• Journal of the Korean Society of Tobacco Science
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• v.20 no.1
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• pp.80-86
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• 1998

Changes in activity and classification of esterase isozymes during the tire cycle or Plodia inteipunctella (Hiibner) were investigated by the native polyacrylamide gel electrophoresis. The stage specificity in esterase activity and isozyme pattern was observed throughout the larvalpupal-adult transformation. The activity esterase was highest at the 3-day old adult stage, and the lowest level at the prepupal stage. A total of 12 esterase bands were identified throughout the development, and the bands showing high enzyme activity was observed in the middle part of gel. Twelve esterases on the basis of inhibition by the three types of inhibitors (organophosphates, eserine sulfate and sulfhydryl reagents) were classified into three class, namely, carboxylesterase (CE), arylesterase (ArE) and cholinesterase (ChE), and these classes contained 7, 3 and 2 isozymes, respectively.

• The Korean Journal of Zoology
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• v.33 no.3
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• pp.330-336
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• 1990

Changes in esterase activity and zymogram pattern during development in Pieirs rapae L. were investigated and three esterases (E2, E6 and E11) from the late 5th instar larvae were purified. Esterase activity in whole body increased rapidly during 5th instar larval stages and reached a peak at the late 5th instar larval stage. The number and intensity of esterase band from whole body and midgut also showed a peak at the late 5th instar larval stage. Purification of esterase was performed using gel filtration on Sephadex G-lOO, ion-exchange chromatography on DEAE-trisacryl and preparative electrophoresis. The final purities of these enzymes were about 30 to 60-fold.

• Applied Biological Chemistry
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• v.40 no.6
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• pp.484-489
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• 1997

The characteristics of growth and esterase activity of bacterial strains isolated from acid hydrolysed soybean protein were examined. All the isolated strains having decomposition activity of p-hydroxybenzoic acid butyl ester and esterase producing activity were identified as Bacillus sp. by morphological and biochemical methods. The specific growth rates, esterase activities and p-hydroxybenzoic acid butyl ester decomposition activities of isolated strains were $0.844{\sim}1.213\;h^{-1}$, $21{\sim}222\;mU/ml$ and $5.4{\sim}8.1\;mU/ml$, respectively. In the fermentation of Bacillus sp. KB8 strain which had the highest esterase producing activity, growth, extracellular excretion and intracellular synthesis of esterase were inhibited by adding NaCl in the culture broth. Esterase producing activity gradually increased after late exponential growth phase, until maximum value of 420 mU/ml reached after 64 hours culture period. Esterase of Bacillus sp. KB8 strain was stable up to $50^{\circ}C$ for 30 minutes, but was inactivated by heating for 30 minutes at $70^{\circ}C$. The enzyme activity exponentially decreased during the incubation time at the temperatures of $60^{\circ}C$ and $65^{\circ}C$.

• BMB Reports
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• v.40 no.4
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• pp.588-594
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• 2007

A novel hot spring thermophile, Anoxybacillus gonensis A4 (A. gonensis A4) was investigated in terms of capability of tributyrin degradation and characterization of its thermostable esterase activity by the hydrolysis of p-nitrophenyl butyrate (PNPB). It was observed that A. gonensis A4 has an esterase with a molecular weight of 62 kDa. The extracellular crude preparation was characterized in terms of substrate specificity, pH and temperature optima and stability, kinetic parameters and inhibition/activation behaviour towards some chemicals and metal ions. Tributyrin agar assay showed that A. gonensis A4 secreted an esterase and $V_{max}$ and $K_m$ values of its activity were found to be 800 U/L and 176.5 ${\mu}M$, respectively in the presence of PNPB substrate. The optimum temperature and pH, for A. gonensis A4 esterase was $60-80^{\circ}C$ and 5.5, respectively. Although the enzyme activity was not significantly changed by incubating crude extract solution at $30-70^{\circ}C$ for 1 h, the enzyme activity was fully lost at $80^{\circ}C$ for same incubation period. The pH-stability profile showed that original crude esterase activity increased nearly 2-fold at pH 6.0. The effect of some chemicals on crude esterase activity indicated that A. gonensis A4 produce an esterase having serine residue in active site and -SH groups were essential for its activity.

• Korean Journal of Environmental Agriculture
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• v.9 no.2
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• pp.97-103
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• 1990

In order to determine the major biochemical degradation factors of the two organophosphorus insecticides, diazinon and dursban, the activities of monooxygenase(m. o.) and ${\alpha}$, ${\beta}-esterase$ were studied in submerged soil under laboratory conditions at $30{\pm}1^{\circ}C$ The degradation rate of diazinon by microorganism showed 1.5 times higher than dursban. The m. o. activity increased from 12hrs and 3days after application of diazinon and dursban, respectively. But the ${\beta}-esterase$ activity showed maximum at one day after application of dursban and $5{\sim}8$ days after diazinon application. Also, the ${\beta}-esterase$ activity was about 10 times higher than ${\alpha}-esterase$. Hence, it was concluded that the biological degradation of diazinon was mainly attributed to m. o. activity and the degradation of dursban to ${\beta}-esterase$ activity.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.1
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• pp.53-56
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• 2000

A thermostable esterase from the hyper thermophilic archaeon Sulfolobus solfataricus was partially purified 590-fold with $16.2\%$ recovery. The partially purified esterase had a specific activity of $29.5\;{\mu}mol\;min^{-1}mg^{-1}$ when the enzyme activity was determined using p-nitrophenyl butyrate as a substrate. The apparent molecular weight was about 100 kDa, while the optimum temperature and pH for esterase were $75^{\circ}C$ and 8.0, respectively. The enzyme showed high thermal stability and solvent tolerance in comparison to its mesophilic counterpart. The enzyme also showed chiral resolution activity for (S)-ibuprofen, indicating that S. solfataricus esterase can be used for the production of commercially important chiral drugs.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.4
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• pp.367-371
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• 2005

About 3,000 bacterial colonies with esterase activities were isolated from soil samples by enrichment culture and halo-size on Luria broth-tributyrin (LT) plates. The colonies were assayed for esterase activity in microtiter plates using enantiomerically pure (R)- and (S)-2-phenylbutyric acid resorufin ester (2PB-O-res) as substrates. Two enantioselective strains (JH2 and JH13) were selected by the ratio of initial rate of hydrolysis of enantiomerically pure (R)- and (S)-2-PB-O-res. When cell pellets were used, both strains showed high apparent enantioselectivity ($E_{app}>100$) for (R)-2PB-O-res and were identified as Exiguobacterium acetylicum. The JH13 strain showed high esterase activity on p-nitrophenyl acetate (pNPA), but showed low lipase activity on p-nitrophenyl palmitate (pNPP). The esterase was located in the soluble fraction of the cell extract. The crude intracellular enzyme preparation was stable at a pH range from 6.0 to 11.0.

• Korean Journal of Veterinary Research
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• v.4 no.1
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• pp.15-17
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• 1964

Scabby burley collected in Kyong Sang Nam Do fed to healthy dogs, age less than 2 years, old and determined the Choline-Esterase Activity in blood of dogs. The results obtained in this investigation are summarized as follows. 1. Choline-Esterase Activity in the blood of dogs fed Scabby barley has been decreased. 2. The poisionous component of the Scabby barley thought to be Anticholinesterase.

• The Korean Journal of Pesticide Science
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• v.11 no.2
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• pp.117-124
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• 2007

Esterase activity was observed after pesticides treatment in eggs of H. axyridis to select low toxicity pesticide. Egg esterases of H. axyridis were examined using an esterase substrate(${\alpha}$-naphthyl acetate). Three esterase isozymes were detected and the activities were inhibited by organophosphorus insecticide (Chlorpyrifos and Phenthoate), organochlorine insecticide(Methidation), triazole fungicide(Hexaconazole and Triflumizole), and pyrimidine fungicide(Nuarlmol). Fecundity and hatchability in adults and eggs of H. axyridis were examined on selected pesticides. Fecundity and hatchability were significantly reduced from H. axyridis adults and eggs treated with the pesticides and the fungicides showed strong inhibition of esterase isozymes activities. However, we also observed the pesticides and the fungicides showed low or non-inhibition of esterase isozymes activities affected on fecundity and hatchability in adults and eggs.

• Journal of Microbiology and Biotechnology
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• v.18 no.5
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• pp.889-896
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• 2008

A suitable simple model tested by experiments is required to address complex biological reactions like esterase synthesis by Saccharomyces cerevisiae. Such an approach might be the answer to a proper bioprocessing strategy. In this regard, a logistic model for esterase production from Saccharomyces cerevisiae has been developed, which predicts well the cell mass, the carbon source (glucose) consumption, and the esterase activity. The accuracy of the model has been statistically examined by using the Student's t-test. The parameter sensitivity analysis showed that all five parameters (${\mu}_m$, $K_a$, $X_m$, $Y_{x/s}$, and $Y_{p/x}$) have significant influence on the predicted values of esterase activity.