• 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.

• Toxicological Research
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• 제18권3호
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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.

• BMB Reports
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• 제30권1호
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• pp.73-79
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• 1997

This study was designed to investigate the effects of dietary garlic powder on cytochrome P450 enzymes and membrane stability in murine hepatocarcinogenesis initiated by diethylnitrosamine (DEN). Male Sprague-Dawley rats received a single intraperitoneal injection of DEN (200 mg/kg body wt) dissolved in saline. After 2 weeks on a basal diet, animals were fed diets containing 0. 0.5. 2.0. or 5.0% garlic powder for 6 weeks, and were subjected to two-thirds partial hepatectomy. The areas of placental glutathione S-transferase (GST-P) positive foci were inhibited in rats fed with garlic diets. GST-P is the most effective marker for DEN-initiated lesions. Hepatic microsomal lipid peroxidation was significantly decreased in rats fed with 2.0 and 5.0% garlic powder diets compared with that observed in the control animals and hepatic microsomal glucose 6-phosphatase (G6Pase) activity was found to increase significantly in rats fed 0.5 and 2.0% garlic powder diets. Thus as little as 0.5% garlic powder has a positive effect on the stability of hepatic microsomal membranes. p-Nitrophenol hydroxylase (PNPH) activity and the level of cytochrome P450 2E1 protein in the hepatic microsomes from rats fed diets containing 2.0 and 5.0% garlic powder were much lower than those of control microsomes. Rats fed 5.0% garlic powder diets exhibited the lowest P450 2E1 activity and protein levels among groups. Pentoxyresorufin O-dealkylase activity and immunoblot (cytochrome P450 2B1) analyses were not different between groups. However, the levels of cytochrome P450 1A1/2 protein in rats fed 0.5 and 2.0% garlic powder were significantly induced compared to controls. These results suggest that 2.0% garlic powder is effective in inhibiting the areas of GST-P positive foci, modulating certain isoforms of cytochrome P450 enzymes and stabilizing the hepatic microsomal membrane. Thus, the selective modification of cytochrome P450 enzymes and membrane stability by dietary garlic powder may influence areas of GST-P positive foci and chemoprevention of post-initiation of rat hepatocarcinogenesis.

• 사상체질의학회지
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• 제17권2호
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• pp.64-73
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• 2005

1. Objectives The purpose of this study was to investigate the effects of the enzyme activity of Palmulgunja-tang with administered orally solution on cytochrome P450 isozyme 2. Methods This study was carried on through following methods. We treated the rat with the {3-naphthoflavone (${\beta}NF$) of 80mg/kg for 3 days i.p injection. Firstable, microsomal protein was separated and total intracellular protein test was done. Then GOT and GPT were measured and assay of cytochrome P450 IAI/2 enzyme activity was performed according to the method of EROD and MROD. (Ethoxyresorufin-O-deethylase(EROD) activity was used to measure cytochrome P450 lAI activity and methoxyresorufin O-demethylase(MROD) activity was used to measure cytochrome P450 lA2 activity. ) 3. Results and Conclusions 1) PGT recovered the liver damage on ${\beta}NF$ inducible CYP IAI/2 by pre-post and high-low condition. 2) At concentration of post-treated 50mg!kg of PGT, the inhibiting of $\betaNF$ metabolites to liver of rat cytochrome P450 lAl was inhibited by 53.0% respectively. 3) PGT showed 36.0% inhibition of ${\beta}NF$-induced lA2 activity at the concentration post-treated 50mg/kg.

• Journal of Nutrition and Health
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• 제29권7호
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• pp.689-702
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• 1996

The purpose of this experiment was to compare the effects of tryptophan administration on nutritional status of female rats which consumed reserpine and 6% casein diet with different carbohydrate contents(87%, 65%, 44% respective). Final body weight, body weight gain, FER, plasma amino acid concentration and microsomal cytochrome P 450 content in liver were measured and microscopic structure of hepatocytes was observed. In low-protein diet, the higher the carbohydrate content of diet was, the lower the damage was in the rat's liver. Tryptophan administration after dose of reserpine induced more effective recovery from liver damage of rats in high carbohydrate diet group than that in low carbohydrate diet group. In conclusion, the general nutritional assessments such as final body weight and body weight gain provided better estimate of the degree of structural changes in hepatocytes than functional assessment such as plasma amino acid concentration or liver microsomal cytochrome P450.

• Journal of Microbiology and Biotechnology
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• 제19권12호
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• pp.1612-1616
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• 2009

Isoflavonoids are a class of phytoestrogens. Isoflavonone synthase (IFS) is responsible for the conversion of naringenin to genistein. IFS is a cytochrome P450 (CYP), and requires cytochrome P450 reductase (CPR) for its activity. Additionally, the majority of cytochrome P450s harbor a membrane binding domain, making them difficult to express in Escherichia coli. In order to resolve these issues, we constructed an inframe fusion of the IFS from red clover (RCIFS) and CPR from rice (RCPR) after removing the membrane binding domain from RCIFS and RCPR. The resultant fusion gene, RCIFS-RCPR, was expressed in E. coli. The conversion of naringenin into genistein was confirmed using this E. coli transformant. Following the optimization of the medium and cell density for biotransformation, $60\;{\mu}M$ of genistein could be generated from $80\;{\mu}M$ of naringenin. This fusion protein approach may be applicable to the expression of other P450s in E. coli.

• 한국토양비료학회지
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• 제40권4호
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• pp.274-279
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• 2007

4 종류의 폐기물(생활하수오니, 공단하수오니, 피혁오니, 주정오니)과 대조구로서 돈분퇴비가 지렁이에게 미치는 독성을 평가하기 위하여 대표적인 유해성 평가 biomarker 3종류 (acetylcholinesterase, cytochrome $P_{450}$, heat shock protein 70)를 사용하였다. 유기성 폐기물에 대한 acetylcholinesterase의 활성은 돈분퇴비의 경우 활성이 약간 촉진된 반면 생활하수오니, 공단하수오니, 피혁오니, 주정오니는 영향을 미치지 않았다. Cytochrome $P_{450}$의 활성은 공단하수오니와 피혁오니는 활성을 억제하였고 생활하수오니, 주정오니, 돈분퇴비는 영향을 미치지 않았다. 또한 Hsp70의 발현량은 증류수보다 돈분퇴비는 1.9배, 주정오니는 3.0배, 생활하수오니는 3.3배, 공단오니는 4.4배, 피혁오니는 4.7배 순으로 지렁이 (Eisenia fetida)에게 스트레스를 많이 주었다. 이상의 결과로부터, 4 종류의 폐기물(생활하수오니, 공단하수오니, 피혁오니, 주정오니)은 돈분퇴비보다 독성이 강한 것으로 판단하였다. 또한 AChE, Cytochrome $P_{450}$과 Hsp70은 추후 유기성 폐기물의 유해성을 모니터링하기에 적합한 biomarker로서 가치가 있다고 생각한다.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1995년도 제3회 추계심포지움
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• pp.153-155
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• 1995

To investigate the mechanism of the regulation of cytochrome P450IAl, the 5'-flanking region of a trout cytochrome P4501Al was cloned into the CAT basic expression vector at HindⅢ site. This trout Cytochrome P450IAl upstream DNA containing CAT construct was transfected into Hepa-1 cells .3MC treatment to hepa I cells transfected with trout P450IAl-CAT construct increased CAT protein and mRNA by 2.81 fold when it was compared with that of control. This increase CAT protein and mRNA was decreased by concomitantly treated flavonoids and aminopyrine. The level of CAT protein was 29.2-58.0% of 3MC stimulated CAT protein.

• 한국식품영양과학회지
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• 제28권3호
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• pp.638-645
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• 1999

This study was done to investigate effects of ${\gamma}$ irradiated beef feeding on the formation of gluta thione S transferase placental form positive(GST P+) foci, lipid peroxidation, cytochrome P450 system and microsomal glucose 6 phosphate activity in diethylnitrosamine(DEN) initiated rat hepatocarci nogenesis. Weaning Sprague Dawley male rats were fed the diet containing ${\gamma}$ irradiatied ground beef at the dose of 0, 3, 5kGy as a 20% of protein source for 8 weeks. One week after feeding, rats were intraperitoneally injected twice with a dose of DEN(50mg/kg BW). As a promoter, 0.05% phenobarbital was fed in drinking water from one week after DEN treatment until the end of experiment. At the end of 8th week, rats were sacrificed and hepatic GST P+ foci, microsomal malondialdehyde(MDA) and conjugated diene contents were determined. In addition, cytochrome P450 content and the activities of NADPH cytochrome P450 reductase and glucose 6 phosphatase were also measured. There was no significant effect by gamma irradiation on microsomal MDA content, conjugated diene, cytochrome P450 content and activities of NADPH cytochrome P450 reductase and glucose 6 phosphatase. However with DEN treatment, microsomal MDA content and conjugated diene contents were significantly changed. Cytochrome P450 content was also significantly increased while microsomal glucose 6 phophatase activity was significantly decreased with DEN treatment. However activity of NADPH cytochrome P450 reductase was not affected. An interesting finding in this study was that the number and area of hepatic GST P+ foci of the rats fed gamma irradiated beef were significantly(p<0.05) lower than those of the control. Such a lowering effect on GST P+ foci formation was highest at the dose of 3kGy than others. Overall results suggest that the consumption of low dose of gamma irradiated beef does not affect the formation of lipid peroxide, cytochrome P450 system and membrane stability.

• Preventive Nutrition and Food Science
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• 제2권4호
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• pp.328-332
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• 1997

The ripe fruit of Hass avocado contains one of the highest elvels of cytochrome P-450 protein found in the plant kingdom. To determine whether wounded roots of avocado contain P-450 protein, the roots of avocado were wounded by slicing, and then allowed to incubate in sealed plastic bags, in 0.4M mannitol, and in the solution to make protoplast preparation containing cellulysin and macerase during the specified times. The microsomal proteins were extracted from the samples, separated by SDS-PAGE, and then subjected to Western blot analysis using polyclonal antibodies which are generated against the CYP71A1 protein. wounded roots in sealed bags produced CYP71A1 within 6 hours after cutting, and those in 0.4M mannitol did not produce CYP71A1 even after 72 hours, but those in the protoplast preparation by cellulysin and macerase induced and produced CYP71A was induced in only 24 hours. These results indicate that CYP 71A1 plays a role for wound healing for root tissue o avocado, and would-inducible P-450 protein was not detected in the mannitol solution by preventing a synthesis of ethylene in a liquid state, but the softening of tissues by cellulysin and macerase to make protoplast preparation was involved in an activation of CYP 71A1 even in the liquid state.