• Korean Journal of Medicinal Crop Science
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• v.24 no.1
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• pp.7-13
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• 2016

Background : Ginger has been extensively used in foods and traditional medicines in Asian countries. Despite its frequent consumption in daily life, the mechanism of potential interactions between ginger components-drug has not been examined. To elucidate the mechanism of governing the effects of 6-shogaol, a primary constituent of dried ginger, on human cytochrome P450 (CYP) isoenzymes an incubation studies were carried out using pooled human liver microsome (HLM). Methods and Results : CYP isoenzyme specific substrate was incubated with multiple concentrations of inhibitor, HLM and cofactors. 6-shogaol showed a potent inhibitory effect on CYP2C9, CYP1A2 and CYP2C19 with half maximal inhibitory concentration ($IC_{50}$) values of 29.20, 20.68 and $18.78{\mu}M$ respectively. To estimate the value of the inhibition constant ($K_i$) and the mode of inhibition, an incubation study with varying concentrations of each CYP isoenzyme-specific probe was performed. 6-shogaol inhibited CYP2C9 and CYP2C19 noncompetitively ($K_i=29.02$ and $19.26{\mu}M$ respectively), in contrast, the inhibition of CYP1A2 was best explained by competitive inhibition ($K_i=6.33{\mu}M$). Conclusions : These findings suggest that 6-shogaol may possess inhibitory effects on metabolic activities mediated by CYP1A2, CYP2C9 and CYP2C19 in humans.

• Journal of Life Science
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• v.14 no.4
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• pp.627-635
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• 2004

In order to distinguish the genetic polymorphism among the olive flounder (Paralichthys olivaceus) obtained from East sea of Jumunjin, aquaculture of Tongyoung and Geoje, and East sea of North Korea, the ND-4 and cytochrome b genes of olive flounder were divided into 5 regions. Each region was analyzed by degenerating gel electrophoresis scanning (DGES), and by subsequent DNA sequencing. The DGES disclosed characteristic DNA polymorphisms in ND-4-2 and ND-4-3 regions of olive flounder, which were also confirmed by the DNA sequencing. The olive flounders obtained from the different marine areas showed DNA mutations in ND-4-2 region (G390A, C402T, and A411G； GenBank： AB028664), and also showed frequent DNA mutations in ND-4-3 region (C515G, C537T, C538T, A567G, G714A, C736T, G756A, A759T, T817C, and T829G), white the cytochrome b gene showed no DNA mutation both in the DGES and DNA sequencing. These data suggest that the ND-4-2 and ND-4-3 regions are candidate loci to distinguish the origin of olive flounder, and that the DGES used in this study provided fast and reliable informations for the genetic polymorphism.

• Journal of Life Science
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• v.13 no.1
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• pp.118-127
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• 2003

$\rho$-Fluorophenylalanine (FPA), a phenylalanine analog, is able to induce apoptotic cell death of human acute leukemia Jurkat T cells. To better understand the mechanism by which FPA induces apoptotic cell death, the effect of ectopic expression of antiapoptotic proteins, Bcl-2 and Bcl-xL, on FPA-induced apoptosis was investigated by employing lurkat T cells transfected with Bcl-2 gene (JT/Bcl-2) or Bcl-xL gene (1/Bcl-xL) and Jurkat T cells transfected with vector (JT/Neo or J/Neo). When Jurkat T cells, JT/Neo or J/Neo, were exposed to FPA at concentrations ranging from 0.63 to 5.0 mM, the cell viability determined by MTT assay declined in a dose-dependent manner. In addition, apoptotic DNA fragmentation along with several apoptotic events such as caspase-8 activation, Bid cleavage, mitochondrial cytochrome c release, caspase-9 activation, caspase-3 activation, and degradation of PARP was induced. However, the FPA-induced cytotoxic effect, activation of caspase-8, and cleavage of Bid were significantly abrogated by ectopic expression of Bcl-2 or Bcl-xL. At the same time, there was marked reduction in the level of cytochrome c release from mitorhondria, caspase-9 activation, caspase-3 activation, and degradation of PARP. These results indicate that caspase-8 activation, Bid cleavage, and mitochondrial cytochrome c release with subsequent activation of the caspase cascade are negatively regulated by Bcl-2 or Bcl-xL, and are thus required for FPA-induced apoptosis in Jurkat T cells

• The Korean Journal of Pharmacology
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• v.23 no.2
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• pp.113-121
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• 1987

Local anesthetics were investigated for their effects on mitochondrial electron transport system, production of superoxide radical from submitochondrial particles and malondialdehyde production through lipid per oxidation. Local anesthetics had various effects on activities of enzymes in electron transport chain. The activities of NADH dehydrogenase, NADH oxidase and NADH-ubiquinone oxidoreductase were effectively inhibited by lidocaine, procaine and dibucaine but slightly influenced by cocaine. The activities of succinate dehydrogenase, succinate-cytochrome c oxidoreductase and succinate-ubiquinone oxidoreductase were inhibited by lidocaine and dibucaine, but the succinate oxidase activity was stimulated by local anesthetics. Both dihydroubiquinone-cytochrome c oxidoreductase and cytochrome c oxidase activities were inhibited by local anesthetics. In these reactions, the response of Complex I segment to local anesthetics was greater than other Complex segments. Local anesthetics inhibited both the superoxide production from submitochondrial particles supplemented with succinate or NADH and the enhanced production of superoxide radicals by antimycin. The malondialdehyde production by oxygen free radicals was inhibited by local anesthetics. These results suggest that the inhibition of superoxide and malondialdehyde production caused by local anesthetics may be brought by suppression of the electron transport in mitochondria at sites in or near complex I segment.

• YAKHAK HOEJI
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• v.23 no.2
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• pp.111-118
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• 1979

It was previously reported that cytochrome P$_{450}$ content in liver was increased when Capsicum acetone extract was given chronically to rats. The present study is aimed to investigate the effect of capsaicin, a principal component of red pepper, on the drug metabolizing enzymes in rat liver. Capsaicin (5mg/kg) was given intraperitoneally once a day for seven days and zoxazolamine paralysis time and hexobarbital sleeping time were determined 24 hrs after the last dose of capsaicin. Plasma hexobarbital concentration was also determined five and 15 min after hexobarbital administration to rats. Zoxazolamine paralysis time and hexobarbital sleeping time were shortened by 31.6% and 37.1%, respectively, compared with control group. Plasma hexobarbital concentration was lowered by 26.2% after five min and by 35.2% after 15 min, respectively, compared with control group. However, administration of single dose of capsaicin did not affect the zoxazolamine paralysis time and hexobarbital sleeping time. Microsomal cytochrome P$_{450}$ content and NADPH-cytochrome C reductase activity were increased by 14.6% and 11.6%, respectively in the rats pretreated with capsaicin for seven days, while cytochrome b$_{5}$ content was not changed. These results suggest that treatment with capsaicin for seven days may induce the drug metabolizing enzyme in rat liver.

• BMB Reports
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• v.38 no.3
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• pp.366-369
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• 2005

NADPH-cytochrome P450 reductase (CPR) transfers electrons from NADPH to cytochrome P450 and also catalyzes the one-electron reduction of many drugs and foreign compounds. Various spectrophotometric assays have been performed to examine electron-accepting properties of CPR and its ability to reduce cytochrome $b_5$, cytochrome c, and ferricyanide. In this report, reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) by CPR has been assessed as a method for monitoring CPR activity. The principle advantage of this substance is that the reduction of MTT can be assayed directly in the reaction medium by a continuous spectrophotometric method. The electrons released from NADPH by CPR were transferred to MTT. MTT reduction activity was then assessed spectrophotometrically by measuring the increase of $A_{610}$. MTT reduction followed classical Michaelis-Menten kinetics ($K_m\;=\;20\;{\mu}M$, $k_{cat}\;=\;1,910\;min^{-1}$). This method offers the advantages of a commercially available substrate and short analysis time by a simple measurement of enzymatic activity of CPR.

• Journal of Microbiology and Biotechnology
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• v.16 no.6
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• pp.974-978
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• 2006

The cytochrome P450 monooxygenase from the pikromycin biosynthetic gene cluster in Streptomyces venezuelae, known as PikC, was observed to hydroxylate the unnatural substrate indole to indigo. Furthermore, the site-directed mutagenesis of PikC monooxygenase led to the mutant enzyme F171Q, in which Phe171 was altered to Gln, with enhanced activity for the hydroxylation of indole. From enzyme kinetic studies, F171Q showed an approximately five-fold higher catalytic efficiency compared with the wild-type PikC. Therefore, these results demonstrate the promising application of P450s originating from Streptomyces, normally involved in polyketide biosynthesis, to generate a diverse array of other industrially useful compounds.

• Applied Biological Chemistry
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• v.38 no.5
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• pp.463-467
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• 1995

In vitro metabolism study of ${\alpha}$-endosulfan by liver and kidney microsomal cytochrome P-450 monooxygenase system of the mouse(Balb/C) was performed. ${\alpha}$-Endosulfan was metabolized to endosulfan lactone(EL), endosulfan hydroxyether(EHE), endosulfan alcohol(EA), endosulfan sulfate(ES), endosulfan ether(EE) and ${\beta}$-endosulfan(${\beta}$-E). The main metabolites of ${\alpha}$-endosulfan were EL(13.2%) and EA(11.5%) in liver microsome and EA(17.4%) md EHE(19.3%) in kidney microsome. The $^{14}C$-activity of organic extractable fraction and water soluble fraction were 63.4% and 31.7% in liver micosome incubates respectively. The water soluble metabolites were EA(83.9%), EHE(4.5%) and ES(2.3). Piperonyl butoxide treatment inhibited the formation of EE by 86%, EA by 92% and EHE, EL and ES were barely formed.

• Toxicological Research
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• v.18 no.3
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• pp.249-257
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• 2002

Cytochrome P450 3As such as 3A4 and 3A5 metabolize a wide range of pharmaceutical compounds. The vectors for the expression of fusion protein containing an N-terminal human P450 3A4 or P450 3A5 sequences and a C-terminal rat NADPH-cytochrome P450 reductase moiety were constructed. These plasmids were used to express the fusion protein in Escherichia coli DH5$\alpha$ cells. High levels of expression were achieved (100~200 nmol/liter) and the expressed fusion protein in E. coli membranes were catalytically active for nifedipine oxidation, a typical enzymatic activity of P450 3A4. The NADPH-P450 reductase activities of these fusion protein were also determined by measuring reduction of cytochrome c. To fine a specific Inhibitor of P450 3A4 from naturally occurring chemicals, a series of isothiocyanate compounds were evaluated for the inhibitory activity of P450 using the fusion proteins in E. coli membranes. Of the five isothiocyanates (phenethyl isothiocyanate, phenyl isothiocyanate, benzol isothiocyanate, benzoyl isothiocyanate and cyclohexyl isothiocyanate) tested, benzoyl isothiocyanate showed a strong inhibition of P450 3A4 with an $IC_{50}$value of 2.8 $\mu\textrm{M}$. Our results indicate that the self-sufficient fusion protein will be very useful tool to study the drug metabolism and benzyl isothiocyanate may be valuable for characterizing the enzymatic properties of P450 3A4.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2001.12a
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• pp.119-120
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• 2001