• Toxicological Research
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• 제26권1호
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• pp.47-52
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• 2010

The Malassezia fungi are responsible for various human skin disorders including dandruff and seborrheic dermatitis. Of the Malassezia fungi, Malassezia globosa (M. globosa) is one of the most common in human scalp. The completed genome sequence of M. globosa contains four putative cytochrome P450 genes. To determine the roles of Malassezia P450 enzymes in the biosynthesis of ergosterol, we isolated MGL3996 gene from M. globosa chromosomal DNA by PCR. The MGL3996 gene encodes an enzyme of 616 amino acids, which shows strong similarity with known CYP52s of other species. MGL3996 gene was cloned and expressed in Pichia pastoris (P. pastoris) heterologous yeast expression system. Using the yeast microsomes expressing MGL3996 protein, a typical P450 CO-difference spectrum was shown with absorption maximum at 448 nm. SDS-PAGE analysis revealed a protein band of apparent molecular weight 69 kDa and Western blot with anti-histidine tag antibody showed that MGL3996 was successfully expressed in P. pastoris. Cloning and expression of a new P450 gene is an important step to study the P450 monooxygenase system of M. globosa and to understand the role of P450 enzymes in pathophysiology of dandruff.

• Clinical and Experimental Reproductive Medicine
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• 제28권2호
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• pp.131-140
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• 2001

Objective: To know the effects of xenoestrogen on spermatogenesis, we investigated the expression of cytochrome P450s enzymes (CYPscc, $CYP_{17{\alpha}}$, CYP19) and $3{\beta}$-HSD genes involved in steroidogenesis. Methods: Mouse testicular cells were prepared from 15-day-old ICR mice which had only pre-meiotic germ cells by enzyme digestion using collagenase and trypsin. Testicular cells were cultured in DMEM supplemented with FSH (0.1 IU/ml) and 10% FBS or medium with estrogen ($E_2$), bisphenol-A (BPA), octylphenol (OP; $10^{-9},\;10^{-7},\;10^{-6},\;10^{-5},\;10^{-4}M$, respectively) and aroclor 1254 (A1254) known as PCBs for 48 hours. The gene expression of cytochrome P450 enzymes were examined by semi-quantitive RT-PCR. The production of estrogen and testosterone was examined by RIA. Results: As results, expression of CYPscc mRNA was not significantly decreased, but $3{\beta}$-HSD and $CYP_{17{\alpha}}$. mRNA were significantly dose-dependent decreased. And production of testosterone and estrogen were not different except BPA and OP group ($10^{-5}M$). Conclusion: BPA, OP and A1254 might inhibit steroidogenesis by decreasing CYPscc, $3{\beta}$-HSD and $CYP_{17{\alpha}}$. mRNA expression in the mouse testis. These results suggest that BPA, OP and PCBs like as an endocrine disruptors inhibit the productions of steroidogenic enzymes and decrease the production of T and E by negative feedback mechanism. Therefore, these might disrupt steroidogenesis in Leydig cells of testis and would disturb testicular function and subsequently impair spermatogenesis.

• Journal of Microbiology and Biotechnology
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• 제29권1호
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• pp.44-54
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• 2019

Geldanamycin and its derivatives, inhibitors of heat shock protein 90, are considered potent anticancer drugs, although their biosynthetic pathways have not yet been fully elucidated. The key step of conversion of 4,5-dihydrogeldanamycin to geldanamycin was expected to catalyze by a P450 monooxygenase, Gel16. The adequate bioconversions by cytochrome P450 mostly rely upon its interaction with redox partners. Several ferredoxin and ferredoxin reductases are available in the genome of certain organisms, but only a few suitable partners can operate in full efficiency. In this study, we have expressed cytochrome P450 gel16 in Escherichia coli and performed an in vitro assay using 4,5-dihydrogeldanamycin as a substrate. We demonstrated that the in silico method can be applicable for the efficient mining of convenient endogenous redox partners (9 ferredoxins and 6 ferredoxin reductases) against CYP Gel16 from Streptomyces hygroscopicus. The distances for ligand FDX4-FDR6 were found to be $9.384{\AA}$. Similarly, the binding energy between Gel16-FDX4 and FDX4-FDR6 were -611.88 kcal/mol and -834.48 kcal/mol, respectively, suggesting the lowest distance and binding energy rather than other redox partners. These findings suggest that the best redox partners of Gel16 could be NADPH ${\rightarrow}$ FDR6 ${\rightarrow}$ FDX4 ${\rightarrow}$ Gel16.

• Archives of Pharmacal Research
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• 제22권2호
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• pp.99-107
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• 1999

A series of organosulfur compounds were synthesized with the aim of developing chemopreventive compounds active against hepatotoxicity and chemical carcinogesis. 2-(Allylthio) prazine (2-AP) was effective in inhibiting cytochrome P450 2E1-mediated catalytic activities and protein expression, and in inducing microsomal epoxide hydrolase and major glutathione S-transferases. 2-AP reduced the hepatotoxicity caused by toxicant sand elevated cellular GSH content. Development of skin tumors, pulmonary adenoma and aberrant crypt foci in colon by various chemical carcinogens was inhibited by 2-AP pretreatment. Anticarcinogenic effects of 2-AP at the stage of initiation of tumors were also observed in the aflatoxin B1 ($AFB_1$)-induced three-step medium-term hepatocarcinogenesis model. Reduction of $AFB_1$-DNA adduct by 2-AP appeared to result from the decreased formation of $AFB_1$-8,9-epoxide via suppression of cytochrome P450, while induction of GST 2-AP increases the excretion of glutathione-conjugated $AFB_1$ . 2-AP was a radioprotective agent effective against the lethal dose of total body irradiation and reduced radiation-induced injury in association with the elevation of detoxifying gene expression. 2-AP produces reactive oxygen species in vivo, which is not mediated with the thiol-dependent production of oxidants and that NF-KB activation is not involved in the induction of the detoxifying enzymes. the mechanism of chemoprotection by 2-AP may involve inhibition of the P450-mediated metabolic activation of chemical carcinogens and enhancement of electrophilic detoxification through induction of phase II detoxification enzymes which would facilitate the clearance of activated metabolites through conjugation reaction.

• 환경생물
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• 제22권1호
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• pp.177-183
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• 2004

유기주석화합물인 tributyltin chloride (TBTC), tributyltin oxide (TBTO)와 triphenyltin chloride (TPTC)를 넙치 간장으로 만든 미크로좀에 in vitro적으로 노출시켜서 이들 화합물의 대사에 관여하는 mixed function oxidase (MFO) 중 cytochrome P450 (CYP) 농도와 7-ethoxyresorufin deethylase (EROD) 활성의 변화를 조사하였으며, 또한 in vivo 실험에서는 TPTC를 넙치에게 복강주사(7.5 mg $kg^{-1}$ BW)하여 간장의 MFO (CYP농도, NADPH cytochrome c 환원효소 활성, NADH chtochrome b5 환원 효소 활성, EROD 활성) 반응을 경시적으로 조사하였다. 그 결과, in vitro에서는 TBTC, TBTO 및 TPTC가 모두 CYP 농도와 EROD 활성을 저해하였으며, 저해력은 TPTC가 가장 컸고 이어서 TBTO, TBTC의 순이었다. 유기주석화합물의 노출농도와 노출시간과 비례하면서 저해정도가 커졌으며, 특히 EROD활성의 저해는 노출농도에 크게 의존적이었다. 그리고 in vivo실험에서도 유기주석 화합물은 CYP농도, NADPH cytochrome c 환원효소 활성, NADH cytochrome b5 환원효소 활성, EROD 활성을 억제하였다. EROD 활성은 오염물질에 의한 반응이 민감하고 재현성도 있어 바람직한 측정지표로 이용될 수가 있을 것이다.

• 대한약학회:학술대회논문집
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• 대한약학회 2000년도 NEW STRATEGY FOR DRUG DEVELOPMENT IN POST-GENOMIC ERA(대한약학회)
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• pp.168.1-168.1
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• 2000

• Genomics & Informatics
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• 제7권4호
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• pp.187-194
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• 2009

Cytochrome P450 2E1 (CYP2E1) is a member of the cytochrome P450 superfamily, and it is a key enzyme responsible for the metabolic activation of many smallmolecular-weight compounds such as alcohol, which is classified as a human carcinogen. In this study, we identified 19 single nucleotide polymorphisms (SNPs) in CYP2E1 in Korean population. In these SNPs, we examined possible genetic association of CYP2E1 polymorphisms with HBV clearance and the risk of hepatocellular carcinoma (HCC). Five common polymorphic sites were selected, CYP2E1 polymorphisms at rs381-3867, rs3813870, rs2070673, rs2515641 and rs2480257, considering their allele frequencies, haplotype-tagging status and LDs for genotyping in larger-scale subjects (n=1,092). Statistical analysis demonstrated that CYP2E1 polymorphisms and haplotypes show no significant association with HBV clearance, HCC occurrence and onset age of HCC (p>0.05). Previous studies, however, have shown contradictory findings on associations of CYP2E1 polymorphisms with CYP2E1 activities and HCC risk. Comparing the contrasting results of previous researches suggest that CYP2E1 polymorphism is associated with CYP2E1 activity induced by ethanol, but is not directly associated with HCC risk. CYP2E1 variation/haploype information identified in this study will provide valuable information for future studies on CYP2E1.

• 한국환경독성학회:학술대회논문집
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• 한국환경독성학회 2002년도 춘계학술대회(Genomics, Proteomics, and Risk Assesment):환경독성 및 위해성 평가 국제 심포지움
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• pp.75-75
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• 2002

• 한국연초학회지
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• 제20권2호
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• pp.178-182
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• 1998

Previously, we showed that acetone enhanced aryl hydrocarbon hydroxylase (AHH) activity in only 3-methylcholanthrene (MC)- or $\beta$-naphtoflavone (BNF)-inducible microsomes of rat liver. In the present study, the possible mechanism underlying acetone action on AHH was investigated in the liver microsomes from MC-pretreated rats. Other n-alkylketones except acetone did not increase AHH activity, which rather decreased significantly with the length of alkyl side chain. Acetone had no effect on the activity of NADPH-cytochrome P450 reductase or inhibited the formation of 3-OH benzo(a)pyrene (B(a)P) in nonenzymatic model ascorbic acid system. However, in cumene hydroperoxide (CuOOH)-supported B(a)P hydroxylation, acetone enhanced its velocity remarkably by 30% at the optimal concentration (30 $\mu$M CuOOH and 1.0% acetone). From these results, we conclude that acetone may facilitate the formation of an activated oxygen species or the insertion of oxygen into B(a)P molecule in CYP1A rich microsomes.

• 한국식품영양과학회지
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• 제30권5호
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• pp.928-932
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• 2001

노루궁뎅이 버섯의 간 손상 억제 작용을 확인하고자 B($\alpha$)P투여로 간 독성이 유발된 마우스에서 과산화지질의 생성, 항산화에 관련된 효소 및 물질의 변화를 살펴본 결과, B($\alpha$)P투여로 인해 혈청 ALT와 AST의 활성, 간조직 중의 과산화지질 함량, cytochrome P450 함량, SOD, catalase 그리고 GSH-Px의 활성이 유의적으로 증가하였고, GSH함량과 GST활성은 감소하였다. 반면 노루궁뎅이 버섯 메탄올 추출물의 전처리로 인해 ALT 와 AST의 활성, 과산화지질 함량, cyto-chrome P450 함량 그리고 항상화효소인 SOd, catalase 및 GSH-Px의 활성이 유의적으로 감소하였으며 GSH 함량과 GST 활성은 증가하였다. 그리고 마우스의 간 조직에서 cyto-chrome P450 1Al isozyme의 단백질 발현을 western blotting 으로 조사한 결과, B($\alpha$)P투여로 대조군에 비해 현저히 증가한 단백질 발현이 노루궁뎅이 버섯 메탄올 추출물을 투여함으로써 감소됨을 확인하였다. 이상의 결과로 노루궁뎅이 버섯 메탄올 추출물은 생체 내에서 자유기로 인해 야기되는 간장의 산화적 손상을 효과적으로 억제할 수 있을 것으로 사료된다.