• Toxicological Research
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• 제13권4호
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• pp.385-391
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• 1997

Inductive effects of cytochrome P450 2B1 by $\alpha$- and $\beta$-ionone were characterized in individual liver lobes of male Sprague Dawley rats. When rats were administered ionones orally at 100, 300, and 600 mg/kg for 24 hr, cytochrome P450 2B1 was induced dose-dependently in liver S-9 fractions as measured by P450 2B-specific monooxygenases and Western immunoblotting. The activity of P450 1A- and P450 2B-specific monooxygenases was differentially expressed in each lobe of normal liver. In addition, the monooxygenase activity was induced by $\alpha$- and $\beta$-ionone with different potency in each lobe of the liver. Our present results indicate that the different induction of P450s by $\alpha$- and $\beta$-ionone in each lobe may explain different susceptibilities of rat liver lobes to certain hepatotoxicants which require metabolic activation for their toxicity and that $\alpha$- and $\beta$-ionone may be useful model inducers of P450 2B1 in studying the toxic mechanism of certain toxicants which may require the metabolic activation by P450.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.312.3-313
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• 2002

Recently we have reported that various hydroxystilbenes show strong inhibition of human P450 1 activity. A series of synthetic trans-stilbene derivatives were prepared and their inhibitory potentials were evaluated with the bacterial membrane of recombinant human P450 1A1, 1A2 or 1B1 coexpressed with human NADPH-P450 reductase to find new candidates for cancer chemoprevention, Of the compounds tested. SY-021 (3.5-dimethoxyphenyl vinyl thiophene) exhibited a potent inhibition of human P450 181 with an IC$_{50}$ value of 2 nM. SY-021 also showed the inhibitrion of P450 1A1 with IC$_{50}$ value of 61 nM and P450 1A2 with IC$_{50}$ value of 11 nM. SY-021 showed 31-fold selectivity for P450 1B1 over P450 1A1 and 6-fold selectivity for P450 1B1 over 1A2. We have further investigated the inhibition kinetics of P450 1A1. 1A2 and 1B1 by SY-021. The modes of inhibition by SY-021were non-compeitive for all three P450 1 enzymes. Effect of preincubation with NADPH on inhibition of P450 1B1 by SY-021 was determined. These results suggest that SY-021 is one of the mostj potent inhibitor of human P450 1 enzymes and may be considered as a good candidate for a cancer chemopreventive agent in human

• Archives of Pharmacal Research
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• 제27권2호
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• pp.199-205
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• 2004

Cytochrome P450 (P450) 1 enzymes such as P450 1A1, 1A2, and 181 are known to be involved in the oxidative metabolism of various procarcinogens and are regarded as important target enzymes for cancer chemoprevention. Previously, several hydroxystilbene compounds were reported to inhibit P450 1 enzymes and were rated as candidate chemopreventive agents. In this study, we investigated the inhibitory effect of 2-[2-(3,5-dimethoxyphenyl)vinyl]-thiophene (DMPVT), produced from the chemical modification of oxyresveratrol, on the activities of P450 1 enzymes. The inhibitory potential by DMPVT on the P450 1 enzyme activity was evaluated with the Escherichia coli membranes of the recombinant human cytochrome P450 1A1, 1A2, or 1B1 coexpressed with human NADPH-P450 reductase. DMPVT significantly inhibited ethoxyresorufin O-deethylation (EROD) activities with $IC_{50}$ values of 61, 11, and 2 nM for 1A1, 1A2, and 1B1, respectively. The EROO activity in OMBA-treated rat lung microsomes was also significantly inhibited by OMPVT in a dose-dependent manner. The modes of inhibition by DMPVT were non-competitive for all three P450 enzymes. The inhibition of P450 1B1-mediated EROD activity by OMPVT did not show the irreversible mechanism-based effect. The loss of EROD activity in P450 1B1 with OMPVT incubation was not blocked by treatment with the trapping agents such as glutathione, N-acetylcysteine, or dithiothreitol. Taken together, the results suggested DMPVT to be a strong noncompetitive inhibitor of human P450 1 enzymes that should be considered as a good candidate for a cancer chemopreventive agent in humans.

• Journal of Nutrition and Health
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• 제23권1호
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• pp.11-18
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• 1990

Sprague-dawley 숫쥐를 식이지방을 달리하여(I:Soybean oil p/s 4.0, II:beef tallow p/s 0.08) 이유후 8주동안 사육하였다. 이때 I,II군은 각각 기초식이군, 기초식이군에 0.3% butylated hydroxytoluene(BHT)를 첨가신킨 군, 생후 5~7주 사이에 4번의 2-Acetylaminofluorene(2-AAF)를 투여한 군 2-AAF를 투여하고 BHT도 먹인 군으로 나누었다. BHT는 이유 후부터 식이에 섞어 먹였으며 2-AAF를 투여하지 않은 군읜 2-AAF 주사에 의해 얻는 stress와 같은 효과를 주기위해 placebo로 polyethylene glycol 300을 투여하였다. Mixed function oxidase(MFO)계의 효소인 cytochrome p-450, cytochrome b$_5$및 cytochrome p-450 reductase와 과산화지질 등을 측정하였다. 성장기에 2-AAF의 투여는 성장지연을 초래하였으며 지질과산화물은 지방의종류, 2-AAF,BHT 등에 의해 큰 차는 없었다. Cytochrome p-450은 2-AAF에 의해 I-BHT-AAF와 II-AAF군에서 증가되었고 BHT에 의해서는 차이가 나지 않았다. 불포화지방을 먹인경우 cytochrome p-450과 cytochrome p-450 reductase가 2-AAF에 의해 증가되기보다는 오히려 감소하거나 I,II군에 비해 별 차이가 없었는데 2-AAF의 농도와 식이의 불포화도가 높아 세포막이 손상되었기 때문이라 사료된다. Cytochrome $b_5$는 각군 사이에 별 차가 없었다. Cytochrome p-450과 과산화지질(r=0.2475, p<0.05), cytochrome p-450 reductase와 cytochrome $b_5$ (r=0.2475, P<0.05)가 각각 양의 상관관계를 나타내었다. 따라서 2-AAF를 대사시키는 MFO계는 식이지방의 종류 및 BHT의 존재에 따라 영향을 받고, 특히 불포화지방식이인 경우 2-AAF를 대사시킬 수 있는 cytochrome p-450 유도 및 합성능력이 매우 저조함을 알 수 있으며 2-AAF는 어린 쥐의 성장을 지연시켰다.

• The Plant Pathology Journal
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• 제39권6호
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• pp.566-574
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• 2023

The aim of this study was to investigate the regulation of lantipeptide production in Streptomyces globisporus SP6C4, which produces the novel antifungal lantipeptides conprimycin and grisin, and to identify the role of cytochrome P450 (P450) in tis regulation. To investigate the regulation of lantipeptide production, we created gene deletion mutants, including ΔP450, ΔtsrD, ΔlanM, ΔP450ΔtsrD, and ΔP450ΔlanM. These mutants were characterized in terms of their morphology, sporulation, attachment, and antifungal activity against Fusarium oxysporum. The gene deletion mutants showed distinct characteristics compared to the wild-type strain. Among them, the ΔP450ΔlanM double mutant exhibited a recovery of antifungal activity against F. oxysporum, indicating that P450 plays a significant role in regulating lantipeptide production in S. globisporus SP6C4. Our findings highlight the significant role of P450 in the regulation of lantipeptide production and morphological processes in S. globisporus. The results suggest a potential link between P450-mediated metabolic pathways and the regulation of growth and secondary metabolism in SP6C4, thereby highlighting P450 as a putative target for the development of new antifungal agents.

• 한국발생생물학회지:발생과생식
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• 제10권2호
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• pp.127-133
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• 2006

스테로이드 합성효소 중 $17\;{\alpha}-hydroxylase/17,20-lyase(P450_{C17})$는 progesterone을 $17\;{\alpha}-hydroxyprogesterone$을 거쳐 androstenedione으로 변환을 담당하는 효소이다. 양서류 난소에서 스테로이드 합성의 분자적 조절과정의 연구에 사용할 목적으로 북방산 개구리(Rana dybowskii) 난소에서 $P450_{C17}$ cDNA를 클로닝 하였다. 북방산 개구리 난포세포의 cDNA library 검색을 통해 분리된 약 2.5kb의 cDNA는 529개의 아미노산을 가진 단일 번역틀을 가지고 있었다. 개구리 $P450_{C17}$의 아미노산 서열은 Xenopus와는 76%, 닭과는 63%, 그리고 사람과는 약 45%의 동일성을 보여 주였고, 동시에 진화적으로 척추동물에서 매우 잘 보존된 아미노산 서열을 가지고 있었다. 노던 분석에서 개구리의 $P450_{C17}$ 전사체는 난소에서만 2.5kb와 3.6kb 크기의 두 종류가 발견되었다. 그리고 개구리 Rana $P450_{C17}$ cDNA는 비스테로이드 합성 세포인 COS-1세포에서 분명한 $17\;{\alpha}-hydroxylase/17,20-lyase$ 활성을 주었다. 따라서 클로닝된 개구리 $P450_{C17}$ 유전자는 양서류의 난소에서 스테로이드 합성의 분자적 기작을 연구하는데 매우 유용할 것으로 사료된다.

• 한국자원식물학회지
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• 제24권5호
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• pp.584-590
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• 2011

의성종 마늘의 유묘로부터 상처(wound)에 특이적으로 발현되는 cytochrome P450 유전자군의 하나인 P450-Esg cDNA를 탐색하였다. P450-Esg는 1,419 bp의 open reading frame(ORF)을 가지고 473개의 아미노산을 가진 polypeptide를 코딩하는 것으로 나타났다. 국내와 몽골로부터 수집한 12개의 재배종으로 부터 P450-Esg 유사 유전자의 염기서열을 비교한 결과 시작코돈(ATG)에서 472~510 bp 및 1,210~1,240 bp 부위의 염기에서 재배종간에 차이를 보이는 염기서열을 다수 확인하였다. cDNA 1,210~1,240 bp의 부위는 P450 유전자에서 공통적으로 알려진 heme binding domain으로, 각 지역에서 수집된 재배종은 염기서열뿐만 아니라 아미노산 서열에 있어서도 특이적인 변이를 보였다. cDNA 472~510 bp 부위에서 코딩하는 13개 아미노산의 서열은 12개 재배종에서 모두 동일하였으나, 13개 아미노산 중 7개에서 재배종 마다 각각 다른 DNA 염기로 코딩하는 단일 염기다형성(single nucleotide polymorphism)을 보이는 서열을 확인하였다. 이 결과는 다양하게 존재하는 국내외 마늘 재배종을 구분하는 marker로 사용될 것이며, 외국산 마늘에 대한 유전적 우선권을 확보하는 수단으로 사용될 것이다.

• Biomolecules & Therapeutics
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• 제17권2호
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• pp.156-161
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• 2009

The human cytochrome P450 4A11 is the major monooxygenase to oxidize the fatty acids and arachidonic acid. The production of 20-hydroxyeicosatetraenoic acid by P450 4A11 has been implicated in the regulation of vascular tone and blood pressure. Oxidation reaction by P450 4A11 requires its reduction partners, NADPH-P450 reductase (NPR). We report the functional expression in Escherichia coli of bicistronic constructs consisting of P450 4A11 encoded by the first cistron and the electron donor protein, NPR by the second. Typical P450 expression levels of wild type and several N-terminal modified mutants was observed in culture media and prepared membrane fractions. The expression of functional NPR in the constructed P450 4A11: NPR bicistronic system was clearly verified by reduction of nitroblue tetrazolium. Membrane preparation containing P450 4A11 and NPR efficiently oxidized lauric acid mainly to $\omega$-hydroxylauric acid. Bicistronic coexpression of P450 4A11 and NPR in E. coli cells can be extended toward identification of novel drug metabolites or therapeutic agents involved in P450 4A11 dependent signal pathways.

• Toxicological Research
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• 제12권2호
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• pp.155-161
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• 1996

The enzymatic properties for NADPH-P450 reductase domain of a fusion protein between human cytochrome P450 1A1 and rat NADPH-P450 reductase expressed in Escherichia coli were investigated. The fusion plasmid pCW/1A1OR-expressed E. coli membrane showed high NADPH-cytochrome c reductase activity ($830.1\pm 85.8 nmol\cdot min^{-1}\cdot mg protein^{-1}$), while pCW control vector and P 450 1A1 expression vector pCW/1A1 showed relatively quite low activity ($4.35\pm 0.49, 3.27\pm 0.50 nmol\cdot min^{-1}\cdot mg protein^{-1}$, respectively). The kinetic curves for NADPH-cytochrome c reductase followed typical Michaelis-Menten kinetics. The $K_{max}$ and $V_{max}$ for NADPH-dependent reductase activity were $8.24\pm 2.61\mu $and $817.9\pm 60.8 nmol\cdot min^{-1}\cdot mg protein^{-1}$, respectively, whereas those for cytochrome c-dependent reductase activity were $19.97\pm 2.86\mu M$ and $1303.5\pm 67.1 nmol\cdot min^{-1}\cdot mg protein^{-1}$. The reductase activities were also compared with those of rat, porcine and human liver microsomes. The activity of pCW/ 1A1OR-expressed E. coli membrane was 15.2-fold higher than that of rat liver microsome. Treatment with benzo(a)pyrene, 7-ethoxyresorufin and $\alpha$-naphthofiavone which are known as specific substrates or inhibitor for human P450 1A1 increased NADPH-cytochrome c reductase activity of fusion protein in E. coli membrane dose-dependently. These results demonstrate that the membrane topology of fused enzyme may be important for activity of its NADPH-P450 reductase domain.

• 한국환경보건학회지
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• 제19권3호
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• pp.58-63
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• 1993

In order to elucidate the alteration of drug-metabolizing enzymes and mechanism in the animal with hepatic injury and ketosis, the regulation of P450IIE was studied in the rats with heaptic injury caused by CCl$_4$ and with ketosis caused by streptozotocin and high-fat diet. P450IIE expression in liver was examined by the combination of enzyme activities, Western immunoblot, and mRNA Northern blot analyses using specific polyclonal antibody and cDNA probe for P450IIE. Enzyme activity and amounts of immunoreactive P450IIE were rapidly decreased in a time-dependent manner after a single dose of CCl$_4$ . However, the decreases in P450IIE enzyme activity and immunoreactive protein by CCl$_4$ were not accompanied by a decline in its mRNA level. The data thus suggested a post-translational reduction of P450IIE by CCl$_4$. The enzyme activities (aniline hydroxylase) in hepatic microsomes were elevated about 2-3-fold by streptozotocin and feeding with a high fat diet. This increases in enzyme activities were also accompanied by 3-fold increases in immunoreactive P450IIE protein and its mRNA. Our data thus indicated that P450IIE induction during the ketosis appears to be due to pretranslational activation.