• 생명과학회지
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• 제19권7호
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• pp.852-858
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• 2009

호흡전자전달계의 cytochrome bc$_1$ complex 또는 cytochrome c oxidase가 기능을 하지 않는 Rhodobacter sphaeroides mutant 내에서 pyridine nucleotide[NAD(P)H와 NAD(P)$^+$]의 농도와 redox 상태는 wild type과 비교할 때 큰 변화가 없었다. 높은 산소분압 조건에서 키운 Rhodobacter sphaeroides cbb$_3$ oxidase mutant 내에서 PrrBA two-component system에 의해서 조절되는 puf 오페론의 발현은 pyridine nucleotide나 전자전달계의 ubiquinone/ubiquinol pool의 redox 상태의 변화에 의해 유도된 것이 아니다. R. sphaeroides cytochrome bc$_1$ complex mutant를 이용하여 광합성기구 합성에 대한 cbb$_3$ cytochrome c oxidase의 억제 효과는 ubiquinone/ubiquinol pool의 redox 변화에 의해 간접적으로 일어나는 것이 아님을 증명하였다.

• 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.

• Bulletin of the Korean Chemical Society
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• 제34권2호
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• pp.406-410
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• 2013

Tetrahyropapaveroline (THP) is compound derived from dopamine metabolism and is capable of causing dopaminergic neurodegenerative disorder, such as Parkinson's disease (PD). The aim of this study was to evaluate the potential of THP to cause oxidative damage on the structure of cytochrome c (cyt c). Our data showed that THP led to protein aggregation and the formation of carbonyl compound in protein aggregates. THP also induced the release of iron from cyt c. Reactive oxygen species (ROS) scavengers and iron specific chelator inhibited the THP-mediated cyt c modification and carbonyl compound formation. The results of this study show that ROS may play a critical role in THP-induced cyt c modification and iron releasing of cyt c. When cyt c that has been exposed to THP was subsequently analyzed by amino acid analysis, lysine, histidine and methionine residues were particularly sensitive. It is suggested that oxidative damage of cyt c by THP might induce the increase of iron content in cells and subsequently led to the deleterious condition. This mechanism is associated with the deterioration of organs under neurodegenerative disorder such as PD.

• Toxicological Research
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• 제11권2호
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• pp.215-221
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• 1995

This paper examines the effects of dietary polyunsaturated fatty acid/saturated fatty acid (p/s) ratios and butylated hydroxytoluene (BHT) on the hepatic microsomaI mixed-function oxidase sy. stem in 2~acetylaminofiuorene (2-AAF) treated rats. Sprague-Dawley male rats were fed the diet of beef tallow (p/s 0.08), beef tallow plus soybean oil (p/s 1.0), and soybean oil (p/s 4.0) at the level of 15%fat and with or without 0.3% BHT. After 2-AAF was injected twice at the ages of 23 and 27 weeks, cholesterol/phospholipid molar ratio, thiobarbituric acid reactive substances (TBARS) level, cytochrome P450, cytochrome $b_5$, NADPH-cytochrome $b_5$, and NADPH-cytochrome c reductase activity were measured from isolated hepatic microsomal fractions. In the beef tallow (p/s 0.08) and beef tallow plus soybean oil (p/s 1.0) groups, cholesterol/phospholipid molar ratio showed decreasing tendency by 2-AAF and BHT. Cytochrome P-450 content was decreased in the group of soybean oil (p/s 4.0) and NADPH-cytochrome c reductase activity was increased by 2-AAF and BHT in all the dietary groups. While TBARS levels were increased by 2-AAF in all the dietary groups, they were reduced by BHT in the soybean oil (p/s 4.0) group. These results suggest that long term intake of soybean oil (p/s 4.0) diet induced changes in the nature of microsomal membrane and induced less cytochrome P-450, low level feeding of BHT increased cytochrome c reductase activity and lowered microsomal lipid peroxidation levels, which were increased by 2-AAF treatment.

• 미생물학회지
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• 제30권6호
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• pp.533-538
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• 1992

Methylobacterium extorquens AM1 이 pH 5.5 와 7.0 에서 메탄올을 이용하여 성장할 때의 세대 시간은 각각 25 시간과 8.3 시간이었다. pH 7.0 에서 성장한 세균들은 모두 지수성장기 중기에서 가장 높은 methanol dehydrogenase (MDH_) 의 활성을 나타내었고, MDH 함유량은 성장시기에 따른 변화를 보이지 않았다. 세포내 cytochrome c 는 정체기에서 높게 나타났고 pH 7.0 에서 성장한 세균에 더 많이 존재하였다. Putrescine 또는 spermidine 이 첨가된 pH 5.5 의 배지에서 성장한 세균에 더 많이 존재하였다. Putrescine 또는 spermidine 이 첨가된 pH 5.5 의 배지에서 성장한 세균에서는 putrescine 의 함량은 증가하였으나 spermine 의 함량은 감소하였고 spermidine 의 함량에는 변화가 없었다. Spermine 을 첨가한 배지에서 성장한 세균에서는 폴리아민함량에 변화가 없었다. Putrescine 또는 spermidine이 첨가된 배지에서 성장한 세균에서 MDH 와 hydroxypyruvate reductase 의 활성이 증가되었고 MDH 와 cytochrome c 의 함량에는 변화가 없었다. 폴리아민은 invitro 상태에서 MDH 와 hydroxypyruvate reductase 의 활성을 증가시키지 않았다.

• Archives of Pharmacal Research
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• 제25권3호
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• pp.375-380
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• 2002

Cytochrome P4501A2 (CYP1A2) is a member of the cytochrome P450 family of isozymes involved in the phase I drug metabolism of vertebrates. CYP1A2 is responsible for the activation of a number of aromatic amines to mutagenic and carcinogenic forms. Thus, the level of CYP1A2, which varies among different populations, may determine an individual's susceptibility to these chemicals. We have previously reported on the importance of a cis element named PRB (protected region B) in the regulation of human Cytochrome P4501A2 (CYP1A2) gene, which appeared to act as a positive regulatory element. Closer examination of the PRB sequence (-2218 to -2187 bp) revealed a putative AP-1 binding site, TGACTAA, at -2212 bp (Chung and Bresnick, 1997). To elucidate the role of AP-1 in CYP1A2 regulation, we transiently overexpressed c-Jun and c-Fos transcription factors in human hepatoma HepG2 cells, and examined their influence on the CYP1A2 promoter activity by reporter gene assays. Cotransfection of the c-Jun and the c-Fos expression vectors increased the induced transactivation by five to six fold from the CYP1A2 promoter constructs. However, deletion of the PRB element did not affect the degree of activation by the c-Jun and the c-Fos. Therefore, it is unlikely that the c-Jun and the c-Fos activate the CYP1A2 promoter through this AP-1 consensus-like sequence in the PRB region.

• 대한의생명과학회지
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• 제7권2호
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• pp.65-70
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• 2001

We have carried out PCR reactions to investigate if cytochrome P450 (P450) enzymes (1A1, 1A2, 2C8, 2E1 and 3A4), which are well hewn to be the key enzymes in detoxification process and/or synthesis of steroids in the liver, are expressed in the human brain, too. P450 1A1, 2C8 and 2E1 were expressed clearly. However, P450 1A2 and 3A4 were not detectable. Their expression levels in the human brain could be extremely low or they were not expressed at all. One base substitution at nucleotide 290 (A->G) was identified in P450 1A1. It is suspected to be an individual polymorphism. Our results should contribute to the better understanding of the role of cytochrome P450 enzymes in the human brain.

• Journal of Microbiology and Biotechnology
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• 제12권3호
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• pp.476-482
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• 2002

Methanol dehydrogenase (MDH) and c-type cytochromes from marine methanol-oxidizing bacterium, Methylophaga sp. MP, were purified and characterized. The native MDH had a molecular mass of 148 kDa and its isoelectric point was 5.5. Two c-type cytochromes, $c_L\;and\;c_H$, were found, and their isoelectric points were 3.4 and 8.0, respectively. The purified MDH had higher thermal stability than that of the other soil methylotrophic bacteria. The electron flow rate from MDH to cytochrome $c_L$was higher than that from MDH to cytochrome $c_H$, indicating that the physiological primary electron acceptor for MDH is cytochrome $c_L$. The electron transfer from MDH to phenazine ethosulfate (PES, artificial electron acceptor) in the two dye (PES/DCPIP)-linked assay system was not inhibited by NaCl, whereas the electron flow from MDH to cytochrome $c_L$ in the cytochrome/DCPIP-linked assay system was suppressed significantly by NaCl. Metal chelating agents such as EDTA showed the same effects on the MDH activity.

• Archives of Pharmacal Research
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• 제8권3호
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• pp.119-132
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• 1985

The apparent effectiveness of 1-naphthyl-N-methyl carbamate (carbaryl) against a wide variety of insects motivated the study of its mammalian toxicity. In this toxicological study of carbaryl, mature male rats inhaled carbaryl at a mean concentration of 112mg, 168mg and 224 mg/$m^{3}$ for one hour. After inhalation, pentobarbital sleeping time, Nadph-cytochrome c reductase activity, cytochrome p-450 and protein content in liver microsomes, various tissue residues, cholinesterase inhibition in plasma and histopathological findings at autopsy were observed. The pentobarbital sleeping time was prolonged in rats inhaled with carbaryl for one day while the sleeping time was shortened in the 3 days inhaled group. The changes of cytochrome p-450 content and NADPH-cytochrome c reductase activity exhibited biphasic response showing the decrease in the one day inhaled group and the increase in the 3 days inhaled group. The marked depression of plasma ChE activity was observed in rats inhaled with carbaryl at 112 mg/$m^{3}$, however no more progressive effect was observed at the higher concentration of the compound. The main observations in histopathological finding were ciliary detachment, epithelial swelling and subepithelial inflammatory cellular infiltration in trachea due to the irritation.

• Toxicological Research
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• 제17권3호
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• pp.215-223
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• 2001

카드뮴의 주요한 표적장기이며 카드뮴이 만성 및 급성 폭로시 축적되는 가장 중요한 장기인 간의 세포독성을 Hepalclc7세포에서 caspases및 Bax단백질의 활성과 발현 그리고 미토콘드리아 세포막 전위 변화(MPT) 등을 조사하여 다음과 같은 결과를 얻었다. 1. 카드뮴은 농도의존적으로 간세포인 Hepalclc7 세포의 생존율을 감소시켰다. 2. 카드뮴을 농도별로 처리하였을 때 100 M 이상의 농도에서 세포사멸의 특징중의 하나인 DNA분절현상을 확인하였다. 3. 카드뮴 처리 후 caspase-3, caspase-8, caspase-9 의 활성변화를 조사한 결과 caspase-3,-9 pretease 활성이 시간이 경과함에 따라 증가하였다. 4. 카드뮴 처리 후 cytochrome c가 세포질내로 방출되었고 이는 caspase-9 proteas의 활성화를 유도하였다. 5. 카드뮴 처리 후 Bax가 세포질에서 미토콘드리아로 이동하여 cytochrome c의 세포질내로의 방출에 관여하였다. 6. 카드뮴 처리시 미토콘드리아 세포막 전위차의 감소를 JC-1 형광염색을 통하여 확인하였다. 이상의 결과는 카드뮴에 의한 Hepalclc7 세포사멸의 신호전달기전은 세포질내에 있는 Bax가 미토콘드리아로 이동, cytochrome c의 세포질내로의 방출, 그리고 caspase-3, 9 pretease 활성화를 의해서 매개되는 것으로 판단된다. 또한 Bax 단백질의 발현변화가 미토콘드리아의 기능변화에 기여하였으리라 사료된다.