JP2759716B2 - Method for controlling molecular weight of poly-γ-glutamic acid - Google Patents
Method for controlling molecular weight of poly-γ-glutamic acidInfo
- Publication number
- JP2759716B2 JP2759716B2 JP8721591A JP8721591A JP2759716B2 JP 2759716 B2 JP2759716 B2 JP 2759716B2 JP 8721591 A JP8721591 A JP 8721591A JP 8721591 A JP8721591 A JP 8721591A JP 2759716 B2 JP2759716 B2 JP 2759716B2
- Authority
- JP
- Japan
- Prior art keywords
- molecular weight
- pga
- glutamic acid
- poly
- reaction
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Polyamides (AREA)
Description
【0001】[0001]
【産業上の利用分野】本発明は、ポリ−γ−グルタミン
酸の分子量制御法に関し、詳しくは微生物を用いて容易
に製造されるポリ−γ−グルタミン酸(以下、PGAと
略記することがある。)を原料とし、これを溶液中で求
核試剤と反応させて低分子量化することよりなるPGA
の分子量制御法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the molecular weight of poly-.gamma.-glutamic acid, and more particularly to poly-.gamma.-glutamic acid (hereinafter abbreviated as PGA) which is easily produced by using a microorganism. , Which is reacted with a nucleophilic reagent in a solution to reduce the molecular weight of PGA
And a molecular weight control method.
【0002】[0002]
【従来の技術及び発明が解決しようとする課題】本発明
者らは既にグルタミン酸のγ−カルボキシル基とα−ア
ミノ基がアミド結合により結合している化合物であるP
GAの高度重合体を微生物を用いて有利に製造する方法
を確立した(特開平1−174397)。また、PGA
の有するα−カルボキシル基を経済的にアルキル基また
はベンジル基によりエステル化することにより産業上有
用なポリ−γ−グルタミン酸 α−置換 エステル(以
下、PGAエステル化物と略記することがある。)を得
ることに成功している(特願平2−28754)。BACKGROUND OF THE INVENTION The inventors of the present invention have already proposed a compound, a compound in which the γ-carboxyl group and the α-amino group of glutamic acid are linked by an amide bond.
A method for advantageously producing a high polymer of GA using a microorganism has been established (JP-A-1-17497). Also, PGA
The α-carboxyl group of the above is economically esterified with an alkyl group or a benzyl group to obtain an industrially useful poly-γ-glutamic acid α-substituted ester (hereinafter sometimes abbreviated as a PGA esterified product). This has been successful (Japanese Patent Application No. 2-28754).
【0003】しかし、上記PGAは高極性溶媒にのみ可
溶であるという性質のため、広範な用途開発の障害とな
っていた。PGAが溶媒可溶性に劣る原因として、PG
Aの分子量の大きさ,構成アミノ酸の光学異性,アミド
結合のもつ固有の性質などが考えられる。[0003] However, the above-mentioned properties of PGA that are soluble only in highly polar solvents have hindered the development of a wide range of applications. PGA is inferior in solvent solubility due to PG
The molecular weight of A, the optical isomerism of the constituent amino acids, the inherent properties of the amide bond, and the like are considered.
【0004】[0004]
【課題を解決するための手段】そこで、本発明者らはP
GAを種々の溶媒に可溶性とすべく、PGAの金属塩等
を求核試剤と反応させてPGAの分子量を低下させる方
法について検討を重ねた。その結果、微生物の生産する
PGAの金属塩またはアンモニウム塩を水に溶かした
後、求核試剤を添加して加温すると、γ−アミド結合が
分解され、低分子量化することを見出し、本発明を完成
したのである。Means for Solving the Problems Accordingly, the present inventors have proposed P
In order to make GA soluble in various solvents, a method of reducing the molecular weight of PGA by reacting a metal salt of PGA with a nucleophilic reagent was repeated. As a result, it has been found that when a metal salt or ammonium salt of PGA produced by a microorganism is dissolved in water, and a nucleophilic reagent is added thereto and heated, the γ-amide bond is decomposed and the molecular weight is reduced. Was completed.
【0005】すなわち、本発明は下記の繰り返し単位を
有するポリ−γ−グルタミン酸を溶液中で、前記ポリ−
γ−グルタミン酸のもつアミド結合の1.0〜10.0
当量の割合の求核試剤と反応させ、固有粘度0.3〜
0.4dl/gのポリ−γ−グルタミン酸を得ることを
特徴とするポリ−γ−グルタミン酸の分子量制御法を提
供するものである。Namely, the present invention in solution of poly -γ- glutamic acid having a repeating unit of the following, the poly -
1.0 to 10.0 of the amide bond of γ-glutamic acid
React with an equivalent ratio of nucleophilic reagent, intrinsic viscosity 0.3-
An object of the present invention is to provide a method for controlling the molecular weight of poly-γ-glutamic acid, which comprises obtaining 0.4 dl / g of poly-γ-glutamic acid .
【化2】 Embedded image
【0006】本発明の原料であるPGAは、例えば特開
平1−174397号公報に記載の方法により製造され
たものを使用することができる。PGAの分子量は、ゲ
ル濾過−光散乱法により測定したときの数平均分子量が
概ね1.0×106以上を示し、本分析値より算出した
重合度は1.0×104程度またはそれ以上を示す。ま
た、高分子物質の分子量として慣用される固有粘度をP
GA可溶溶媒であるジメチルスルホキシド(以下、DM
SOと略記することがある。)にPGAを1重量%溶解
し、30℃の恒温槽中にて測定すると、1.0dl/g
以上の値を示す。本発明により低分子量化されたPGA
とは、固有粘度が0.3〜0.4dl/gのものを意味
する。 As the raw material of the present invention, for example, PGA produced by the method described in JP-A-1-17497 can be used. Regarding the molecular weight of PGA, the number average molecular weight as measured by gel filtration-light scattering method generally indicates 1.0 × 10 6 or more, and the degree of polymerization calculated from this analysis value is about 1.0 × 10 4 or more. Is shown. In addition, the intrinsic viscosity commonly used as the molecular weight of a polymer substance is represented by P
Dimethyl sulfoxide (hereinafter referred to as DM
It may be abbreviated as SO. ) Was dissolved at 1% by weight and measured in a thermostat at 30 ° C., and found to be 1.0 dl / g.
The above values are shown. PGA reduced in molecular weight by the present invention
Means those having an intrinsic viscosity of 0.3 to 0.4 dl / g
I do.
【0007】本発明によるPGAの分子量制御反応に
は、PGA(遊離酸型)可溶溶媒であるDMSO,ジメ
チルホルムアミド(以下、DMFと略記することがあ
る。),N−メチルピロリドン,ジメチルイミダゾリジ
ノンなどの非プロトン性高極性溶媒や、PGA(塩型)
可溶溶媒である水等が使用でき、特に水を用いることが
好ましい。なお、PGA溶液の濃度は0.02〜20重
量%の範囲とすべきであり、反応後の回収率の高さを考
慮すると、1.0重量%以上の濃度で用いることが望ま
しい。In the molecular weight control reaction of PGA according to the present invention, DMSO, dimethylformamide (hereinafter sometimes abbreviated as DMF) which is a PGA (free acid type) soluble solvent, N-methylpyrrolidone, dimethylimidazolidy. Non-protonic highly polar solvents such as non-, PGA (salt type)
Water or the like, which is a soluble solvent, can be used, and it is particularly preferable to use water. The concentration of the PGA solution should be in the range of 0.02 to 20% by weight, and considering the high recovery after the reaction, it is preferable to use the PGA solution at a concentration of 1.0% by weight or more.
【0008】次に、本発明に使用する求核試剤としては
アルカリ金属水酸化物またはヒドラジンを挙げることが
でき、具体的には水酸化ナトリウム,水酸化カリウム,
無水ヒドラジン,1,1−ジメチルヒドラジン等があ
る。求核試剤の添加量は、PGAのもつアミド結合の
1.0〜10.0当量、好ましくは1.1〜2.0当量
が適当である。Next, examples of the nucleophilic reagent used in the present invention include alkali metal hydroxides and hydrazines. Specifically, sodium hydroxide, potassium hydroxide,
Examples include anhydrous hydrazine and 1,1-dimethylhydrazine. The amount of the nucleophilic reagent to be added is 1.0 to 10.0 equivalents of the amide bond of PGA, preferably 1.1 to 2.0 equivalents.
【0009】反応温度は、溶媒として水を使用した場
合、水の氷結温度から沸騰温度までを採用できるが、6
0℃以上が好ましい。また、反応時間は、反応温度や要
求されるPGAの分子量などにより異なるが、例えば8
0℃のとき24時間程度でPGAが完全に分解されるこ
とを目安として、または反応液の粘度を測定することに
より適宜決定すればよい。When water is used as the solvent, the reaction temperature can be from the freezing temperature to the boiling temperature of water.
0 ° C. or higher is preferred. The reaction time varies depending on the reaction temperature and the required molecular weight of PGA.
It may be determined appropriately based on the assumption that PGA is completely decomposed in about 24 hours at 0 ° C. or by measuring the viscosity of the reaction solution.
【0010】反応終了後、分子量制御されたPGAは、
溶媒として水を使用した場合、反応液を塩酸,硫酸など
の無機酸によりpHを1.0〜1.5に調整した後、4
℃で2〜3日放置することによって析出させることがで
きる。また、有機溶媒を使用した場合、反応液の1〜6
倍量のジエチルエーテルに反応液を投入することによっ
て低分子量のPGAを高収率で回収することができる。After completion of the reaction, the molecular weight-controlled PGA is
When water is used as the solvent, the pH of the reaction solution is adjusted to 1.0 to 1.5 with an inorganic acid such as hydrochloric acid, sulfuric acid, and the like.
It can be precipitated by leaving it at a temperature of 2 to 3 days. When an organic solvent is used, 1 to 6 of the reaction solution is used.
By pouring the reaction solution into twice as much diethyl ether, low molecular weight PGA can be recovered in high yield.
【0011】[0011]
【実施例】次に、本発明を実施例により具体的に説明す
る。 実施例1 PGA8.0gを190mlの脱イオン水に懸濁した
後、2.06gの水酸化ナトリウムを添加して室温で1
7時間撹拌し、完全に溶解させた。溶液温度を60℃に
上昇させ、60℃となった後、3.72gの水酸化ナト
リウムを含む10mlの溶液を反応液に添加し、反応を
開始した。低分子量化された精製PGAの分子量の指標
としてDMSOの1.0重量%溶液として固有粘度を測
定し、反応時間との関係を調べた。結果を図1に示す。
なお、対照として反応を25℃で行ったこと以外は同様
にした場合の結果も図1に示した。Next, the present invention will be described in detail with reference to examples. Example 1 After 8.0 g of PGA was suspended in 190 ml of deionized water, 2.06 g of sodium hydroxide was added thereto, and the suspension was added at room temperature.
Stir for 7 hours to completely dissolve. The solution temperature was raised to 60 ° C., and after the temperature reached 60 ° C., 10 ml of a solution containing 3.72 g of sodium hydroxide was added to the reaction solution to start the reaction. The intrinsic viscosity was measured as a 1.0% by weight solution of DMSO as an index of the molecular weight of the purified PGA having a reduced molecular weight, and the relationship with the reaction time was examined. The results are shown in FIG.
FIG. 1 also shows the results when the reaction was carried out in the same manner except that the reaction was carried out at 25 ° C. as a control.
【0012】図から明らかなように、対照の場合は反応
時間に関係なくPGAの低分子化が殆ど認められない
が、本発明の場合は反応時間の経過と共にPGAが低分
子化する。58時間反応後、反応液のpHを2規定塩酸
を用いて1.0〜2.0の範囲に調整したのち4℃で4
8時間放置してPGAを析出させた。析出したPGAを
濾別し、少量のメタノールで洗浄したのち40℃で4時
間減圧乾燥して粉末5.6g(収率70%)を得た。こ
の粉末の元素分析値を以下に示す。炭素 45.52
%;水素 5.57%;窒素 10.42%;無機物
0%As is apparent from the figure, in the case of the control, the molecular weight of PGA is hardly reduced irrespective of the reaction time, but in the case of the present invention, the molecular weight of PGA is reduced with the lapse of the reaction time. After the reaction for 58 hours, the pH of the reaction solution was adjusted to a range of 1.0 to 2.0 using 2N hydrochloric acid, and then adjusted to 4 ° C at 4 ° C.
PGA was precipitated by standing for 8 hours. The precipitated PGA was separated by filtration, washed with a small amount of methanol, and dried under reduced pressure at 40 ° C. for 4 hours to obtain 5.6 g of powder (yield: 70%). The elemental analysis values of this powder are shown below. 45.52 carbon
%; Hydrogen 5.57%; nitrogen 10.42%; inorganics
0%
【0013】実施例2 PGA8.0gを190mlの脱イオン水に懸濁した
後、無水ヒドラジン7.81gを添加して室温で2時間
撹拌し、完全に溶解させた。溶液温度を60℃に上昇さ
せて反応を開始した。低分子量化された精製PGAの分
子量の指標としてDMSOの1.0重量%溶液として固
有粘度を測定し、反応時間との関係を調べた。結果を図
2に示す。なお、対照として反応を25℃で行ったこと
以外は同様にした場合の結果も図2に示した。Example 2 After 8.0 g of PGA was suspended in 190 ml of deionized water, 7.81 g of anhydrous hydrazine was added and stirred at room temperature for 2 hours to completely dissolve. The reaction was started by raising the solution temperature to 60 ° C. The intrinsic viscosity was measured as a 1.0% by weight solution of DMSO as an index of the molecular weight of the purified PGA having a reduced molecular weight, and the relationship with the reaction time was examined. The results are shown in FIG. FIG. 2 also shows the results when the reaction was carried out at 25 ° C. as a control.
【0014】図から明らかなように、対照の場合は反応
時間に関係なくPGAの低分子化が殆ど認められない
が、本発明の場合は反応時間の経過と共にPGAが低分
子化する。反応終了後、反応液のpHを2規定塩酸を用
いて1.5に調整したのち4℃で48時間放置してPG
Aを析出させた。析出したPGAを濾別して粉末6.8
g(収率85%)を得た。As is apparent from the figure, in the case of the control, the reduction of the molecular weight of PGA is hardly recognized irrespective of the reaction time, but in the case of the present invention, the molecular weight of PGA is reduced with the lapse of the reaction time. After completion of the reaction, the pH of the reaction solution was adjusted to 1.5 using 2N hydrochloric acid, and then left at 4 ° C. for 48 hours to obtain PG.
A was precipitated. The precipitated PGA was filtered off to give powder 6.8.
g (85% yield).
【0015】[0015]
【発明の効果】本発明によれば、商業的に安定的かつ安
価に入手可能なPGAを原料として低分子化されたPG
Aを効率よく製造することができる。According to the present invention, a low molecular weight PG is obtained from PGA which is commercially stable and can be obtained at low cost.
A can be manufactured efficiently.
【0016】[0016]
【図1】 実施例1における反応時間とPGAの分子量
の関係を示すグラフである。FIG. 1 is a graph showing the relationship between the reaction time and the molecular weight of PGA in Example 1.
【図2】 実施例2における反応時間とPGAの分子量
の関係を示すグラフである。FIG. 2 is a graph showing the relationship between the reaction time and the molecular weight of PGA in Example 2.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 土肥義治編 「生分解性高分子材料」 (1990−11−9) 株式会社工業調査 会 P.124−126 (58)調査した分野(Int.Cl.6,DB名) C08G 69/46 C07C 231/08 C07C 237/22──────────────────────────────────────────────────続 き Continued on the front page (56) Reference “Yoshiharu Toi” edited by “Biodegradable Polymer Materials” (1990-11-9) 124-126 (58) Field surveyed (Int. Cl. 6 , DB name) C08G 69/46 C07C 231/08 C07C 237/22
Claims (2)
グルタミン酸を溶液中で、前記ポリ−γ−グルタミン酸
のもつアミド結合の1.0〜10.0当量の割合の求核
試剤と反応させ、固有粘度0.3〜0.4dl/gのポ
リ−γ−グルタミン酸を得ることを特徴とするポリ−γ
−グルタミン酸の分子量制御法。 【化1】 1. Poly-γ- having the following repeating unit:
Glutamic acid in solution, the poly-γ-glutamic acid
Of amide bond having a ratio of 1.0 to 10.0 equivalents
React with the reagent to obtain a powder with an intrinsic viscosity of 0.3 to 0.4 dl / g.
Poly-γ characterized by obtaining ly-γ-glutamic acid
-A method for controlling the molecular weight of glutamic acid. Embedded image
ヒドラジンである請求項1記載の方法。2. The method according to claim 1, wherein the nucleophile is an alkali metal hydroxide or hydrazine.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP8721591A JP2759716B2 (en) | 1991-03-28 | 1991-03-28 | Method for controlling molecular weight of poly-γ-glutamic acid |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP8721591A JP2759716B2 (en) | 1991-03-28 | 1991-03-28 | Method for controlling molecular weight of poly-γ-glutamic acid |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH04300860A JPH04300860A (en) | 1992-10-23 |
JP2759716B2 true JP2759716B2 (en) | 1998-05-28 |
Family
ID=13908702
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP8721591A Expired - Lifetime JP2759716B2 (en) | 1991-03-28 | 1991-03-28 | Method for controlling molecular weight of poly-γ-glutamic acid |
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Country | Link |
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JP (1) | JP2759716B2 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102666566A (en) * | 2009-12-16 | 2012-09-12 | 日东电工株式会社 | Controlled synthesis of polyglutamic acid |
-
1991
- 1991-03-28 JP JP8721591A patent/JP2759716B2/en not_active Expired - Lifetime
Non-Patent Citations (1)
Title |
---|
土肥義治編 「生分解性高分子材料」 (1990−11−9) 株式会社工業調査会 P.124−126 |
Also Published As
Publication number | Publication date |
---|---|
JPH04300860A (en) | 1992-10-23 |
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