• KSBB Journal
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• 제15권3호
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• pp.313-317
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• 2000

In this paper enantioselective production of levofloxacin by porcine liver esterase was investigated, To enhance the produc0-tivity various factors which affect the enzyme activity and the enantioselectivity were optimized, In terms of temperature and pH 45$^{\circ}C$ and 4.8 were found to be the best conditions for enzyme reaction. Addition of ofloxacin butyl ester the substrate at the concentration of 5 g/L was desirable to avoid the product inhibition and the activity of porcine liver esterase was maintained up to 72 hours.In addition to enhance the availability of substrate effect of solvent was also examined. It was found that the application of 5% (v/v) of acetone acetonitrile and dimethylsulfoxide did not increase the conversion of substrate and the presence of 5%(v/v) butanol inhibited the enzyme activity significantly.

• Journal of Microbiology and Biotechnology
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• 제24권9호
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• pp.1260-1268
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• 2014

Screening of a gene library from Paenibacillus sp. PBS-2 generated in Escherichia coli led to the identification of a clone with lipolytic activity. Sequence analysis showed an open reading frame encoding a polypeptide of 378 amino acid residues with a predicted molecular mass of 42 kDa. The esterase displayed 69% and 42% identity with the putative ${\beta}$-lactamases from Paenibacillus sp. JDR-2 and Clostridium sp. BNL1100, respectively. The esterase contained a Ser-x-x-Lys motif that is conserved among all ${\beta}$-lactamases found to date. The protein PBS-2 was produced in both soluble and insoluble forms when E. coli cells harboring the gene were cultured at $18^{\circ}C$. The enzyme is a serine protein and was active against p-nitrophenyl esters of $C_2$, $C_4$, $C_8$, and $C_{10}$. The optimum pH and temperature for enzyme activity were pH 9.0 and $30^{\circ}C$, respectively. Relative activity of 55% remained at up to $5^{\circ}C$ with an activation energy of 5.84 kcal/mol, which indicates that the enzyme is cold-adapted. Enzyme activity was inhibited by $Cd^{2+}$, $Cu^{2+}$, and $Hg^{2+}$ ions. As expected for a serine esterase, activity was inhibited by phenylmethylsulfonyl fluoride. The enzyme was remarkably active and stable in the presence of commercial detergents and organic solvents. This cold-adapted esterase has potential as a biocatalyst and detergent additive for use at low temperatures.

• The Korean Journal of Ecology
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• 제21권6호
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• pp.771-777
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• 1998

Aqueous extracts of Pinus rigida changed the electrophoretic patterns of total proteins and of hydrolytic enzymes such as peroxidase, esterase and amylase during the germination of radish (Raphanus sativus var. hortensis for. acanthiformis). When the extract treatment was finished, at the late stage of radish germination, aqueous extracts of P. rigida had suppressed the expression of 24 KD and 60 KD proteins. the extract induced new isozyme bands, indicating concomitant activity of peroxidases, esterase activities were stimulated in the cathodic region. The activity of amylase was enhanced by the extract.

• 미생물학회지
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• 제55권2호
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• pp.143-148
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• 2019

라세믹체 형태의 전구물질 methyl DL-${\beta}$-acetylthioisobutyrate (DL-ester)로부터 captopril 합성과정의 중간물질로 알려져 있는 D-${\beta}$-acetylthioisobutyric acid (DAT)를 효율적으로 제조하기 위해 광학선택적 esterase활성을 가진 신규 미생물을 탐색하였고 활성이 우수한 균주 CJ-317과 균주 CJ-187을 선별하고 동정한 결과, 각각 Klebsiella pneumoniae와 Pseudomonas putida로 동정하였다. 두 균주가 생산하는 esterase의 최적 반응온도와 내열성을 조사한 결과, P. putida CJ-187와 K. pneumoniae CJ-317의 최적활성은 각각 $60^{\circ}C$와 $75^{\circ}C$이었으며 또한 P. putida CJ-187의 경우, $60^{\circ}C$까지 안정한 반면 K. pneumoniae CJ-317은 $80^{\circ}C$에서도 1시간 동안 안정된 내열성 효소의 특성을 보였다. DAT에 의한 최종 산물의 활성 저해도에 있어서도 P. putida CJ-187은 2.5%와 5%의 DAT에 대해 각각 55%와 80%의 저해활성을 보인 반면 K. pneumoniae CJ-317는 각각 35%와 44%의 낮은 저해활성을 보임으로서 K. pneumoniae CJ-317은 captopril 합성의 중간체인 DAT 제조과정에 유용하게 활용할 수 있는 우수한 내열성 광학선택적 esterase 활성을 가지는 신규 균주임을 확인하였다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.445-448
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• 2002

The Pseudomonas fluorescens KCTC 1767, a selected and identified as potential candidate for stereo-specific resolution of rac-ketoprofen ethyl ester, was systematically investigated in order to induce the high level expression and detailed characterization of the expressing enzyme esterase. We cloned the esterase gene from chromosomal DNA of Pseudomonas fluorescens KCTC 1767 by PCR with two synthetic primers that desinged for simple purification. The recombinant esterase from Pseudomonas fluorescens KCTC 1767 exibited a high conversion rate and enantioselectivity to the (S)-ketoprofen ethyl ester as expected. The enzyme was easily purified to homogeniety by using a metal chelating affinity chromatography as a protein with poly histidine taq, and thus obtained 0.6 mg of protein from a 100 mL culture broth in a single step. The purified enzyme was steadily stable at the pH range from 7.0 to 10. The activity was also retained to be about 70% after the preincubation at $40^{\circ}C$ but over $50^{\circ}C$ lost the activity completely. The molecular mass of the esterase was estimated to be about 43 kDa on SDS-PAGE, and an identical result was also shown in gel filteration chromatography. The specific activity was calculated 27 mM/mg-protein/min by using the rac-ketoprofen ethly ester as a substrate.

• 한국응용곤충학회지
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• 제26권3호
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• pp.165-170
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• 1987

본(本) 실험(實驗)은 벼멸구에 대한 반수치사약량(半數致死藥量)의 차이(差異)를 나타내는 저항성(抵抗性) 및 감수성계통(感受性系統)과 그들의 교잡종(交雜種) $F_1$에 대(對)한 생화학적(生化學的) 특성(特性)을 구명(究明)하고자 실시(實施)하였다. 살충제무처리(殺蟲劑無處理)의 esterase활성(活性)은 저항성계통(抵抗性系統)과 교잡종(交雜種) $F_1$이 감수성계통(感受性系統)에 비(比)하여 높았으며, diazinon, MEP, BPMC 처리후(處理後) esterase의 활성변화(活性變化)는 저항성계통(抵抗性系統)과 교잡종(交雜種) $F_1$에서는 별차이(別差異)가 없었으나 감수성계통(感受性系統)에서는 현저(顯著)히 떨어졌다. Esterase의 높은 활성(活性)은 저항성발달(抵抗性發達)과 관계(關係)가 있었으며 교잡종(交雜種) $F_1$에서 esterase 활성(活性)이 높게 나타난 것은 저항성계통(抵抗性系統)이 우성인자(優性因子)로 유전(遺傳)됨을 알 수 있었다.

• 한국동물학회지
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• 제31권3호
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• pp.225-235
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• 1988

spirometra ernacei의 제3기 유충 plerocercoid(sparganum)를 중간숙주인 흰쥐와 종숙주인 고양이에게 감염시켜서 회수한 sparganum과 성충의 non-specific esterase와 acid,alkaline phosphatased의 분포 및 isozyme pattern 변화를 비교하기 위하여 효소조직화학적 방법과 전기영동법을 이용하여 다음과 같은 결과를 얻었다. 첫째,non-specific esterase는 sparganum과 성체의 근층과 유조직층에 많이 분포하였고 표피층에는 거의 분포가 없었다. 이의 isozyme band pattern은 sparganum에서 7개의 성체에서 8개의 isozyme band로 분리 되었는데 sparganum과 성체의 major band는 각각 3번과 4번 band였다. 둘째,acid phosphatse는 sparganum과 성체의 표피층과 근층에서 많이 부포하였고 유조직층에는 거의 분포가 없었다. isozyme band pattern은 sparganum과 성체에서 각각 3개의 band로 분리되었는데 3번 band가 major band였다.셋째, alkaline phoosphatase는 sparganum과 성체의 표피층과 근층에서 많은 분포를 보였으며 유조직층에서 더 상당한 분포가 있었다. isozyme band pattern은 sparganum에서 2개 성체에서 4개가 분리되었는데 sparganum성체 모두 2번 band가 major band였다.

• Journal of Microbiology and Biotechnology
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• 제24권6호
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• pp.771-780
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• 2014

A putative lipolytic enzyme gene, named as est9x, was obtained from a marine microbial metagenome of the South China Sea. Sequence analysis showed that Est9X shares lower than 27% sequence identities with the characterized lipolytic enzymes, but possesses a catalytic triad highly conserved in lipolytic enzymes of the ${\alpha}/{\beta}$ hydrolase superfamily. By phylogenetic tree construction, Est9X was grouped into a new lipase/esterase family. To understand Est9X protein in depth, it was recombinantly expressed, purified, and biochemically characterized. Within potential hydrolytic activities, only lipase/esterase activity was detected for Est9X, confirming its identity as a lipolytic enzyme. When using p-nitrophenol esters with varying lengths of fatty acid as substrates, Est9X exhibited the highest activity to the C2 substrate, indicating it is an esterase. The optimal activity of Est9X occurred at a temperature of $65^{\cric}C$, and Est9X was pretty stable below the optimum temperature. Distinguished from other salt-tolerant esterases, Est9X's activity was tolerant to and even promoted by as high as 4 M NaCl. Our results imply that Est9X is a unique esterase and could be a potential candidate for industrial application under extreme conditions.

• 한국식품영양과학회지
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• 제28권4호
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• pp.816-821
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• 1999

Cholesterol esterase(pCEH, pancreas cholesterol ester hydrolase, E.C.3.1.1.13) which is secreted from pancreas has been known as an important lipase for cholesterol uptake. cholesteryl acyl esters from a diet must be hydrolyzed to free cholesterol and fatty acid by cholesterol esterase before the absorption in small intestine. For the development of inhibitory substances from natural source, we screened many extracts of oriental herbs for the inhibition of cholesterol esterase in vitro. The ethanol extract of Ephedra herba showed strong inhibitory activity. Solvent fractionation and silica gel column chromatography with the extract lead to the purification of the inhibitory principle in Ephedra herba. Crystallized inhibitor was identified as ( ) ephedrine by using UV, FT IR, 1H NMR, 13C NMR and GC/Mass. These results suggest that ( ) ephedrine can be used as a potential lead compound for the development of inhibitor for cholesterol uptake by cholesterol esterase inhibition.

• Archives of Pharmacal Research
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• 제21권1호
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• pp.41-45
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• 1998

Hypericin, a photosensitizing plant pigment, was found to be a potent inducer of differentiation of human myeloid leukemia U-937 cells. At a concentration of $0.2{\mu}M$, hypericin exhibited 50% growth inhibition. An effect on cell differentiation by hypericin was assessed by its ability to induce phagocytosis of latex particles, and to reduce nitroblue tetrazolium (NBT). Approximately 51% of $0.2{\mu}M$ hypericin-treated cells were stained with NBT and 63% showed phagocytic activity. In order to establish whether hypericin induces differentiation of U-937 cells to macrophage or granulocyte, esterase activities and cell sizes were measured. When U-937 cells were treated with $0.2{\mu}M$ and $0.15{\mu}M$ of hypericin, the .alpha.-naphthyl acetate esterase activity was increased by 38.4% and 48.1%, respectively, but naphthol AS-D chloroacetate esterase activity was not influenced. The size of hypericin-treated cells in terms of cell mass was larger than that observed in untreated cells as determined by flow cytometry. Protein kinase C (PKC) inhibitor, NA-382, decreased the NBT reducing activity of hypericin, whereas a cAMP-dependent protein kinase A (PKA) inhibitor, H-89, did not show any influence on the differentiations. These results indicate that hypericin triggers differentiation toward monocyte/macrophage lineage by PKC stimulation.