• Korean Journal of Food Science and Technology
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• v.16 no.1
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• pp.41-46
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• 1984

The pectic enzymes produced from Aspergillus niger were separated into three fractions (F-A, F-I and F-II) by means of Sephadex and DEAF-Sephadex column chromatography. Each enzyme fraction was characterized by determining viscosity change and reducing surgar of the pectic acid-enzyme mixture and analyzing thin layer chromatogram of the reaction products. F-I rapidly reduced the viscosity of pectic acid solution and released reducing groups in a random manner so that appeared to be an endo-polygalacturonase (endo-PG). The optimum pH of endo-PG for viscosity reducing activity was 4.2 and that for releasing reducing surgar was 4.7. In the thermal inactivation of endo-PG of $30-45^{\circ}C$, the enthalpy of activation was 217.3 kj/mole and z-value was $7.5^{\circ}C$. F-II and F-A were determined as endo-polymethylgalacturonase and exo-polygalacturonase, respectively.

• Journal of Microbiology and Biotechnology
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• v.14 no.2
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• pp.297-301
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• 2004

The dTDP-D-glucose 4,6-dehydratase from Salmonella enterica was immobilized using covalent binding to cyanogen bromide activated sepharose. The immobilized enzyme was used to produce dTDP-4-keto-6-deoxy-D-glucose, a key sugar intermediate that can be used economically to produce diverse classes of unusual sugars appended in various antibiotics. The enzyme was immobilized on the sepharose after activation with cyanogen bromide. The maximum immobilization (80.03％) was achieved after 14 h of coupling. The covalently immobilized enzyme was stable, and an average of 78.4 ％ conversion was achieved until 120 h of immobilization when it was repeatedly used. Similar conversion was noticed for the first batch using the enzyme entrapped-hydrogel but activity was gradually decreased in the following batches. The production of dTDP-4-keto-6-deoxy-D-glucose by using an immobilized enzyme has high potential for commercial application.

• Journal of Life Science
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• v.6 no.3
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• pp.198-203
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• 1996

A thermolabile alkaline phosphatase has been purified through steps of osmotic shock, ammonium sulfate salting-out, and DAEA-cellulose chromatography from the cultured broth of the marine Vibrio sp. M-96 strain. The optimal temperature for the enzyme activity was 35$\circ$C. The optimal pH was pH11.0, and the range of pHstability was pH10.4 to 12.0. Thermal inactivation occured within 6 mintes at 60$\circ$C. The enzyme was considerably inactivated by 0.1mM concentrations of Hg$^{2+}$, Ni$^{2+}$ and Zn$^{2+}$, whereas activated up to 234% by 1mM of Mn$^{2+}$. The activation energy and deactivation energy by the Arrhenius equation were 4.02 Kcal/mol and 9.098 Kcal/mol, respectively. The Km and Vmax values of the enzyme for p-introphenylphosphate were found to be 0.0465mM and 0.001334mM/min, respectively. Active form of the enzyme had a molecular weight of 57,000 dalton determined by the Sephadex G-200 gel filtration method.

• YAKHAK HOEJI
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• v.29 no.4
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• pp.165-175
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• 1985

It has been reported that clonidine is $\alpha_2$-adrenergic agonist, potnet new hypotensive drug in human with low dose. The change in blood pressure is implicated in the concentration, release, uptake and metabalism of catecholamine and activity of catecholamine synthesizing enzyme in specific brain areas. Thus the experiment was set up to investigate the effect on the enzyme activity of clonidine alone and that of clonidine pretreated with imipramine or tranylcypromine by measuring activity of the Dopa-forming enzyme, tyrosine hydroxylase (TH) and epinephrine forming enzyme, phenylethanolamine-N-methyl transferase (PNMT) in brain and adrenal gland. The TH activity in brainstem and substantia nigra is decreased by intraperitoneally administered clonidine 0.1mg/kg twice a day for 5 days, but increased in the rats pretreated with imipramine 10mg/kg intraperitoneally given 26 hrs and 5 hrs before decaptitation. However the TH activity in all regions of brain is increased in rats pretreated with tranylcypromine 10mg/kg intraperitoneally twice a day for 5 days. The effect of clonidine on TH activity is due to inhibition release of norepinephrine by activation of presynaptic $\alpha_2$-adrenoreceptor, axon terminal result in the decrease of TH activity in brain. The increasing of TH activity in brain results in attenuation of the role of clonidine by pretreated with imipramine or tranylcypromine in rats. The activity of PNMT was not significantly affected by clonidine, imipramine and tranylcypromine in adrenal gland.

• Journal of Environmental Health Sciences
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• v.19 no.3
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• pp.58-63
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• 1993

In order to elucidate the alteration of drug-metabolizing enzymes and mechanism in the animal with hepatic injury and ketosis, the regulation of P450IIE was studied in the rats with heaptic injury caused by CCl$_4$ and with ketosis caused by streptozotocin and high-fat diet. P450IIE expression in liver was examined by the combination of enzyme activities, Western immunoblot, and mRNA Northern blot analyses using specific polyclonal antibody and cDNA probe for P450IIE. Enzyme activity and amounts of immunoreactive P450IIE were rapidly decreased in a time-dependent manner after a single dose of CCl$_4$ . However, the decreases in P450IIE enzyme activity and immunoreactive protein by CCl$_4$ were not accompanied by a decline in its mRNA level. The data thus suggested a post-translational reduction of P450IIE by CCl$_4$. The enzyme activities (aniline hydroxylase) in hepatic microsomes were elevated about 2-3-fold by streptozotocin and feeding with a high fat diet. This increases in enzyme activities were also accompanied by 3-fold increases in immunoreactive P450IIE protein and its mRNA. Our data thus indicated that P450IIE induction during the ketosis appears to be due to pretranslational activation.

• Applied Biological Chemistry
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• v.26 no.4
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• pp.217-221
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• 1983

$\beta$-Galactosidase($\beta$-D-galactoside galactohydrolase, E.C. 3. 2. 1. 23) from E. coli K-12 CSH 36 was immobilized on porous cellulose beads which were previously activated with tannin and p-benzoquinone. Their general properties and applicational possibities were investigated. The most effective, enzyme immobilization was obtained when tannin and p-benzoquinone, pH 11.0, were used together as activation reagents and a period of 6 hours of activation. The optimum pH of $\beta$-galactosidase was 5.5 for free enzyme and 6. 0 for the immobilized enzyme, the optimum temperatures for native and immobilized enzyme were both $50^{\circ}C$. Kms of native $\beta$-galactosidase and immobilized enzyme for ONPG(o-nitrophenyl galactopyranoside) were about $4.0{\times}10^(-4)M$ and $7.5{\times}10^(-4)M$, respectively. In the case of tannin : p-benzoquinone activated cellulose beads, the immobilized enzyme retained over 80% of the initial enzyme activity after 20 runs, which is very promising result far a possible industrial application.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.523.1-523
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• 1986

To extend the spectrum of enzyme utilization in the organic solvent system, C. rugosal lipase was selected as a model enzyme because its substrate is soluble to organic solvent. One of the serious disadvantages in this system was the deactivation of the lipase. The pattern of lipase deactivation was the biphasic model. The activation energies for the deactivation were 14.05${\times}$10$^4$ KJ/Kg mole in the first phase and 3.59 ${\times}$ 10$^4$ KJ/mole in the second phase. The several factors were studied for their influences on the pattern of deactivation. Iso-octane as organic solvent influenced more on the first phase than the second phase. Urea as the reagent affecting boty hydrophobic interaction and hydrogen bond of enzyme also influencea more on the first phase. And the optimum pH for the activity was not correlated to that of the stability.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.21 no.1
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• pp.1-10
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• 2015

Enzyme kinetics-based respiration model can be effectively used for estimating respiration rate in $O_2$ consumption and $CO_2$ production of fresh produce as a function of $O_2$ and $CO_2$ concentrations. Arrhenius equation can be applied to describe the temperature dependence of the respiration rate. Parameters of enzyme kinetics-based respiration model and activation energy of Arrhenius equation were compiled from analysis of literature data and closed system experiment. They enable to estimate the respiration rate for any modified atmosphere conditions at temperature of interest and thus can be used for design of modified atmosphere packaging of fresh produce.

• Proceedings of the Korean Society of Toxicology Conference
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• 2002.05a
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• pp.24-42
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• 2002

Antioxidant responsive element (ARE) mediates the transcriptional activation of the genes encoding phase II drug metabolizing enzymes and antioxidative stress genes. The ARE consensus sequence shows high similarity to NF-E2 binding sequence, a cisacting erythroid gene regulatory element.(omitted)

• Journal of environmental and Sanitary engineering
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• v.10 no.2
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• pp.74-78
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• 1995

Several reports have suggested that these hydrolases( chitlnase, glucanase ) are likely volved in defense reactions in this Plant. In this paper, Induction by ethylene, mechanism, properties and function for Activation of these enzymes were Summarized.