• Title/Summary/Keyword: enantioselectivity

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Optimization of the Reaction Conditions and the Effect of Surfactants on the Kinetic Resolution of [R,S]-Naoroxen 2,2,2-Trifluoroethyl Thioester by Using Lipse (리파아제를 이용한 라세믹 나프록센 2,2,2-트리플로로에틸 씨오에스터의 Kinetic Resolution에서 반응조건 죄적화와 계면활성제 영향)

  • Song, Yoon-Seok;Lee, Jung-Ho;Cho, Sang-Won;Kang, Seong-Woo;Kim, Seung-Wook
    • KSBB Journal
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    • v.23 no.3
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    • pp.257-262
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    • 2008
  • In this study, the reaction conditions for lipase-catalyzed resolution of racemic naproxen 2,2,2-trilfluoroethyl thioester were optimized, and the effect of surfactants was investigated. Among the organic solvents tested, the isooctane showed the highest conversion (92.19%) in a hydrolytic reaction of (S)-naproxen 2,2,2-trifluoroethyl thioester. In addition, the isooctane induced the highest initial reaction rate of (S)-naproxen 2,2,2-trifluoroethyl thioester ($V_s=2.34{\times}10^{-2}mM/h$), the highest enantioselectivity (E = 36.12) and the highest specific activity ($V_s/(E_t)=7.80{\times}10^{-4}mmol/h{\cdot}g$) of lipase. Furthermore, reaction conditions such as temperature, concentration of the substrate and enzyme, and agitation speed were optimized using response surface methodology (RSM), and the statistical analysis indicated that the optimal conditions were $48.2^{\circ}C$, 3.51 mM, 30.11 mg/mL and 180 rpm, respectively. When the optimal reaction conditions were used, the conversion of (S)-naproxen 2,2,2-trifluoroethyl thioester was 96.5%, which is similar to the conversion (94.6%) that was predicted by the model. After optimization of reaction conditions, the initial reaction rate, lipase specific activity and conversion of (S)-naproxen 2,2,2-trifluoroethyl thioester increased by approximately 19.54%, 19.12% and 4.05%, respectively. The effect of surfactants such as Triton X-100 and NP-10 was also studied and NP-10 showed the highest conversion (89.43%), final reaction rate of (S)-naproxen 2,2,2-trifluoroethyl thioester ($V_s=1.175{\times}10^{-2}mM/h$) and enantioselectivity (E = 59.24) of lipase.

Mesoporous Silica-Carbon Composite Membranes for Simultaneous Hydrolysis and Separation of Chiral Epoxide (카본/메조세공 실리카 복합 막을 응용한 키랄 에폭사이드의 가수분해반응과 동시 분리)

  • Choi, Seong Dae;Jeon, Sang Kwon;Park, Geun Woo;Yang, Jin Young;Kim, Geon-Joong
    • Applied Chemistry for Engineering
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    • v.25 no.5
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    • pp.503-509
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    • 2014
  • The carbon/porous silica composite membrane was fabricated in a simple manner, which could be successfully for the simultaneous separation and production of chiral epoxides and 1,2-diols, based on their differences in hydrophilic/hydrophobic natures. The chiral Co(III)-$BF_3$ salen catalyst adopted in the membrane reactor system has given the very high enantioselectivity and recyclability in hydrolysis of terminal epoxides such as ECH, 1,2-EB, and SO. The optically pure epoxide and the chiral catalyst were collected in the organic phase after hydrolysis reaction. The hydrophilic water-soluble 1,2-diol product hydrolyzed by chiral salen diffused into the aqueous phase through the SBA-16 or NaY/SBA-16 silica composite layer during the reaction. The water acted simultaneously as a reactant and a solvent in the membrane system. One optical isomer was obtained with high purity and yield, and furthermore the catalysts could be recycled without observable loss in their activity in the continuous flow-type membrane reactor.

Production of Enantioselective Lipase from Acinetobacter sp. SY-01 (Acinetobacter sp. SY-01로부터 Enantioselective Lipase의 생산)

  • 박대원;박호일;신평균
    • Microbiology and Biotechnology Letters
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    • v.31 no.2
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    • pp.145-150
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    • 2003
  • Lipase from Acinetobacter sp. SY-01 plays an important role enzyme that products chiral drug. We investigated optimum condition for mass production of Acinetobacter sp. SY-01 lipase. Addition of among the different oils to medium. olive oil was optimal for enzyme production. When 0.2% olive oil was added as a carbon source, the production of lipase was increased to a maximum. The optimum pH and temperature were pH 7 and $30^{\circ}C$. In the presence of $Fe^{2+}$ and $Ca^{2+}$, the lipase activity was dramatically enhanced by 280% and 160%, respectively. SY-01 lipase was stable in the most of the DMSO among organic solvents. The addition of triton-X 100 increased the SY-01 lipase by 100-fold. The optimum composition of medium for production of the enzyme was 0.8% yeast extract, 0.2% olive oil, 0.4% triton X-100+40% DMSO. 0.1% $NH_4Cl$, 0.4% $K_2HPO_4$ 3.9% $NaH_2PO_4$, 0.03% $CaCl_22H_2O$, 0.01% $FeSO_4$$7H_2O$(pH 7.0).

Synthesis of Enantiopure Epoxide Compounds Using Dimeric Chiral Salen Catalyst (이량체구조를 갖는 키랄 살렌 촉매를 이용한 고 광학순도의 에폭사이드 화합물 합성)

  • Kim, Geon-Joong;Kim, Seong-Jin;Li, Wenji;Chen, Shu-Wei;Shin, Chang-Kyo;Thakur, Santosh S.
    • Korean Chemical Engineering Research
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    • v.43 no.6
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    • pp.647-661
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    • 2005
  • The stereoselective synthesis of chiral terminal epoxide is of immense academic and industrial interest due to their utility as versatile starting materials as well as chiral intermediates. In this review, we investigate the research and development trend in the asymmetric ring opening reactions using cobalt salen catalysts. Hydrolytic kinetic resolution (HKR) technology is the very prominent way to prepare optically pure terminal epoxides among available methods. We have synthesized homogeneous and heterogeneous chiral dinuclear salen complexes and demonstrated their catalytic activity and selectivity for the asymmetric ring opening of terminal epoxides with variety of nucleophiles and for asymmetric cyclization to prepare optically pure terminal epoxides in one step. The resolved ring opened product combined with ring closing in the presence of base and catalyst afforded the enantioriched terminal epoxides in quantitaive yield. Potentially, these catalysts are using on an industrial scale to produce chiral intermediates. The experimental results of HKR technology applied to the synthesis of various chiral compounds are presented in this paper.

Characterization of a Psychrophilic Metagenome Esterase EM2L8 and Production of a Chiral Intermediate for Hyperlipemia Drug (메타게놈유래의 저온성 에스터라제 EM2L8의 효소적 특성과 이를 활용한 고지혈증 치료제 키랄소재의 생산)

  • Jung, Ji-Hye;Choi, Yun-Hee;Lee, Jung-Hyun;Kim, Hyung-Kwoun
    • Microbiology and Biotechnology Letters
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    • v.37 no.2
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    • pp.118-124
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    • 2009
  • Esterase EM2L8 gene isolated from deep sea sediment was expressed in Escherichia coli BL21 (DE3) and the esterase activity of the cell-free extract was assayed using p-nitrophenyl butyrate-spectrophotometric method. Its optimum temperature was $40-45^{\circ}C$ and 45% activity of the maximum activity was retained at $15^{\circ}C$. The activation energy at $15-45^{\circ}C$ was calculated to be 4.9 kcal/mol showing that esterase EM2L8 was a typical cold-adapted enzyme. Enzyme activity was maintained for 6 h and 4 weeks at $30^{\circ}C$ and $4^{\circ}C$, respectively. When each ethanol, methanol, and acetone was added to the reaction mixture to 15% concentration, enzyme activity was maintained. In the case of DMSO, enzyme activity was kept up to 40% concentration. (S)-4-Chloro-3-hydroxy butyric acid is a chiral intermediate for the synthesis of Atorvastatin, a hyperlipemia drug. When esterase EM2L8 (40 U) was added to buffer solution (1.2 mL, pH 9.0) containing ethyl-(R,S)-4-chloro-3-hydroxybutyrate (38 mM), it was hydrolyzed into 4-chloro-3-hydroxy butyric acid with a rate of $6.8\;{\mu}mole/h$. The enzyme hydrolyzed (S)-substrate more rapidly than (R)-substrate. When conversion yield was 80%, e.e.s value was 40%. When DMSO was added, hydrolysis rate increased to $10.4\;{\mu}mole/h$. The plots of conversion yield vs e.e.s in the presence or absence of DMSO were almost same, implying that the reaction enantioselectivity was not changed by the addition of DMSO. Taken together, esterase EM2L8 had high activity and stability at low temperatures as well as in various organic solvents/aqueous solutions. These properties suggested that it could be used as a biocatalyst in the synthesis of useful pharmaceuticals.