• Proceedings of the Korean Society of Life Science Conference
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• 2003.10a
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• pp.55-55
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• 2003

• Proceedings of the Korean Society of Life Science Conference
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• 2002.03a
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• pp.117-117
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• 2002

• The Korean Journal of Pharmacology
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• v.26 no.2
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• pp.185-192
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• 1990

The present work was undertaken to investigate the protective effect of diallyl disulfide on the bromobenzene toxicity in mice. It was observed that the aniline hydroxylase and epoxide hydrolase activities were not changed by the treatment of diallyl disulfide for 5 days. But glutathione S-transferase activity was significantly increased. A striking enhancement of serum alanine aminotransferase activity and hepatic lipid peroxide content after bromobenzene administration was markedly decreased by diallyl disulfide pretreatment. These results indicate that the inducing effects of diallyl disulfide on the bromobenzene intermediate detoxifying enzyme such as glutathione S-transferase are believed to be a possible protective mechanism for the bromobenzene toxicity in mice.

• Journal of Microbiology and Biotechnology
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• v.18 no.8
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• pp.1445-1452
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• 2008

An open reading frame (ORF) encoding a putative epoxide hydrolase (EHase) was identified by analyzing the genome sequence of Sphingophyxis alaskensis. The EHase gene (seh) was cloned and expressed in E. coli. To facilitate purification, the gene was fused in-frame to 6$\times$ histidine at the C-terminus. The recombinant EHase (rSEH) was highly soluble and could be purified to apparent homogeneity by one step of metal affinity chromatography. The purified SEH displayed hydrolyzing activities toward various epoxides such as styrene oxide, glycidyl phenyl ether, epoxyhexane, epoxybutane, epichlorohydrin, and epifluorohydrin. The optimum activity toward styrene oxide was observed at pH 6.5 and $35^{\circ}C$. The purified SEH showed a cold-adapted property, displaying more than 40% of activity at low temperature of $10^{\circ}C$ compared with the optimum activity. Despite the catalytic efficiency, the purified SEH did not hydrolyze various epoxides enantioselectively. $K_m$ and $k_{cat}$ of SEH toward (R)-styrene oxide were calculated as 4$\pm$0.3 mM and 7.42$s^{-1}$ respectively, whereas $K_m$ and $k_{cat}$ of SEH toward (S)-styrene oxide were 5.25$\pm$0.3 mM and 10.08$s^{-1}$ respectively.

• Korean Journal of Pharmacognosy
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• v.31 no.2
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• pp.228-234
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• 2000

Effects of Houttuynia cordata on the level of lipid peroxide and the enzyme activities of the liver were investigated in bromobenzene-induced rats. Lipid peroxide content in liver was increased by bromobenzene. It was decreased when the methanol extract from the aerial parts of H. cordata was treated to the rat. The methanol extract reduced the activities of aminopyrine N-demethylase and aniline hydroxylase that increased by bromobenzene, however did not affect glutathione S-transferase activity. The methanol extract recovered the activity of epoxide hydrolase activity that decreased significantly by bromobenzene. We suggest that under our experimental conditions the extract might play an important play in the prevention of hepatotoxicity by reduction of aminopyrine N-demethylase and aniline hydroxylase activities as well as enhancement of epoxide hydrolase activity. Six phenolic compounds have been isolated from H. cordata and identified by means of spectral analysis as protocatechuic acid, quercetin, apigenin, afzelin, hyperoside and quercitrin.

• Natural Product Sciences
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• v.21 no.3
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• pp.176-184
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• 2015

In our search for natural soluble epoxide hydrolase (sEH) inhibitors from plants, an extract of the dried whole plants of Euphorbia supina Rafin was found to significantly inhibit sEH activity in vitro. Phytochemical investigation of E. supina resulted in isolation of 17 compounds (1 - 17), including triterpenes (1 - 4), phenolic compounds (5 - 8), and flavonoid derivatives (9 - 17). The structures of the isolated compounds were established mainly by extensive analysis of the 1D and 2D NMR, and MS data. All of the isolated compounds were evaluated for their sEH inhibitory activity. Among the isolated phenolic compounds, 8 was identified as a significant inhibitor of sEH, with an IC₅₀ value of 15.4 ± 1.3 μM. Additionally, a kinetic analysis of isolated compounds (2, 5, 8 - 11, 13, and 17) indicated that the inhibitory effects of flavonoid derivatives 10 and 11 were of mixed-type, with inhibitory constants (K_i) ranging from 3.6 ± 0.8 to 21.8 ± 1.0 μM, whereas compounds 2, 5, 8, 9, 13, and 17 were non-competitive inhibitors with inhibition K_i values ranging from 3.3 ± 0.2 to 39.5 ± 0.0 μM.

• Journal of Life Science
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• v.13 no.6
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• pp.794-798
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• 2003

Batch production of (S)-phenyl oxirane was investigated using epoxide hydrolase activity of Rhodosporidium toruloides SJ-4. Effect of reaction condition of asymmetric biohydrolysis of racemic phenyl oxirane was analyzed and optimized by response surface methodology. The optimal conditions of pH, temperature and DMSO cosolvent ratio were 7.4, $34^P\circ}C$, and 2.3%(v/v), respectively. The final yield was enhanced up to 67%, and reaction times required to reach 99% ee (enatiomeric excess) decreased down to 50% by response surface methodology Enantiopure (S)-phenyl oxirane with 100% enantiopurity and 24% yield (theoretical yield = 50%) was obtained from racemic substrate.

• Microbiology and Biotechnology Letters
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• v.35 no.4
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• pp.285-291
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• 2007

Enantioconvergent hydrolysis process for the preparation of chiral diol from racemic epoxides by using the recombinant Caulobacter crescentus epoxide hydrolase (CcEH) in Escherichia coli BL21 (DE3) was optimized. For the optimization, the effects of detergent, temperature and product inhibition on the enantiopurity and the yield of diol were investigated. (R)-phenyl-1,2-ethanediol with 92% enantiomeric excess and 56% yield from 20 mM racemic styrene oxide was obtained by using the recombinant CcEH at the optimal condition of $10^{\circ}C$ and the addition of 2% (w/v) Tween 80. At 50 mM racemic styrene oxide was used as a substrate, (R)-phenyl-1,2-ethanediol was obtained with 87% enantiomeric excess and 77% yield. Racemic phenyl-1,2-ethanediol, (R)-phenyl-1,2-ethanediol and (S)-phenyl-1,2-ethanediol dramatically inhibited the hydrolytic activity of the recombinant CcEH. These results suggested that another EH with the regioselectivity on ${\beta}$-position of (R)-enantiomer and without feedback inhibition by products would be needed as the partner EH of C. crescentus EH.

• Journal of Life Science
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• v.18 no.1
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• pp.136-142
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• 2008

A recombinant Pichia pastoris carrying double expression cassette of Rhodotorula glutinis epoxide hydrolase(RgEH) gene was developed and used for preparing enantiopure (S)-styrene oxide from racemic mixture of styrene oxide. BglII restriction site of original RgEH gene (pPICZ B/RgEH #2) of previous report was mutated using PCR technique for the construction of double expression cassette containing promoter ($P_{AOX1}$), EH gene and transcription terminator ($TT_{AOX1}$) in pPICZ C vector. Double expression cassette with RgEH was inserted into the chromosomal DNA of P. pastoris. $V_{max}$ ($2.2{\mu}mol\;min^{-1}mg\;dcw^{-1}$) on (R)-styrene oxide of P. pastoris with double expression cassette was about 6-fold higher than that ($0.4{\mu}mol\;min^{-1}mg\;dcw^{-1}$) of P. pastoris with single expression cassette. For the determination of the optimal condition, the effects of detergent and temperature on the enantioselective hydrolytic activity and yield of the enantiomer were investigated. When the reaction was performed at $10^{\circ}C$ for 10 min in the presence of 0.5% Tween 20, enantiopure (S)-styrene oxide with 99.9% ee was obtained as the yield 43.4 % from 20 mM racemic sustrate.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.6
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• pp.702-708
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• 1993

The study was attempted to elucidate the mechanism of GE-132(100mg/kg, p.o. for 6 weeks) on the metabolism of bromobenzene (460mg/kg, i.p. bid, for 2 days), which has potent carcinogenicity, mutagenicity and hepatotoxicity. It showed that activities of cytochrome p-450, aminopyrine demethylase and aniline hydroxylase, which have epoxide generating property, were not changed by GE-132 treatment. On the other hand, epoxide hydrolase was not changed but that glutathione S-transferase was significantly increased by GE-132 treatment. And also ${\gamma}-glutamylcysteine$ synthetase was not changed following the GE-132 treatment, but the activity of glutathione reductase was significantly increased. The level of hepatic glutathione which was decreased by bromobenzene recovered markedly by GE-132 pretreatment. It is concluded that the mechanism for the observed effect of GE-132 on bromobenzene metabolism is due to the induction of glutathione S-transferase.