• Membrane Journal
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• v.8 no.3
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• pp.170-176
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• 1998

A study on the bioconversion of soluble starch to cyclodextrin(CD) homologue by CGTase was performed in the membrane-enzyme reactor equipped with a dead-end type membrane module. in the batch reactor, the total conversion of soluble starch to CD homologue was decreased rapidly from a maximum value of 45 % with increasing reaction time due to the product inhibition and breakdown of CD homologue to the reducing sugars. However, in the membrane-enzyme reactor, the total conversion of soluble starch was maintained at a constant value of 35 % throughout the reaction, since the membrane(MWCO = 10,000) promptly separated CD homologue from the reaction mixture. After the macdon for 24 hr in the membrane-enzyme reactor using a 10 % soluble starch solution, the cumulative production amount of CD homologue was about 3.7 kg/m$^2$ at the operating pressure of 2 atm.

• Journal of Sasang Constitutional Medicine
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• v.17 no.2
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• pp.64-73
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• 2005

1. Objectives The purpose of this study was to investigate the effects of the enzyme activity of Palmulgunja-tang with administered orally solution on cytochrome P450 isozyme 2. Methods This study was carried on through following methods. We treated the rat with the {3-naphthoflavone (${\beta}NF$) of 80mg/kg for 3 days i.p injection. Firstable, microsomal protein was separated and total intracellular protein test was done. Then GOT and GPT were measured and assay of cytochrome P450 IAI/2 enzyme activity was performed according to the method of EROD and MROD. (Ethoxyresorufin-O-deethylase(EROD) activity was used to measure cytochrome P450 lAI activity and methoxyresorufin O-demethylase(MROD) activity was used to measure cytochrome P450 lA2 activity. ) 3. Results and Conclusions 1) PGT recovered the liver damage on ${\beta}NF$ inducible CYP IAI/2 by pre-post and high-low condition. 2) At concentration of post-treated 50mg!kg of PGT, the inhibiting of $\betaNF$ metabolites to liver of rat cytochrome P450 lAl was inhibited by 53.0% respectively. 3) PGT showed 36.0% inhibition of ${\beta}NF$-induced lA2 activity at the concentration post-treated 50mg/kg.

• Journal of the Korean Chemical Society
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• v.42 no.3
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• pp.302-305
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• 1998

The high cholesterol level in the blood stream is the main cause for cardiovascular diseases. Despite considerable worldwide effort to reduce the blood cholesterol level, we still need a remarkable drug. For this reason, the inhibition of cholesterolesterase by synthetic porphyrin complexes was investigated. Some of the phenyl substituted porphyrins inhibited the enzyme and the inhibition constant was in the range of ${\mu}M$. The substituents on the phenyl group of tetraphenylporphyrin did not affect much on the inhibition constant.

• BMB Reports
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• v.30 no.5
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• pp.332-336
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• 1997

The stimulatory effects of leucine on the activities of two soluble forms of brain glutamate dehydrogenase isoproteins (GDH I and GDH II) have been studied at various conditions. There were significant differences between GDH I and GDH II in their sensitivities to the action of leucine. When the effects of varied leucine concentrations on GDH activities were studied in the direction of reductive amination of 2-oxoglutarate with NADPH as a coenzyme, a marked activation was observed for both isoproteins at leucine concentrations up to 10 mM, whereas both isoproteins showed activation to a lesser extent with NADH as a coenzyme. The stimulatory effects of leucine on GDH activities in the direction of the oxidative deamination of glutamate were also observed, but to a much lesser extent. Leucine relieved the inhibition of GDH I by GTP and this resulted in an increase in the apparent activation by leucine in the presence of GTP. 2-Oxoglutarate was found to give rise to high substrate inhibition and leucine significantly reduced the substrate inhibition in the presence of $200\;{\mu}M$ NADH. Thus, the effects of leucine might be composed of a direct effect on the enzyme together with a relief of high substrate inhibition.

• Journal of Microbiology and Biotechnology
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• v.13 no.6
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• pp.853-858
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• 2003

Helicobacter pylori specifically adhere to host cells through a number of putative receptors and ligands, mainly based on carbohydrate-protein interactions. Polysaccharide fractions isolated from the leaves of Artemisia capillaris showed different inhibitory activities against H. pylori adhesion by using hemagglutination assay. Among these fractions, an acidic polysaccharide fraction FlA showed highly effective inhibitory activity, and its minimum inhibition concentration was 0.63 mg/ml. The inhibition results by the hemagglutination assay were consistent with those obtained by the enzymelinked glycosorbent assay, which was developed by the conjugation of horseradish peroxidase with fetuin, a sialic acid-containing glycoprotein which was specific to H. pylori adhesion. FlA contained the highest carbohydrate content among polysaccharide fractions, and no protein was detectable when further purified by gel filtration FPLC. Sugar composition analysis using GC revealed the highest amount of galacturonic acid among sugars, which suggests that FlA contains essentially acidic polysaccharides. Our data suggest that acidic polysaccharides may play an important role in the inhibition of H. pylori adhesion to host cells.

• Microbiology and Biotechnology Letters
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• v.31 no.2
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• pp.135-139
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• 2003

During the screening for inhibitors of melanin biosynthesis from plant extract, Angelica polymorpha MAXIM which showed a high level of inhibition was selected. The inhibiting substances were purified form methanol extract of Angelica polymorpha MAXIM followed by silica gel column chromatography and HPLC. The inhibitors were identified as heraclenin, isosaxalin and heraclenol 3'-Me ether, by spectrescopic methods of ESI-MS, H-NMR, C-NMR, DEPT, HMQC and HMBC. These compounds did not have mushroom tyrosinase inhibitory activity, but showed a highly potent melanin biosynthesis inhibition zone in the plate culture of Streptomyces bikiniensis, a bacterium used as an indicator organism in this work. These compounds did not show any growth inhibition against S. bikiniensis at the same concentration of melanin biosynthesis test.

• Korean Journal of Oriental Medicine
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• v.10 no.1
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• pp.119-126
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• 2004

For the purpose of developing new anti-HIV agents from natural sources, the extracts of Solanum nigrum L. were tested for their inhibitory effects on HIV-1 replication and its essential enzymes as the reverse transcriptase (RT), protease and ${\alpha}$-glucosidase. In the assay of HIV-1-infected human T-cell line, water extracts inhibited the HIV- 1 -induced cytopathic effects with IC (inhibitory concentration) of 100 ug/ml. Moreover water extracts (100ug/ml) of aerial parts showed strong activity of 32.6% on anti-HIV-1 PR using the activity of the enzyme to cleave an oligopeptide. In the HIV-1 reverse transcriptase inhibition assay, aqueous extract a inhibited 17.4%, but no glucosidase inhibitory activities. We found out this result, for these samples it is possible that the inhibition of the viral replication in vitro is due to the inhibition at least one of PR and RT. It would be of great interest to identify the compounds which are responsible for this inhibition, since all therapeutically useful agent up to date are PR, RT and ${\alpha}$-glucosidase inhibitors.

• Herbal Formula Science
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• v.9 no.1
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• pp.335-354
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• 2001

This study was designed to investigate biological activity of antler extract added medical plants. The scavenging activity of DPPH radical was low scavenging activity at 0.01% concentration. But in the 0.05% and higher concentration, electron donating ability(EDA) is above 50% except Kongindangagam(48.5%) and significantly good above 70% in the 4 extracts. Superoxide dismutase(SOD)-like activity was 44.3% and 45.1% extracts of Ohjayenjongwhangami and M(market sample), Inhibition of xanthine oxidase were above 50% at 0.5% concentration except Boshingiwhangwhangami and from 62.4% to 84.9% in the 4 extracts. Inhibition rate of boshingiwhangwhangami was hasty increased from 33.5% to 77.5% at 1.0% concentration and others the higher concentration, the more increasing inhibition. Angiotension I-converting enzyme(ACE) inhibitory activities were high activity all of extracts. In the 0.5% concentration, ACE inhibition was above 80%. Especially 0.01% concentration of M was presented 81.8%. The study which conducted to investigate the effect of feeding antler extract group for 50 days on sperm concentration, Ca contents of serum, kidney and femur in rats was higher than that saline group.

• The Korean Journal of Physiology
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• v.11 no.1
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• pp.1-9
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• 1977

Action of anthraquinone on the sodium plus potassium activated ATPase activity in the rabbit red cell membrane has been investigated and the experiments were also designed to determine the mechanism of action of anthraquinone on the ATPase activity. The following results were obtained 1. The activity of the NaK ATPase from red cell membrane is inhibited by anthraquinone and the concentration of anthraquinone for maximal inhibition is about 5mM. 2. The ratio of inhibition of NaK ATPase by anthraquinone, with a giving concentration of sodium in the medium, is increased by raising the potassium concentration. 3. The ratio of inhibition of NaK ATPase by anthraquinone, with a given concentration of potassium in the medium, is increased by raising the sodium concentration. 4. The action of anthraquinone on the NaK ATPase activity is inhibited by calcium ions and the ratio of inhibition is increased by small amounts of calcium but almost constant by larger amounts. 5. The inhibitory action of anthraquinone on the NaK ATPase activity was not related to the amino group of lysine, the hydroxyl group of threonine or the imidazole group of histidine. 6. The inhibitory action of anthraquinone on the ATPase activity is due to sulfhydryl group or the carboxyl group of the enzyme of NaK ATPase.

• BMB Reports
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• v.28 no.6
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• pp.471-476
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• 1995

Acetolactate synthase (ALS) catalyzes the first common step in the biosynthesis of valine, leucine, and isoleucine. ALS is the target enzyme for several classes of structually diverse herbicides. We have synthesized 4,6-dimethoxypyrimidine derivatives as ALS inhibitors, and their inhibitory activities on barley ALS were determined. $IC_{50}$ values for the derivatives are 0.2~200 ${\mu}m$. K11570, the most potent ALS inhibitor with $IC_{50}$ of 0.2 ${\mu}m$, showed mixed-type inhibition with respect to substrate pyruvate, and the progress curves for ALS inhibition by K11570 indicated that the amount of inhibition increased with time. Inhibition-competition experiments were carried out and indicated that three different classes of inhibitors, K11570, a sulfonylurea Ally, and leucine, bind to ALS in a mutually exclusive manner. Chemical modification of tryptophanyl and tyrosyl residues of ALS decreased the sensitivity of ALS to K11570, while cysteine modification did not affect the sensitivity. These results suggest that tryptophanyl and tyrosynyl residues are probably located at or near the inhibitor binding site.