• Title/Summary/Keyword: 선택적 가수분해

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Enantioselective Hydrolysis for Preparing (S)-Styrene Oxide in Organic Solvents Using Recombinant Escherichia coli Expressing Protein-engineered Epoxide Hydrolase of Mugil cephalus (Mugil cephalus 유래 에폭사이드 가수분해효소를 발현하는 재조합 대장균을 이용한 유기용매에서의 (S)-Styrene Oxide 제조를 위한 입체선택적 가수분해 반응)

  • Lee, Ok Kyung;Lee, Eun Yeol
    • Applied Chemistry for Engineering
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    • v.23 no.6
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    • pp.599-603
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    • 2012
  • The enantioselective hydrolysis of racemic styrene oxide in organic solvents was conducted using a recombinant E. coli expressing protein-engineered Mugil cephalus epoxide hydrolase (McEH). The volumetric total activity of the recombinant E. coli was enhanced 2.2-fold by IPTG induction at a mid-exponential growth phase. Among organic solvents with different log P values, isooctane was chosen based on the high activity and the enantioselectivity of McEH. Some lyoprotectants such as skim milk or sucrose enhanced the McEH activity. Enantiopure (S)-Styrene oxide with a 98% ee was obtained from the racemic styrene oxide with a 53.6% yield based on its theoretical yield in isooctane.

Batch Production of Chiral Epichlorohydrin by Enantioselective Hydrolysis Reaction using Rhodosporidium toruloides (Phodosporidium toruloides의 광학선택적 가수분해활성을 이용한 Chiral Epichlorohydrin의 회분식 생산)

  • 이은열;이재화
    • KSBB Journal
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    • v.19 no.1
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    • pp.38-41
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    • 2004
  • Enantioselective hydrolysis for the producing chiral epichlorohydrin from its racemic substrate was investigated using epoxide hydrolase activity of Rhodosporidium toruloides SJ-4. The effects of reaction parameters including pH, temperature, initial substrate concentration on initial hydrolysis rate and enantioselectivity were analyzed and optimized. The addition of detergent, Tween 20, enhanced the hydrolysis rate and enantioselectivity. Chiral (R)-epichlorohydrin with high optical purity (>99% ee) and yield of 25% (theoretically 50% maximum yield) was obtained from its racemate of 20 mM.

Optimization of Epoxide Hydrolase-Catalyzed Enantioselective Hydrolysis of Racemic Styrene Oxide (Rhodotorula sp. CL-83 유래의 에폭사이드 가수분해효소를 이용한 라세믹 Styrene Oxide 입체특이성 가수분해 조건 최적화)

  • 이은열
    • Journal of Life Science
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    • v.12 no.6
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    • pp.765-768
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    • 2002
  • Enantioselective hydrolysis of racemic styrene oxide by Rhodotorula sp. CL-82 was investigated. Reaction conditions including pH, temperature, and volume ratio of organic cosolvent were optimized using response surface methodology, and the optimal conditions of pH, temperature, and the volume ratio of cosolvent were determined to be 7.64, $33.26^{\circ}C$, and 3.09 %(v/v), respectively. Chiral (S)-phenyl oxirane could be obtained with high enantiomeric purity (ee > 99%) and 20% yield (theoretical yield = 50%) at the optimal rendition.

Production of Chiral Styrene Oxide by Microbial Enantioselective Hydrolysis Reaction (미생물 입체선택성 가수분해 반응을 이용한 광학활성 Styrene Oxide 생산)

  • 윤성준;이은열
    • KSBB Journal
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    • v.15 no.6
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    • pp.630-634
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    • 2000
  • Chiral epoxides are useful chiral synthons in organic synthesis, and various biological methods have been investigated for their production. In this work, the enantioselective resolution of racemic styrene oxide was investigated using Aspergillus niger sp. for the production of optically pure (S)-styrene oxide. The enantioselectivity and initial hydrolysis rates of the racemic substrate were highly dependent of the pH, temperature, and the volume ratio of cosolvent. Experimental sets of pH, temperature, and the volume ratio of cosolvent were investigated using a central composite experimental design, and reaction conditions were optimized by response surface analysis. The optimal conditions of pH, temperature, and the volume ratio of cosolvent were determined to be 7.78, $28.32^{\circ}C$, and 2.4%(v/v), respectively, and optically pure (S)-styrene oxide (>99% ee) was obtained at 35% yield using this microbial enantioselective hydrolysis reaction.

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Enantioselective Hydrolysis for the Precursor of Azole-containing Compounds using Acinetobacter sp. SY-01 Lipase and Increase of Enantioselectivity by the Removal of Reaction Products (Acinetobacter sp. SY-01 Lipase를 이용한 아졸계 화합물 전구체에 대한 광학선택적 가수분해 반응과 생성물 제거에 의한 광학선택성 증가)

  • 윤문영;신평균;정찬성;박정극
    • KSBB Journal
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    • v.18 no.1
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    • pp.1-7
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    • 2003
  • Screening of a strain was carried out to produce an enantioselective lipase toward the precursor of ltraconazole as azole-containg compounds, which are well known as antifungal drug agents. An Acinetobacter sp. SY-01 strain which can selectively hydrolyze the racemic substrates was isolated and the racemic substrate was resolved to the S-ester in 95.6% enantiomeric excess after 74.8% hydrolysis. The optimum temperature and pH for the conversion were $50^{\circ}C$, pH 7.0. However, the temperature and pH had no effect on the enantiomeric excess. Addition of solvents decreased the conversion and slightly increased the enantiomeric excess. However, the kind of solvents had no effect on enantiomeric excess. The substrate concentration decrease enantiomeric excess and this is confirmed by the products generated from hydrolysis, and also enantiomeric excess could be increased by the removal of reaction products.

Epoxide Hydrolase-catalyzed Hydrolytic Kinetic Resolution for the Production of Chiral Epoxides (에폭사이드 가수분해효소에 의한 동력학적 가수분해반응을 이용한 광학활성 에폭사이드 생산)

  • 이은열
    • KSBB Journal
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    • v.17 no.4
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    • pp.321-325
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    • 2002
  • Chiral epoxides are valuable intermediates for the asymmetric synthesis of enantiopure bioactive compounds. Microbial epoxide hydrolases (EHs) are newly discovered enzymes and versatile biocatalysts for the preparation of chiral epoxides by enantioselective hydrolysis of cheap and easily available racemic epoxide substrates. EHs are commercially potential biocatalysts due to their characteristics such as high enantioselectivity, cofactor-independent catalysis, and easy-to-Prepare catalysts. In this Paper, recent progresses in biochemistry and molecular biology of EH and developments of novel reaction systems are reviewed to evaluate the commercial feasibility of EH-catalyzed hydrolytic kinetic resolution for the production of chiral epoxides.

Studies on the Enzymatic Partial Hydrolysis of Soybean Protein Isolates (효소처리에 의한 분리대두 단백질의 부분 가수분해에 관한 연구)

  • Lee, Cherl-Ho;Kim, Chan-Shick;Lee, Sam-Pin
    • Korean Journal of Food Science and Technology
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    • v.16 no.2
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    • pp.228-234
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    • 1984
  • A partial hydrolysis of soybean protein isolate was carried out by using pepsin and trypsin. The degree of hydrolysis was evaluated by chemical analysis, viscometric measurements and gel electrophoresis. The functional properties of the hydrolyzates such as flow behavior, emulsion properties and foaming properties were evaluated. A selective hydrolysis of 11S protein fraction by pepsin was observed from the SDS-PAG electrophoresis. The changes in the molecular weight distribution by different conditions of enzyme hydrolysis were evaluated. The changes in the intrinsic viscosity of the protein hydrolylate by reaction time were highly correlated to the contents of TCA soluble protein and 0.03 M $CaCl_2$ soluble nitrogen. The degree of hydrolysis ($DH_{TCA}$, $DH_{Ca}$) were used to evaluate the effect of enzyme treatment on the functional properties of the hydrolyzate. The apparent viscosity and emulsion capacity and stability of the protein solution decreased as DH increased, while the foaming capacity increased linearly with the increasing DH.

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ACE 억제작용성 고혈압 강하제 개발

  • 김동한;고차원
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 1994.04a
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    • pp.214-214
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    • 1994
  • 본 실험실에서 개발한 대표적인 함아연 가수분해 효소인 carboxypeptidase A에 선택적으로 작용하는 mechanism-based inactivator의 설계법을 ACE 억제제 개발에 적용하여 고혈 압강하효과가 있을 것으로 기대되는 새로운 형태의 ACE 억제제들을 합성하였다. 그 대표적인 합성경로는 아래와 같다. (Figure Omitted)

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UV Spectrometric Assay of Epoxide Hydrolase Activity of Microbial Cell Biocatalysts (자외선분광기를 이용한 미생물 세포 생촉매의 에폭사이드 가수분해효소 활성평가)

  • Kim, Hee Sook;Lee, Eun Yeol
    • Applied Chemistry for Engineering
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    • v.16 no.3
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    • pp.456-459
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    • 2005
  • UV spectrometric assay for measurement of epoxide hydrolase activity was tested for efficient screening of whole cell activity of epoxide hydrolase. Epoxide hydrolase activities were determined by measuring the amount of p-nitrostyrene diol (pNSD), which was the hydrolysis product of p-nitrostyrene oxide (pNSO). Enantioselective hydrolysis of racemic pNSO using epoxide hydrolase activity of Rhodosporidium toruloides was monitored by UV spectrometric assay, and the relevant $K_m$ and $V_m$ for R. toruloides were determined as $2.457nmol/min{\cdot}mg$ and 1.078 mM, respectively.