• Archives of Pharmacal Research
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• v.22 no.5
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• pp.464-473
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• 1999

Regulation of phosphcholine-hydrolyzing phosphatase (phosphocholine-phosphatase) activity, purified from bovine brain, was examined under physiological conditions. Various endogenous phosphomonoesters, which were utilized as substrate, inhibited the phosphocoline-phosphatase activity competitively (Ki 5.5-$82.0 {\mu}M$); among phosphomonoesters tested, there was a similar order of capability between the binding affinity of substrate and the inhibitory potency. In addition, phosphate ions also inhibited the phosphatase activity competitively with a Ki value of approximately $16{\mu}M$. Although leucine or theophylline inhibited the phosphatase activity at pH 9.0, their inhibitory action decreased greatly at pH 7.4. The pH-Km and pH-Vm profiles indicate that ionizable amino acids are involved in substrate binding as well as catalysis, alluding that the phosphatase activity may be highly dependent on the intracellular pH. Amino acid modification study supports the existence of tyrosine, arginine or lysine residue in the active site, and the participation of tyrosine residue in the catalytic action may e suggested positively for the susceptibility to the action of tetranitromethane or HOl-generator. Separately, the oxidative inactivation of phosphocholine-phosphatase activity was investigated. Of oxidants tested, HOONO, HOCl, HOl and $ascorbate/Cu^{2+}$ system were effective to inactivate the phosphatase activity. Noteworthy, a remarkable inativation was accomplished by $30{\mu}M$ HOCl in combination with 1 mM Kl. Inaddition, $Cu^{2+}(3{\mu}M) $in combination with ascorbate at concentrations as low as 0.1-0.3 mM reduced the phosphatase activity to a great extent. From these results, it is proposed that the phosphocholine-phosphatase activity may be regulated endogenously and susceptible to the various oxidant system in vivo.

• Land and Housing Review
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• v.4 no.3
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• pp.235-241
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• 2013

There have been a lot of previous studies that brand image has a positive impact on purchase as well as the value enhancement of the product with the spread of brand importance and the introduction of brand in the apartment. This study verified that brand image can be factorized and separated into two factors - basic characteristics and additional characteristics. The basic characteristics means essential parts that generally should be provided for housing and the additional characteristics are competitively developed concepts introduced by construction companies for sales promotion. The results of the empirical analysis that verified the effects of the two factors on purchase intention are as follows. The basic characteristics have the positive impact on purchase intention while the additional characteristics are otherwise. This result suggests that it is more important to be faithful to the basics than to be competitively differentiated by the additional characteristics in the apartment market.

• Archives of Pharmacal Research
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• v.19 no.4
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• pp.258-260
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• 1996

Palmatine, an protoberberine isoquinoline alkaloid, has been found to inhibit dopamine biosynthesis by reducing tyrosine hydroxylase (TH) activity in PC12 cells (Lee and Kim, 1996). We have therefore investigated the effects of palmatine on bovine adrenal TH. Palmatine showed a mild inhibition on bovine adrenal TH (36.4% inhibition at concentration of $200\muM$). Bovine adrenal TH was inhibited competitively by palmatine with a substrate L-tyrosine. The Ki value was found to be 0.67 mM. This result suggests that the inhibition of TH activity by palmatine may be partially involved in the reduction of dopamine biosynthesis in PC12 cells.

• Journal of Microbiology and Biotechnology
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• v.6 no.2
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• pp.92-97
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• 1996

Portage kinetic constants of peptide transport can be measured by competitive spectrophotometry. The kinetic constants of L-Glu-L-Glu transport in Escherichia coli were ascertained using L-Phe-L-3-thia-Phe (PSP) as a detector. Since the production of thiophenol upon intracellular hydrolysis of PSP was competitively inhibited by L-Glu-L-Glu, it was able to compute the kinetic constants of L-Glu-L-Glu using this method. The resulted data were in agreement with the values obtained by the method of Michaelis-Menten kinetics. The potential of this method was examined against dipeptide transport systems in various microorganisms. These results strongly suggest that the overall properties of individual systems for dipeptide transports can be easily characterized by competitive spectrophotometry.

• Archives of Pharmacal Research
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• v.11 no.3
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• pp.230-239
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• 1988

Thirty kinds of medicinal plants were screened to examine inhibitory activities on rat brain monoamine oxidase A, using serotonin as a substrate. As active principles, various kinds of stilbenes were isolated from Veratri Rhizoma, Reynoutriae Radix and Rhei undulati Rhizoma, and several kinds of flavonoids from Sophorae Flos, Chrisanthemi Flos and Glycine max. Among the compounds isolated, resveratrol(I) strongly inhibited MAO-A competitively, and its $IC_{50}$ and Ki values were 2 ${\mu}M$ and 2.5 ${\mu}M$, respectively. Inhibitory potencies towards MAO-A of some stilbenes and flavonoids were also compared.

• Journal of the Korean Professional Engineers Association
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• v.37 no.5
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• pp.42-46
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• 2004

Automobile industry with history of more than 100 years is totally influencing all the economic environments and has very important wellbeing role in the World in every country of the world. Korean Automotive industry in production has only about 40 years but ranked remarkably 6th biggist in the world in the year of 2003. Nowadays The auto, industry has changed into buyer's market in competitively global battle fields and also is changing industry paradigm in product, sales, production, colarboration & emerging, etc. BRICs(Especially China)are rapidly emerging as main producers and customers in new big markets. Korea Auto. Industry faces crictical problems such as higher salary, furious labor union's striking lack of raw material, evasion of 3D works with studying engineering by students which are the key pending agenda that should be overcome for prosperous growth and development of achieving US20,000 GNP.

• Journal of Electrical Engineering and Technology
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• v.11 no.6
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• pp.1700-1706
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• 2016

In this paper, a dual-stator, spoke-type linear vernier machine (DSSLVM) for wave energy extraction application was proposed. This machine is capable of producing a competitively high thrust force and force density at a low operation speed in direct drive systems. The operation principal and working of the proposed DSSLVM were studied. The stator core height is adjusted to improve the overall force density of the proposed machine while reducing the force ripple. To evaluate the advantages of the proposed DSSLVM, the main performance was compared with that of a recently developed linear primary permanent magnet vernier machine (LPPMVM). The proposed machine exhibited greater thrust force and force density, an improved power factor and lower force ripple with the same permanent magnet (PM) volume compared to the LPPMVM.

• Journal of the Korea Computer Graphics Society
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• v.2 no.1
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• pp.86-92
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• 1996

Multimedia services through a network are getting more required according to the realization of B-ISDN construction globally. Business using the Internet will become popular, and so multimedia information systems including telemarketing systems will be developed competitively. VR (Virtual Reality) will help such systems make more realistic and valuable. ln this paper, we present an interactive VR authoring tool and a client/server based multimedia information service system. The VR authoring tool serves an interface with the system when developing its applications.

• Natural Product Sciences
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• v.6 no.2
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• pp.70-72
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• 2000

The effects of coptisine on monoamine oxidase (EC 1.4.3.4; MAO) activity in mouse brain were investigated. Coptisine showed an inhibitory effect on MAO activity with a concentration-dependent manner. Coptisine exhibited 51.0% inhibition of MAO activity at $9\;{\mu}M$. The $IC_{50}$ value of coptisine was $8.7\;{\mu}M$. Coptisine inhibited MAO activity competitively with kynuramine as a substrate. The $K_i$ value of coptisine was $4.1\;{\mu}M$. These results indicate that coptisine functions to regulate the catecholamine content at biologically active sites.

• BMB Reports
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• v.28 no.2
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• pp.94-99
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• 1995

The properties of binding sites in the active site of $Zn^{2+}$-glycerophosphocholine cholinephosphodiesterase were examined using substrates and inhibitors of the enzyme. Phosphodiesterase hydrolyzed p-nitrophenylphosphocholine, p-aminophenylphosphocholine, and glycerophosphocholine, but did not hydrolyze either acylated glycerophosphocholine or bis (p-nitrophenyl)phosphate, suggesting a size limitation for interaction with a glyceryl moiety-binding subsite. The hydrolysis of p-nitrophenylphosphocholine was competitively inhibited by glycerophosphocholine and p-aminophenylphosphocholine, while glycerophosphoethanolamine was a weak inhibitor. The enzyme was also inhibited by choline, but not by ethanolamine. Thiocholine, a much more potent inhibitor than choline, was more inhibitory than cysteamine, suggesting a strict specificity of an anionic subsite adjacent to a $Zn^{2+}$ subsite. Of all oxyanions tested, the tellurite ion was found to strongly inhibit the enzyme by binding to a $Zn^{2+}$ subsite. The inhibitory role of tellurite was synergistically enhanced by tetraalkylammonium salts, but not by glycerol. Deactivation of the enzyme by diethylpyrocarbonate was partially protected by choline, but not by glycerophosphate. It is suggested that the active site of phosphodiesterase contains three binding subsites.