• 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.

• 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 The Korean Society of Grassland and Forage Science
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• v.11 no.4
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• pp.199-202
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• 1991

The esterase isozyme of several legume plants were separated and visualized by horizontal starch gel electrophoresis using enzyme-specific staining. Extracts used were prepared from fully expanded young leaf and stem of six legume species which were red clover(Trifolium Pretense L.), ladino clover(Trifolium repense L.), wild white clover(Trifolium repense L.), alfalfa(Medicage sativa L.), mimosoides(Cassia mimosoides var nomame Makino), and amoena(Vicia amoena Fisch). The number of band, Phenotype and staining intensity of esterase isozyme in leaf and stem varies depending on the plant species. However, there are little difference between leaf and stem esterase isozyme in same species except alfalfa. And in the leaf and stem of mimosoides and amoena showed not any esterase(Fig. 2). Among the examined plants, the highest staining intensity and the rapidest migrating esterase isozyme was Est 1.

• 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.

• Microbiology and Biotechnology Letters
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• v.23 no.4
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• pp.454-460
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• 1995

Acetylxylan esterase II was produced by Escherichia coli HB101 harboring the recombinant plasmid pKMG7 which contained the estII gene of Bacillus stearothermophilus. Optimal medium for the production of the acetylxylan esterase by E. coli HB101/pKMG7 was determined to contain 0.5% galactose, 1% yeast extract and 1% NaCl. The enzyme produced was purified to homogeneity using a combination of 20-50% ammonium sulfate precipitation, DEAE-Sepharose CL-6B chromatography and Sephacryl S-200 gel filtration. The temperature and pH optimum of the esterase were 45$\circ$C and pH 6, respectively. The essential amino acids for the esterase activity were found to be methionine, serine, and cysteine. Molecular weight of the esterase was determined to be 28 kDa by SDS-polyacrylamide gel electrophoresis, and 120 kDa by gel filtration. This suggests that the functional enzyme is a homomeric tetramer. The esterase had an isoelectric point of pH 3.4. The N-terminal amino acid sequence of the enzyme was Ala-Leu-Phe-Glu-Ser-Arg-Phe-Phe-Ser-Glu-Val-Leu-Gly-Leu.

• Microbiology and Biotechnology Letters
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• v.26 no.1
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• pp.50-54
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• 1998

Ethyl caproate is one of the important flavor compounds produced during the brewing of rice wine. The rice wine yeast and koji were reported to produce the esterases which synthesize and also hydrolyze ethyl caproate. From the results of monitoring the esterase activities of rice wine yeast and koji, their roles for producing ethyl caproate during brewing were postulated. In case of rice wine yeast, the production of esterase synthesizing ethyl caproate was influenced by the substrate, caproate but that of esterase hydrolyzing ethyl caproate was promoted by ethyl caproate but inhibited by caproate. The production of esterases of koji were not influenced by the substrates for ethyl caproate production but influenced by the growth of koji. The maximum concentration of ethyl caproate produced by rice wine yeast was 0.4 ppm in this research but the production of ethyl caproate by koji was not detected under our experimental conditions. Considering the results of this research, ethyl caproate is not produced by the esterases of koji during brewing but produced by the esterases of rice wine yeast. The growth of rice wine yeast represses that of koji because of the high concentration of ethanol produced by rice wine yeast. The esterases of rice wine yeast may decide the production of ethyl caproate during brewing.

• Journal of Sericultural and Entomological Science
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• v.21 no.1
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• pp.21-28
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• 1979

The Electrophoretic separation in agarose gel on the esterase and acid phosphatase of blood, midgut and silk gland was carried out with 2 original variginal varieties and 7 F$_1$ hybrids. 1. The midgut of larvae fed on mulberry leaves showed one or two more esterase bands than that of larvae fed on artificial diet. 2. The midgut of C 15 larvae being excellently respondent to artificial diet showed one or two more esterase bands than that of larvae being bad respondent to artificial diet. 3. Electrophoretic separation of esterase bands appeared to be greatly different among newly hatched larvae, 1st and 2nd install larvae of F$_1$hybrids. However the difference among the silkworm varieties was not recognized. 4. According to the change in rearing temperature, the number of the active band of midgut esterase was varied. At the temperature of 28$^{\circ}C$ 5 active esterase bands were found. At temperature of 35$^{\circ}C$ 4 bands were noted at 3rd install and 6 or 7 bands at 4th instar. 5. No similar esterase bands conld be found among midgut, blood and silkgland. There are five esterase bands in the midgut, one in blood and three in silkgland. 6. There was rather small difference in acid phosphatase types of midgut and blood according to varieties and rearing temperature. No active band was shown in silkgland. In midgut, there was one acid phosphatase band at 3rd install, two at 4th instar and three at 5th instar. In blood, One active band at 3rd or 4th instar and three bands at 5th inatar were detected.

• Korean journal of applied entomology
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• v.32 no.3
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• pp.265-270
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• 1993

The German cockroach(Blattelia germanica) population~ were successIVely selected with ch\orpyrifos and permethrin during the six generations. The resulting resistant $R_{chtorpenfos}$(Rc) and $R_{permethnn}$(Rp) stra.ins were studied to investigate the esterase activity by spectrophotometer, filter parper test, and electrophoresis. Esterase-$\alpha$ activities by filter paper test showed 2.65 and LBZ times higher in the Rc and Rp strains than the susceptible strain, respectively. ln the spectrophoLometer method, the esterase activit18s to $\alpha$-and $\beta$-naphthyl acetate were increased 2.34 and 5.28 times in the Rc than susceptible strain, and 1.48 and 2.92 times in the Rp Limn susceptible stram, respectlvely. Zymogram patterns of eslerase isozyme by agarose gel electrophoresis showed totally five bands. The Rc and Rp strains showed two additive bands as, Est-2 and Est-3, which were not shown in the susceptible strain. but the Rp strain dId not show Est-5 bands which was COlumon in the Rc and susceptible strams.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.4
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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.

• Microbiology and Biotechnology Letters
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• v.45 no.2
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• pp.149-154
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• 2017

To increase the efficiency of esterase production by Bacillus, high cell-density culture of recombinant Escherichia coli through fed batch fermentation was tested. Cells were cultured to $OD_{600}$ of 76 (35.8 g/l DCW) with dissolved oxygen level controlled to least above 30% air saturation by supplying pure oxygen. Cells were cultured to an $OD_{600}$ of 90 (42.4 g/l DCW) with glucose feeding controlled to at least 1 g/l. However, the cells reached stationary phase at the late stage of culture, despite glucose being supplied. Cells were cultured to an $OD_{600}$ of 185 (87.3 g/l DCW) by supplying additional medium with fortified yeast extract. To increase the productivity of the recombinant protein, cell growth and esterase productivity based on induction time were evaluated. Late exponential phase induction for esterase production in fed batch fermentation resulted in maximum optical density $OD_{600}$ of 190 (89 g/l DCW) and maximum esterase activity of 1745 U/l, corresponding to a 5.8-fold enhancement in esterase production, compared to the early exponential phase induction. In this study, we established fermentation methods for achieving maximum production of Bacillus-derived esterase by optimizing IPTG induction time in high-cell density culture by supplying pure oxygen and a nitrogen source.