• 한국표면공학회지
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• 제25권3호
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• pp.150-157
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• 1992

A recovery process of pure alumina powder from the wasted aluminum etching solution of electrolytic condenser works was studied. The possibility of this process was considered in the basis of thermodynamic data nad physico-chemical properties for the recovered materials were tested. In order to obtain pure alumina, Fe3+ and Cu2+ in the solution as impurities were solvent-extracted, respectively, and then, Al3+ was precipitated by changing the pH of the solution. As the results, more than 99.9% of Al3+ in the solution was recovered by the precipitation method. The weight of the precipitate was reduced to about 65 wt.% of the original one by calcination and the sizes of the recovered powders were in order of 3-5$\mu\textrm{m}$. The precipitates were transformed to $\alpha$-Al2O3 at the calcination temperature about 120$0^{\circ}C$.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.161.1-161.1
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• 2003

NAD(P)H:quinone oxidoreductase (quinone reductase: QR: EC1.6.99.2), a cytosolic FAD-containing flavoprotein, form one of the important component of the phase II drug-metabolizing enzyme systems. It is found in all mammalian species tested and is expressed in many organs including the liver. QR catalyses two-electron reduction of qui nones to hydroquinones thereby suppresses the formation of superoxide anion radical. (omitted)

• Toxicological Research
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• 제17권
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• pp.299-304
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• 2001

Xenobiotics and their reactive intermediates bind to cellular macromolecules and/or generate oxidative stress. which provoke deleterious effects on the cell function. Induction of xenobiotic-biotrans-forming enzymes and antioxidant molecules is an important defense mechanism against such insults. A group of genes involved in the defense mechanism. e.g. genes encoding glutathione S-transferases. NAD(P)H: quinone oxidoreductase, UDP-glucuronosyltransferase (UDP-GT) and ${\gamma}$-glutamylcysteine synthetase (GGCS). have a common regulatory sequence, Antioxidant or Electrophile Responsive Element (ARE/EpRE). Recently. Nrf2. discovered as a homologue of erythroid transcription factor p45 NF-E2, was shown to bind ARE/EpRE and induce the expression of these defense genes. Mice that lack Nrf2 show low basal levels of expression and/or impaired induction of these genes. which makes the animals highly sensitive to xenobiotic toxicity. Indeed. we show here that nrf2-deficient mice had a higher mortality than did the wild-type mice when exposed to acetaminophen (APAP). Detailed analyses of APAP hepatotoxicity in the nrf2 knockout mice indicate that a large amount of reactive APAP metabolites was generated in the livers due to the impaired basal expression of two detoxifying enzyme genes, UDP-GT (Ugt1a6) and GGCS. while the cytochrome P450 content was unchanged. Thus. the studies using the nrf2 knockout mice clearly demonstrate significance of the expression of Nrf2-regulated enzymes in protection against xenobiotic toxicity.

• BMB Reports
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• 제48권11호
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• pp.609-617
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• 2015

NAD(P)H:quinone oxidoreductase (NQO1), an obligatory two-electron reductase, is a ubiquitous cytosolic enzyme that catalyzes the reduction of quinone substrates. The NQO1- mediated two-electron reduction of quinones can be either chemoprotection/detoxification or a chemotherapeutic response, depending on the target quinones. When toxic quinones are reduced by NQO1, they are conjugated with glutathione or glucuronic acid and excreted from the cells. Based on this protective effect of NQO1, the use of dietary compounds to induce the expression of NQO1 has emerged as a promising strategy for cancer prevention. On the other hand, NQO1-mediated two-electron reduction converts certain quinone compounds (such as mitomycin C, E09, RH1 and β-lapachone) to cytotoxic agents, leading to cell death. It has been known that NQO1 is expressed at high levels in numerous human cancers, including breast, colon, cervix, lung, and pancreas, as compared with normal tissues. This implies that tumors can be preferentially damaged relative to normal tissue by cytotoxic quinone drugs. Importantly, NQO1 has been shown to stabilize many proteins, including p53 and p33ING1b, by inhibiting their proteasomal degradation. This review will summarize the biological roles of NQO1 in cancer, with emphasis on recent findings and the potential of NQO1 as a therapeutic target for the cancer therapy.

• Animal cells and systems
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• 제11권1호
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• pp.17-22
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• 2007

The effects of antimetabolite 6-AN (6-amino-nicotinamide) on viability and morphology of L6 myoblast cells have been investigated. 6-AN ($100{\mu}M$) induced a time-dependent decrease in cell viability with respect to the untreated control cells. Following 6-AN administration the viability rate started to decline sharply, reaching about 23% of the untreated control cells at 48 h. Inverted phase-contrast microscopy revealed that 6-AN caused characteristic morphological changes such as irregularly elongated and stellate shape of cells, round-shaped nucleus, cytoplasmic vacuolization, irregular cell arrangements and formation of large spaces among cell clusters. The concentrations of ATP and $NAD^{+}$ in the 6-AN treated cells were significantly lower (p < 0.01) than those of the untreated control cells. In contrast, the concentration of AMP was significantly increased by the 6-AN treatment. Activities of catalase, superoxide dismutase and glutathione peroxidase in 6-AN treated cells were significantly higher (p < 0.01) than those of the untreated control cells. The activities of glyceraldehyde-3-phosphate dehydrogenase in 6-AN treated cells were significantly lower (p < 0.01) than those of the untreated control cells. The results suggest that 6-AN caused marked reduction of cell viability and alterations of some important metabolites and enzymes.

• Journal of Pharmaceutical Investigation
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• 제21권2호
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• pp.67-71
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• 1991

A simple and sensitive method was developed for the quantification of free and conjugated bile acids in bezoar without prior hydrolysis. $3{\alpha}-Hydroxy$ bile acids are first oxidized to 3-keto bile acids in the reaction catalyzed by $3{\alpha}-hydroxysteroid$ $dehydrogenase(3{\alpha}-HSD)$. During this oxidative reaction, an equimolar quantity of nicotinamide adenine dinucleotide(NAD) is reduced to NADH and subsequently oxidized to NAD with concomitant reduction of nitrotetrazolium blue(NTB) to diformazan by the catalytic action of diaphorase. The diformazan has an absorbance maximum at 540 nm. The intensity of the color produced is directly proportional to bile acids concentration in the bezoar extracts. The optimum conditions for the enzymatic reaction such as effects of reaction time, reaction temperature and pH, and stability were investigated. Calibration plots for the sodium chelate observed to be linear and intra-, inter-assay analytical recovery of bile acids averaged $97.65{\pm}3.4%(S.D.)$. Therefore, it is considered that the quality control of total bile acids from bezoar or bezoar-containing liquid preparation using this simple and sensitive assay system will be acceptable. Also current bezoars and bezoar-containing liauid preparations were examined their total bile acids from this method.

• 한국초지조사료학회지
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• 제36권3호
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• pp.243-247
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• 2016

Arsenic (As) is a toxic element that easily taken up by plants root. Several toxic forms of As disrupt plant metabolism by a series of cellular alterations. In this study, we applied annealing control primer (ACP)-based reverse transcriptase PCR (polymerase chain reaction) technique to identify differentially expressed genes (DEGs) in alfalfa roots in response to As stress. Two-week-old alfalfa seedlings were exposed to As treatment for 6 hours. DEGs were screened from As treated samples using the ACP-based technique. A total of six DEGs including heat shock protein, HSP 23, plastocyanin-like domain protein162, thioredoxin H-type 1 protein, protein MKS1, and NAD(P)H dehydrogenase B2 were identified in alfalfa roots under As stress. These genes have putative functions in abiotic stress homeostasis, antioxidant activity, and plant defense. These identified genes would be useful to increase As tolerance in alfalfa plants.

• Journal of Microbiology and Biotechnology
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• 제21권10호
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• pp.1064-1068
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• 2011

The osmotolerant yeast, Candida magnoliae, which was isolated from honeycomb, produces erythritol from sugars such as fructose, glucose, and sucrose. Erythrose reductase in C. magnoliae (CmER) reduces erythrose to erythritol with concomitant oxidation of NAD(P)H. Sequence analysis of the 5'-flanking region of the CmER gene indicated that one putative stress response element (STRE, 5'-AGGGG-3'), found in Saccharomyces cerevisiae, exists 72 nucleotides upstream of the translation initiation codon. An enzyme activity assay and semiquantitative reverse transcription polymerase chain reaction revealed that the expression of CmER is upregulated under osmotic and salt stress conditions caused by a high concentration of sugar, KCl, and NaCl. However, CmER was not affected by osmotic and oxidative stress induced by sorbitol and $H_2O_2$, respectively. The basal transcript level of CmER in the presence of sucrose was higher than that in cells treated with fructose and glucose, indicating that the response of CmER to sugar stress is different from that of GRE3 in S. cerevisiae, which expresses aldose reductase in a sugarindependent manner. It was concluded that regulation of CmER differs from that of other aldose reductases in S. cerevisiae.

• Asian Pacific Journal of Cancer Prevention
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• 제14권4호
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• pp.2349-2354
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• 2013

NAD(P)H: quinone oxidoreductase 1 (NQO1) C609T gene polymorphisms have been reported to influence the risk for digestive tract cancer (DTC) in many studies; however, the results remain controversial and ambiguous. We therefore carried out a meta-analysis of published case-control studies to derive a more precise estimation of any associations. Electronic searches were conducted on links between this variant and DTC in several databases through April 2012. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to estimate the strength of associations in fixed or random effect models. Heterogeneity and publication bias were also assessed. A total of 21 case-control studies were identified, including 6,198 cases and 7,583 controls. Overall, there was a statistically significant association between the NQO1 C609T polymorphism and DTC risk (TT vs. CC: OR=1.224, 95%CI=1.055-1.421; TT/CT vs. CC: OR=1.195, 95%CI=1.073-1.330; TT vs. CT/CC: OR=1.183, 95%CI=1.029-1.359; T vs. C: OR=1.180, 95%CI=1.080-1.290). When stratified for tumor location, the results based on all studies showed the variant allele 609T might have a significantly increased risk of upper digest tract cancer (UGIC), but not colorectal cancer. In the subgroup analysis by ethnicity, we observed a significantly risk for DTC in Caucasians. For esophageal and gastric cancer, a significantly risk was found in both populations, and for colorectal, a weak risk was observed in Caucasians, but not Asians. This meta-analysis suggested that the NQO1 C609T polymorphism may increase the risk of DTC, especially in the upper gastric tract.

• 생명과학회지
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• 제26권5호
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• pp.531-536
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• 2016

본 연구는 최근 연구자 등이 보고한 NQO1 knockout (결핍) 생쥐의 점막기능 감소 및 장염유발 현상을 인간 대장상피세포에서 재확인하는 것이다. 이를 위해, 사람 대장상피세포주인 HT29 세포에 NQO1 억제제인 dicumarol을 처치한 다음 밀착연접 조절인자의 변화를 평가하였다. HT29 세포에 10 μM dicumarol을 처치하여 NQO1을 억제하면 인간 대장상피세포의 밀착연접이 유의하게 줄고 구성인자들(ZO1, occludin)의 단백질 양도 감소함을 확인하였다. 생쥐 대장 내강에 dicumarol (10 μM)을 직접 처치한 결과 점막 투과율이 현저하게 증가함도 확인하였다(장벽기능 감소). 이는 인간 대장상피세포의 밀착연접 형성과정이 NQO1에 의존적임을 보여준다. 그러나 dicumarol 처치는 ZO1과 occludin의 전사량을 억제하지 않았다. NOQ1 결핍 생쥐에서 ZO1과 occludin의 전사량이 크게 감소한다는 이전 보고를 감안하면, NQO1에 의한 밀착연접 단백질의 양적 조절 과정이 전사를 포함하는 다양한 경로와 연관되어 있음을 시사한다. 즉, NQO1에 의한 ZO1과 occludin 조절 과정에 프로테오좀 의존-단백질 변성과 같은 단백질 파괴 경로가 이용될 수 있다고 사료된다.