)を同定し、そのアミノ酸配列を特定した。これら3種類のβ-ガラクトシダーゼは、野生株酵素の遺伝子配列から推定した全長アミノ酸配列(配列番号1)の一部であった。具体的には、全長アミノ酸配列(配列番号1)のN末端側130アミノ酸残基が欠損したもの(説明の便宜上、「変異株酵素1」と呼ぶ)、全長アミノ酸配列(配列番号1)のN末端側136アミノ酸残基が欠損したもの(説明の便宜上、「変異株酵素2」と呼ぶ)、全長アミノ酸配列(配列番号1)のN末端側141アミノ酸残基が欠損したもの(説明の便宜上、「変異株酵素3」と呼ぶ)であった。これらの成果及び知見に基づき、本発明のβ-ガラクトシダーゼ(以下、「本酵素」ともいう)は、配列番号1~4のいずれかのアミノ酸配列、又は当該アミノ酸配列と等価なアミノ酸配列を含むという、特徴を備える。配列番号2のアミノ酸配列は変異株酵素1のアミノ酸配列に相当し、配列番号3のアミノ酸配列は変異株酵素2のアミノ酸配列に相当し、配列番号4のアミノ酸配列は変異株酵素3のアミノ酸配列に相当する。
本酵素はラクトース分解活性とガラクトシル転移活性を有し、β-1,6結合、β-1,3結合又はβ-1,2結合への転移活性よりもβ-1,4結合への転移活性が優位である。即ち、本酵素はβ-1,4結合への転移活性に優れる。従って、本酵素によれば、転移した糖がβ-1,4結合で結合した生成物を効率的に得ることができる。例えば、本酵素をラクトース(基質)に作用させると、直鎖オリゴ糖に富む3糖オリゴ糖が得られる。直鎖オリゴ糖は構成単糖がβ-1,4グリコシド結合で連なった構造のオリゴ糖であり、分岐鎖オリゴ糖(β-1,6グリコシド結合やβ-1,2グリコシド結合等を有する)と対照をなす。後述の実施例に示した反応条件(オリゴ糖生成能の検討1の欄)の下、ラクトースを基質として本酵素を作用させた場合に得られる3糖オリゴ糖では、65%以上、好ましくは70%以上、更に好ましくは72%以上、一層好ましくは73%以上、より一層好ましくは75%以上が直鎖オリゴ糖(O-β-D-ガラクトピラノシル-(1→4)-O-β-D-ガラクトピラノシル-(1→4)-D-グルコース)である。尚、本酵素が生成する直鎖オリゴ糖はガラクトオリゴ糖である。一般に、ガラクトオリゴ糖はGal-(Gal)n-Glc(nは0~5程度)で表される(Gal:ガラクトース残基、Glc:グルコース残基)。結合様式にはβ-1,4、β-1,6、β-1,3、β-1,2の他、α-1,3、α-1,6などがある。但し本発明では、ラクトースはガラクトオリゴ糖に該当しないこととする。従って、本明細書において「ガラクトオリゴ糖(GOS)」とは、ラクトースを除いた、重合度が2糖以上のガラクトオリゴ糖のことを意味する。
本酵素の至適温度は70℃である。このように至適温度が高いことは、オリゴ糖の製造用の酵素として有利である。オリゴ糖の製造に本酵素を利用した場合、処理温度(反応温度)を高く設定できる。処理温度を上げることで基質の溶解度が増し、高濃度仕込みが可能となる。その結果、反応液量あたりのガラクトオリゴ糖の生成量(収量)の増加を期待できる。また、濃縮コストの低減も図られる。更には、汚染のリスクの低減も可能となる。尚、至適温度は、酢酸緩衝液(pH6.0)を用い、ラクトースを基質とした測定法によって評価することができる。
本酵素に該当する野生株酵素、変異株酵素1~3はいずれも糖鎖を含み、N型糖鎖とO型糖鎖を除去した後にSDS-PAGEで分子量を測定すると、104 kDa(野生株酵素)、64 kDa(変異株酵素1)、61 kDa(変異株酵素2)、61 kDa(変異株酵素3)であった。この事実に基づき、本酵素の一態様は、糖鎖を含まない場合の分子量(SDS-PAGEによる)が104 kDaである。別の態様では同分子量が64 kDaである。更に別の態様では同分子量が61 kDaである。尚、糖鎖の除去処理をしない場合の分子量(SDS-PAGEによる)は、120 kDa(野生株酵素)、71 kDa(変異株酵素1)、66 kDa変異株酵素2)、66 kDa(変異株酵素3)であった。
(4)至適pH
至適pHは4~5である。至適pHは、例えば、pH2~3のpH域では0.1Mグリシン緩衝液、pH3~6のpH域では0.1Mクエン酸緩衝液、pH5~6のpH域では0.1M酢酸緩衝液、pH7~8のpH域では0.1Mリン酸緩衝、pH9~10のpH域では0.1M炭酸ナトリウム緩衝液中で測定した結果を基に判断される。
一態様の酵素ではpH2~8のpH域、別の態様の酵素ではpH2~9のpH域で安定した活性を示す。即ち、処理に供する酵素溶液のpHがこの範囲内にあれば、40℃、30分の処理後、最大活性の80%以上の活性を示す。pH安定性は、例えば、pH2~3のpH域では0.1Mグリシン緩衝液、pH3~6のpH域では0.1Mクエン酸緩衝液、pH5~6のpH域では0.1M酢酸緩衝液、pH7~8のpH域では0.1Mリン酸緩衝、pH9~10のpH域では0.1M炭酸ナトリウム緩衝液中で測定した結果を基に判断される。
一態様の酵素は酢酸緩衝液(pH6.0)中、30℃~60℃の条件で30分間処理しても80%以上の活性を維持する。別の態様の酵素は酢酸緩衝液(pH6.0)中、30℃~65℃の条件で30分間処理しても80%以上の活性を維持する。
<クリプトコッカス・テレストリスMM13-F2171株>
寄託機関:独立行政法人製品評価技術基盤機構 特許微生物寄託センター(〒292-0818 日本国千葉県木更津市かずさ鎌足2-5-8 122号室)
識別の表示:Cryptococcus terrestris MM13-F2171
寄託日:2015年12月10日
受託番号:NITE BP-02177
寄託機関:独立行政法人製品評価技術基盤機構 特許微生物寄託センター(〒292-0818 日本国千葉県木更津市かずさ鎌足2-5-8 122号室)
識別の表示:Cryptococcus terrestris APC-6431
寄託日:2015年12月10日
受託番号:NITE BP-02178
本発明の第2の局面は本酵素をコードする遺伝子に関する。一態様において本発明の遺伝子は、配列番号1~4のいずれかのアミノ酸配列をコードするDNAを含む。当該態様の具体例は、配列番号5の塩基配列からなるcDNA(配列番号1のアミノ酸配列をコードする)、配列番号6の塩基配列からなるcDNA(配列番号2のアミノ酸配列をコードする)、配列番号7の塩基配列からなるcDNA(配列番号3のアミノ酸配列をコードする)、及び配列番号8の塩基配列からなるcDNA(配列番号4のアミノ酸配列をコードする)である。更なる具体例は、配列番号16の塩基配列からなるゲノムDNAである。当該ゲノムDNAは配列番号5のcDNAに対応する。
本発明の第2の局面はβ-ガラクトシダーゼの製造方法を提供する。本発明の製造方法の一態様では、クリプトコッカス・テレストリスを培養するステップ(ステップ(1))と培養後の培養液及び/又は菌体よりβ-ガラクトシダーゼを回収するステップ(ステップ(2))を行う。好ましくは、クリプトコッカス・テレストリスとして、MM13-F2171株又はその変異株(例えば、クリプトコッカス・テレストリスAPC-6431(M2株)や当該株の更なる変異株)を用いる。培養条件や培養法は、本酵素が生産されるものである限り特に限定されない。即ち、本酵素が生産されることを条件として、使用する微生物の培養に適合した方法や培養条件を適宜設定できる。培養法としては液体培養、固体培養のいずれでも良いが、好ましくは液体培養が利用される。液体培養を例にとり、その培養条件を説明する。
本酵素は例えば酵素剤の形態で提供される。本酵素剤は、有効成分(即ち、本酵素)の他、賦形剤、緩衝剤、懸濁剤、安定剤、保存剤、防腐剤、生理食塩水などを含有していてもよい。有効成分である本酵素の精製度は特に問わない。即ち、粗酵素であっても精製酵素であってもよい。賦形剤としては乳糖、ソルビトール、D-マンニトール、マルトデキストリン、白糖、食塩等を用いることができる。緩衝剤としてはリン酸塩、クエン酸塩、酢酸塩等を用いることができる。安定剤としてはプロピレングリコール、アスコルビン酸等を用いることができる。保存剤としてはフェノール、塩化ベンザルコニウム、ベンジルアルコール、クロロブタノール、メチルパラベン等を用いることができる。防腐剤としては塩化ベンザルコニウム、パラオキシ安息香酸、クロロブタノール等と用いることができる。
本発明の更なる局面は本酵素又は本酵素剤の用途を提供する。用途の例は、ガラクトオリゴ糖の製造、低乳糖牛乳の製造、或いは乳糖不耐症患者のための医薬やサプリメントの製造である。ガラクトオリゴ糖は、例えば腸内ビフィズス菌増殖因子として利用される。本酵素又は本酵素剤はガラクトオリゴ糖の製造において特に有用である。本酵素又は本酵素剤によれば、ラクトースを原料として、直鎖オリゴ糖に富む(即ち、分岐鎖オリゴ糖に比較して直鎖オリゴ糖の割合が多い)ガラクトオリゴ糖を製造することができる。ガラクトオリゴ糖を製造する場合には、例えば、予め加熱溶解させた30%~65%ラクトース液(pH 5.0)1 Lに75 U~5000 Uの本酵素を加え、30℃~75℃、15時間~50時間、反応させ、ガラクトオリゴ糖を生成させる。本酵素は至適温度が高いことから、処理温度(反応温度)を高く(例えば40℃~75℃、好ましくは50℃~75℃、更に好ましくは60℃~75℃、一層好ましくは65℃~75℃)設定できる。処理温度を上げることで基質の溶解度が増し、高濃度仕込みが可能となる。本酵素又は本酵素剤を用いてオリゴ糖を製造する際の原料(基質)はラクトースが好ましいが、これに限定されるものではない。β-1,3結合、β-1,4結合及びβ-1,6結合の中の少なくとも一つを有する、二糖、オリゴ糖又は多糖を原料として採用することが可能である。
ガラクトオリゴ糖の製造に適したβ-ガラクトシダーゼの取得を目指し、広範な種類の微生物を対象にスクリーニングした。その結果、独立行政法人製品評価技術基盤機構による「アジア地域における生物遺伝資源の保全と持続可能な利用に関する共同事業」にて2013年10月にミャンマーのHeho空港近くで採取した土壌試料に含まれていたクリプトコッカス・テレストリスが有望な産生菌であることが判明した。そこで、当該菌株(クリプトコッカス・テレストリスMM13-F2171株)からβ-ガラクトシダーゼの精製を試みた。尚、クリプトコッカス・テレストリスMM13-F2171株はCryptococcus terrestris MM13-F2171の名称で2015年12月10日に独立行政法人製品評価技術基盤機構 特許微生物寄託センターに寄託され、受託番号NITE BP-02177が付与された。
12% ラクトースを含む0.1 M酢酸緩衝液(pH 6.0) 5.0 mLを量り、40℃で10分間予温する。サンプル1 mLを添加し、40℃で10分間放置した後、1.5 M水酸化ナトリウム1.0 mLを加え、さらに、40℃で5分間放置し反応を停止する。この溶液を氷水槽中で冷やした後、1.5 M塩酸1.0 mLを添加し中和させた。この反応液100μlについてグルコスタット法(和光純薬工業 グルコースキット グルコースCII-テストワコー)を用いて反応液中のグルコース量を測定した。1分間当たり、1μmolに相当するグルコースを生成する酵素量を1Uとした。
液体培地(2.0% ラクトース、2.0% Yeast Extract、0.1% KH2PO4、0.05% MgSO4・7H2O、pH 5.0)でクリプトコッカス・テレストリスMM13-F2171株を30℃、4日間振とう培養(200 回転/分)した。培養後、遠心分離により上清を約3L回収し、限外ろ過膜(AIP-1013D 膜内径0.8mm(旭化成ケミカルズ株式会社))を用いて濃縮・脱塩処理を行った。脱塩処理の際には、20mM酢酸緩衝液pH6.0を用いた。
精製酵素のアミノ酸配列を解析した結果、以下の配列が含まれていることが判明した。
GVQYVDYNSPT(配列番号9)
FLFGWATAAQQ(配列番号10)
QAYQIGIFAEPIYNT(配列番号11)
PSIWDWAS(配列番号12)
EEPPFAYVPE(配列番号13)
クリプトコッカス・テレストリスMM13-F2171株が産生するβ-ガラクトシダーゼをコードする遺伝子配列の同定を試みた。液体培地(2.0% ラクトース、2.0% Yeast Extract、0.1% KH2PO4、0.05% MgSO4・7H2O、pH 5.0)でクリプトコッカス・テレストリスMM13-F2171株を30℃、24時間振とう培養(200 回転/分)した。培養後、集菌した。RNeasy Mini Kit (QIAGEN) の酵母からのRNA抽出(機械による菌体破砕)のプロトコールに従って全RNAを調製した。得られた全RNAから、SMARTer RACE 5'/ 3' kit (TaKaRa)を用いてcDNAを合成し、5'及び3'RACE PCRを実施した。5'RACE用GSPプライマーにはGATTACGCCAAGCTTgcaaagatcccgatctggtacgcctg(配列番号14)、3'RACE用GSPプライマーにはGATTACGCCAAGCTTttcctgtttggctgggcgaccgcc(配列番号15)を用いた。得られたRACE PCR産物の塩基配列を解析し、全長cDNA配列(配列番号5)を決定した。なお、全長cDNA配列によってコードされる推定アミノ酸配列を配列番号1に示す。
(1)至適pHとpH安定性
ラクトース分解活性を指標として、精製酵素の至適pHとpH安定性を検討した。至適pH検討には、pH2~3のpH域では0.1Mグリシン緩衝液、pH3~6のpH域では0.1Mクエン酸緩衝液、pH5~6のpH域では0.1M酢酸緩衝液、pH7~8のpH域では0.1Mリン酸緩衝、pH9~10のpH域では0.1M炭酸ナトリウム緩衝液を使用した。測定結果を図2に示す。精製酵素の至適pHは4~5であった。
至適温度を検討するため、酢酸緩衝液(pH6.0)を用い、各温度でのラクトース分解活性を測定した。結果を図4に示す。至適温度は70℃であった。温度安定性を検討するため、酢酸緩衝液(pH6.0)中、各温度で30分間加熱後、ラクトース分解活性を測定した。結果を図5に示す。30℃~60℃で安定であり、活性は80%以上保持されていた。
(1)方法
精製酵素のオリゴ糖生成能を検討した。反応温度に予温した53%ラクトース溶液に野生株酵素をラクトース1gあたり1U添加し、各温度で24時間反応させた。HPLCで分析し(以下の条件)、反応後の溶液に含まれる糖の組成を調べた。尚、糖組成の測定結果から、転移活性を評価することができる。
使用カラム:MCITMGEL CK04S(三菱化学)
溶出液:H2O
流速:0.4 ml/分
検出器:RI
カラム温度:80℃
使用カラム:Shodex(登録商標) Asahipak NH2P-40 3E(昭和電工株式会社)
溶出液:MeCN:H2O=75:25 (vol:vol)
流速:0.35 ml/分
検出器:RI
カラム温度:25℃
測定結果から、反応温度毎、反応液に含まれる糖(全糖)に占めるガラクトオリゴ糖(GOS)の割合(%)とGOS中の重合度の比率(%)を算出した(図6)。精製酵素(野生株酵素)はGOS生成能に優れることがわかる。また、高温条件下で高い転移活性を示し、オリゴ糖の製造に有用といえる。
クリプトコッカス・テレストリスMM13-F2171株から、UV処理による変異によって2種類の変異株(M2株とM6株)を得た。これら変異株の産生するβ-ガラクトシダーゼを上記1.(2)と同様の手順で精製した。M2株とM6株はいずれも変異株酵素1~3の産生能を有するが、M2株は変異株酵素1の産生能が特に高く、M6株は変異株酵素2及び変異株酵素3の産生能が特に高い。尚、クリプトコッカス・テレストリスM2株は、Cryptococcus terrestris APC-6431の名称で2015年12月10日に独立行政法人製品評価技術基盤機構 特許微生物寄託センターに寄託され、受託番号NITE BP-02178が付与された。
<無処理の場合>
変異株酵素1(レーン1、5):71 kDa
変異株酵素2(レーン1、5):66 kDa
変異株酵素3(レーン1、5):66 kDa
<O型糖鎖を除去した場合>
変異株酵素1(レーン2、6):65 kDa
変異株酵素2(レーン2、6):63 kDa
変異株酵素3(レーン2、6):62 kDa
<N型糖鎖を除去した場合>
変異株酵素1(レーン3、7):64 kDa
変異株酵素2(レーン3、7):61 kDa
変異株酵素3(レーン3、7):61 kDa
<O型糖鎖とN型糖鎖を除去した場合>
変異株酵素1(レーン4、8):64 kDa
変異株酵素2(レーン4、8):61 kDa
変異株酵素3(レーン4、8):61 kDa
(1)方法
ラクトース溶液にM2株由来の精製酵素(変異株酵素1)又はM6株由来の精製酵素(変異株酵素3)を添加して反応させ、反応後の溶液に含まれる糖の重合度及び分岐度を調べた。反応条件、重合度及び分岐度の測定は上記5.に準じた。
測定結果から、反応温度毎、反応液に含まれる糖(全糖)に占めるGOSの割合(%)とGOS中の重合度の比率(%)を算出した(図9)。精製酵素(変異株酵素)はGOS生成能に優れることがわかる。また、高温条件下で高い転移活性を示し、オリゴ糖の製造に有用といえる。また、野生株酵素と変異株酵素のGOS生成能に差がないことがわかる。
精製酵素(上記6.を参照)を用い、変異株酵素1及び変異株酵素3の性質を確認した。実験方法は野生株酵素の場合(上記4.を参照)と同様とした。
(1)至適pHとpH安定性
至適pHに関する測定結果を図11(変異株酵素1)と図12(変異株酵素3)に示す。変異株酵素1及び変異株酵素3の至適pHはいずれも4~5であった。一方、pH安定性に関する測定結果を図13(変異株酵素1)と図14(変異株酵素3)に示す。変異株酵素1及び変異株酵素3はいずれもpH2~9のpH域で安定した活性を示した。
至適温度に関する測定結果を図15(変異株酵素1)と図16(変異株酵素3)に示す。変異株酵素1及び変異株酵素3の至適温度はいずれも70℃であった。一方、温度安定性に関する測定結果を図17(変異株酵素1)と図18(変異株酵素3)に示す。変異株酵素1及び変異株酵素3はいずれも30℃~65℃で安定であり、活性は80%以上保持されていた。
Claims (22)
- 配列番号1~4のいずれかのアミノ酸配列、又は該アミノ酸配列と80%以上同一のアミノ酸配列を含む、β-ガラクトシダーゼ。
- アミノ酸配列が、配列番号1~4のいずれかのアミノ酸配列と85%以上同一のアミノ酸配列である、請求項1に記載のβ-ガラクトシダーゼ。
- アミノ酸配列が、配列番号1~4のいずれかのアミノ酸配列と90%以上同一のアミノ酸配列である、請求項1に記載のβ-ガラクトシダーゼ。
- 配列番号1の配列の長さを超えない長さのアミノ酸配列からなる、請求項1~3のいずれか一項に記載のβ-ガラクトシダーゼ。
- 下記の酵素化学的性質を有するβ-ガラクトシダーゼ、
(1)作用:ラクトース分解活性とガラクトシル転移活性を有し、β-1,6結合、β-1,3結合又はβ-1,2結合への転移活性よりもβ-1,4結合への転移活性が優位である、
(2)至適温度:70℃、
(3)糖鎖を含まない場合の分子量:約104 kDa、約64 kDa、又は約61 kDa(SDS-PAGEによる)。 - 下記の酵素化学的性質を更に有する、請求項5に記載のβ-ガラクトシダーゼ、
(4)至適pH:4~5、
(5)pH安定性:pH2~8の範囲で安定(40℃、30分間)、
(6)温度安定性:30℃~60℃の範囲で安定(pH6.0、30分間)。 - 下記の酵素化学的性質を更に有する、請求項5に記載のβ-ガラクトシダーゼ、
(4)至適pH:4~5、
(5)pH安定性:pH2~9の範囲で安定(40℃、30分間)、
(6)温度安定性:30℃~65℃の範囲で安定(pH6.0、30分間)。 - クリプトコッカス・テレストリス由来である、請求項1~7のいずれか一項に記載のβ-ガラクトシダーゼ。
- クリプトコッカス・テレストリスがMM13-F2171株(受託番号:NITE BP-02177)又はAPC-6431株(受託番号:NITE BP-02178)である、請求項8に記載のβ-ガラクトシダーゼ。
- 請求項1~9のいずれか一項に記載のβ-ガラクトシダーゼを有効成分とする酵素剤。
- 以下の(a)~(c)からなる群より選択されるいずれかのDNAからなるβ-ガラクトシダーゼ遺伝子:
(a)配列番号1~4のいずれかのアミノ酸配列をコードするDNA;
(b)配列番号5~8、16いずれかの塩基配列からなるDNA;
(c)配列番号5~8、16のいずれかの塩基配列と等価な塩基配列を有し、且つβ-ガラクトシダーゼ活性を有するタンパク質をコードするDNA。 - 請求項11に記載のβ-ガラクトシダーゼ遺伝子を含む組換えDNA。
- 請求項12に記載の組換えDNAを保有する微生物。
- 以下のステップ(1)及び(2)を含む、β-ガラクトシダーゼの製造法:
(1)クリプトコッカス・テレストリスを培養するステップ;
(2)培養後の培養液及び/又は菌体より、β-ガラクトシダーゼを回収するステップ。 - クリプトコッカス・テレストリスがMM13-F2171株又はその変異株である、請求項14に記載の製造法。
- 以下のステップ(i)及び(ii)を含む、β-ガラクトシダーゼの製造法:
(i)請求項13に記載の微生物を、前記遺伝子がコードするタンパク質が産生される条件下で培養するステップ;
(ii)産生された前記タンパク質を回収するステップ。 - β-1,3結合、β-1,4結合及びβ-1,6結合の中の少なくとも一つを有する、二糖、オリゴ糖又は多糖に対して、請求項1~9のいずれか一項に記載のβ-ガラクトシダーゼを作用させるステップを含む、オリゴ糖の製造方法。
- ラクトースに対して、請求項1~9のいずれか一項に記載のβ-ガラクトシダーゼを作用させるステップを含む、オリゴ糖の製造方法。
- 前記ステップの反応温度が30℃~75℃である、請求項17又は18に記載の製造方法。
- 請求項17~19のいずれか一項に記載の製造方法で得られたオリゴ糖。
- 含有する3糖オリゴ糖の65%以上が直鎖オリゴ糖である、請求項20に記載のオリゴ糖。
- オリゴ糖の製造のための、請求項1~9のいずれか一項に記載のβ-ガラクトシダーゼの使用。
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AU2016382107A AU2016382107B2 (en) | 2015-12-29 | 2016-12-27 | Novel beta-galactosidase |
US16/065,400 US11512299B2 (en) | 2015-12-29 | 2016-12-27 | Beta-galactosidase enzymes |
JP2017559227A JP7122114B2 (ja) | 2015-12-29 | 2016-12-27 | 新規β-ガラクトシダーゼ |
EP16881800.3A EP3399032A4 (en) | 2015-12-29 | 2016-12-27 | NOVEL BETA GALACTOSIDASE |
CA3009043A CA3009043A1 (en) | 2015-12-29 | 2016-12-27 | Novel .beta.-galactosidase |
CN201680076645.0A CN108699549B (zh) | 2015-12-29 | 2016-12-27 | β-半乳糖苷酶 |
US17/961,625 US11859222B2 (en) | 2015-12-29 | 2022-10-07 | Beta-galactosidase enzymes |
US18/503,526 US20240084278A1 (en) | 2015-12-29 | 2023-11-07 | Beta-galactosidase enzymes |
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WO2020100706A1 (ja) * | 2018-11-13 | 2020-05-22 | 株式会社ヤクルト本社 | 分泌型のβ-ガラクトシダーゼの製造方法 |
WO2020141032A1 (en) | 2019-01-02 | 2020-07-09 | Frieslandcampina Nederland B.V. | Method for preparing gos-preparation with beta-galactosidase from cryptococcus terrestris, gos preparations obtainable thereby and uses thereof |
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