• 한국독성학회:학술대회논문집
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• 한국독성학회 2001년도 International Symposium on Dietary and Medicinal Antimutgens and Anticarcinogens
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• pp.199-199
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• 2001

Both hypoxia and insulin induce same target genes including vascular endothelial growth factor (VEGF), glycolitic enzymes and glucose transporters. However these two signals eventually trigger quite different metabolic pathways. Hypoxia induces glycolysis for anaerobic ATP production, while insulin increase glycolysis for lipogenesis and energy storage. Hypoxia-induced gene expression is mediated by Hypoxia-inducible Factorl (HIF-1) that consists of HIF-1 $\alpha$ and $\beta$ subunit.(omitted)

• BMB Reports
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• 제50권9호
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• pp.435-436
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• 2017

Primed human pluripotent stem cells (hPSCs) are highly dependent on glycolysis rather than oxidative phosphorylation, which is similar to the metabolic switch that occurs in cancer cells. However, the molecular mechanisms that underlie this metabolic reprogramming in hPSCs and its relevance to pluripotency remain unclear. Cha et al. (2017) recently revealed that downregulation of SIRT2 by miR-200c enhances acetylation of glycolytic enzymes and glycolysis, which in turn facilitates cellular reprogramming, suggesting that SIRT2 is a key enzyme linking the metabolic switch and pluripotency in hPSCs.

• 미생물학회지
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• 제25권3호
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• pp.189-197
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• 1987

배지성분으로 첨가된 glutamate의 농도가 균의성장고 tylosin 생합성에 미치는 영향을 조사하였다. 그 결과 oxaloacetate를 공동기질로 사용하는 효소의 활성에 의하여 균의 성장과 tylosin의 생합성이 조절됨을 알았다. 즉, citrate synthase와 aspartate aminotransferase의 활성은 균의 성장에 아주 긴요하며 methylmalonyl-CoA carboxytransferase의 활성은 tylosin 생합성에 아주 중요한 효소임을 알았다. Glutamate의 농도는 우의 효소의 활성에 직접적으로 영향을 주고 있음을 알았다.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1996년도 춘계학술대회
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• pp.36-41
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• 1996

Drugs mean not only medicines but also poisons, pesticides, food additives, cosmetics, cleaning agents, environmental pollutants and so on, which are normally considered foreign to the body, It is important to know what happens to these drugs when they get into the body. In the past the metabolic changes of drugs had been referred to as “detoxication mechanism”, but since there are many instances in which drugs are converted in the body to more active substances. Thus, metabolism of drugs is responsible for activation and inactivation of the drugs in the body. The major reactions in drug metabolism are oxidation, reduction, hydrolysis and conjugation. Of these four areas, most of the attention had been focused on the oxidation. Therefore, in contract of ample literatures on drug-oxidizing enzymes, there were relatively few reports on drug-reducing enzymes. In recent years, however, the reduction has received an increasing interest due to its pharmacological or toxicological significance. The present lecture is organized keeping with a focus on drug-reducing enzymes which have been explored by us and by other groups.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 1986년도 추계학술대회
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• pp.506-508
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• 1986

Metabolic activity of inorganic nitrogenous compounds affects not only microbial growth but also metabolite production in fermentation technology. We have worked on the enzymes participating in ammonia assimulation of some fermentation bacteria. This paper summarizes the results on glutamine synthetase and its application in practical field. Glutamine synthetase (L-glutamate:ammonia ligase, EC. 6.3.1.2) catalyzes the formation of glutamine from glutamate and ammonia at the expense of cleavage of ATP and inorganic phosphate. The enzyme plays a dual role in nitrogen metabolism in bacteria; it is a key enzyme not only in the biosynthesis of various compounds through glutamine but also in the regulation of synthesis of some enzymes involved in the metabolism of nitrogenous compounds. The detailed works with the Eschericia coli and other enterobacterial enzymes revealed that glutamine synthetase is controlled by the following complex of mechanisms: (a) feedback inhibition by end products, (b) repression and derepression of enzyme synthesis, (c) modulation of enzyme activity in response to divalent cation and (d) covalent modification of enzyme protein by adenylylation and its cascade control. Comparative studies have also been made on the enzymes from other organisms.

• Biomolecules & Therapeutics
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• 제12권3호
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• pp.185-188
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• 2004

The purpose of this study is to evaluate the effect of cigarette smoke condensate (CSC) on toxification/detoxification metabolic pathway in primary cultured rat hepatocytes. We measured the activities of cytochrome P450 monooxygenases (CYP450s) and UDP-glucuronyltransferase, sulfotransferase and glutathione-S-transferase in CSC-treated rat hepatocytes. CSC significantly increased the activities of hepatic CYP4501A1 and CYP4501A2 to 7.5 fold and 1.6 fold respectively, compared with control level. However, CSC did not affect the activities of conjugation enzymes. We a1so examined if treatment of CSC could change thc cytotoxicity of acetaminophen (AA) through modulation of metabolizing enzymes. In rat hepatocytes, pretreatment with CSC potentiated the cytotoxicity of AA. This result indicates that potentiation of AA toxicity by CSC pretreatment may be related to induction of CYP4501A1 and CYP4501A2.

• 대한유전성대사질환학회지
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• 제5권1호
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• pp.76-87
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• 2005

Various disorders cause hyperammonemia during childhood. Amongthem are those caused by inherited defects in urea synthesis and related metabolic pathways. These disorders can be grouped into two types: disorders of the enzymes that comprise the urea cycle, and disorders of the transporters or metabolites of theamino acids related to the urea cycle. Principal clinical features of these disorders are caused by elevated levels of blood ammonium. Additional disease-specific symptoms are related to the particular metabolic defect. These specific clinical manifestations are often due to an excess or lack of specific amino acids. Treatment of urea cycle disorders and related metabolic diseases consists of nutritional restriction of proteins, administration of specific amino acids, and use of alternative pathways for discarding excess nitrogen. Although combinations of these treatments are extensively employed, the prognosis of severe cases remains unsatisfactory. Liver transplantation is one alternative for which a better prognosis is reported.

• Journal of Microbiology
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• 제43권6호
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• pp.475-486
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• 2005

Fungal secondary metabolites constitute a wide variety of compounds which either playa vital role in agricultural, pharmaceutical and industrial contexts, or have devastating effects on agriculture, animal and human affairs by virtue of their toxigenicity. Owing to their beneficial and deleterious characteristics, these complex compounds and the genes responsible for their synthesis have been the subjects of extensive investigation by microbiologists and pharmacologists. A majority of the fungal secondary metabolic genes are classified as type I polyketide synthases (PKS) which are often clustered with other secondary metabolism related genes. In this review we discuss on the significance of our recent discovery of chalcone synthase (CHS) genes belonging to the type III PKS superfamily in an industrially important fungus, Aspergillus oryzae. CHS genes are known to playa vital role in the biosynthesis of flavonoids in plants. A comparative genome analyses revealed the unique character of A. oryzae with four CHS-like genes (csyA, csyB, csyC and csyD) amongst other Aspergilli (Aspergillus nidulans and Aspergillus fumigatus) which contained none of the CHS-like genes. Some other fungi such as Neurospora crassa, Fusarium graminearum, Magnaporthe grisea, Podospora anserina and Phanerochaete chrysosporium also contained putative type III PKSs, with a phylogenic distinction from bacteria and plants. The enzymatically active nature of these newly discovered homologues is expected owing to the conservation in the catalytic residues across the different species of plants and fungi, and also by the fact that a majority of these genes (csyA, csyB and csyD) were expressed in A. oryzae. While this finding brings filamentous fungi closer to plants and bacteria which until recently were the only ones considered to possess the type III PKSs, the presence of putative genes encoding other principal enzymes involved in the phenylpropanoid and flavonoid biosynthesis (viz., phenylalanine ammonia-lyase, cinnamic acid hydroxylase and p-coumarate CoA ligase) in the A. oryzae genome undoubtedly prove the extent of its metabolic diversity. Since many of these genes have not been identified earlier, knowledge on their corresponding products or activities remain undeciphered. In future, it is anticipated that these enzymes may be reasonable targets for metabolic engineering in fungi to produce agriculturally and nutritionally important metabolites.

• Archives of Pharmacal Research
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• 제27권7호
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• pp.781-789
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• 2004

The effect of 1,8-cineole on cytochrome P450 (CYP) expression was investigated in male Sprague Dawley rats and female BALB/c mice. When rats were treated orally with 200, 400 and 800 mg/kg of 1,8-cineole for 3 consecutive days, the liver microsomal activities of benzy-loxyresorufin- and pentoxyresorufin-D-dealkylases and erythromycin N-demethylase were dose-dependently induced. The Western immunoblotting analyses clearly indicated the induction of CYP 2B1/2 and CYP 3A1/2 proteins by 1,8-cineole. At the doses employed, 1,8-cineole did not cause toxicity, including hepatotoxicity. Subsequently, 1,8-cineole was applied to study the role of metabolic activation in thioacetamide-induced hepatotoxicity and/or immunotoxicity in animal models. To investigate a possible role of metabolic activation by CYP enzymes in thioacetamide-induced hepatotoxicity, rats were pre-treated with 800 mg/kg of 1,8-cineole for 3 days, followed by a single intraperitoneal treatment with 50 and 100 mg/kg of thioacetamide in saline. 24 h later, thioacetamide-induced hepatotoxicity was significantly potentiated by the pretreatment with 1,8-cineole. When female BALB/c mice were pretreated with 800 mg/kg of 1,8-cineole for 3 days, followed by a single intraperitoneal treatment with 100 mg/kg of thioace-tamide, the antibody response to sheep red blood cells was significantly potentiated. In addition, the liver microsomal activities of CYP 2B enzymes were significantly induced by 1,8-cineole as in rats. Taken together, our results indicated that 1,8-cineole might be a useful CYP modulator in investigating the possible role of metabolic activation in chemical-induced hepato-toxicity and immunotoxicity.

• 환경생물
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• 제20권2호
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• pp.173-179
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• 2002

N-nitrosoethylurea(NEU)에 의한 지질 과산화물의 함량 변화와 알데히드 대사효소 및 항산화효소의 활성변화를 쥐 간세포에서 측정하였다. 알데히드 대사효소로는 alcohol dehydrogenase와 aldehyde dehydrogenase가 사용되었고 항산화효소로는 glutathione transferase, superoxide dismutase, glutathione reductase와 catalase가 사용되었다. 쥐 간세포에 다양한 농도의 NEU를 처리한 후 지질 과산화물의 함량변화를 측정하였다. 그 결과 6.25mM NEU에 의하여 지질 과산화물의 함량이 최대 2.5배 증가하였다. Alcohol dehydrogenase의 활성은 NEU처리에 의하여 대조군보다 최대 2.3배 증가하였고 aldehyde dehydrogenase의 활성은 약 2배 증가하였다. 전암성 병변의 지표로 이용되는 glutathione transferase와 catalase의 경우 NEU처리에 의한 활성증가가 미미하였다. 그러나 superoxide dismutase의 활성은 최대 1.5배 증가하였고, glutathione reductase의 활성은 약 3배 증가하였다. 그러므로 superoxide dismutase와 g1utathione reductase의 활성증가가 NEU의 독성에 대한 세포내 항산화 방어과정에서 중요한 역할을 할 것으로 추측된다