• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.5
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• pp.488-493
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• 1991

The characteristics of endogenous and exogenous polygalacturonase(PG) produced from L. acidophilus were investigated as one of the serial studies on the fermentation of Chinese cabbage kimchi using L. acidophilus. Apparent molecular weigth of endogenous and exogenous PG were estimated to be 420,000 and 500,000 daltons by the method of gel filtration and Vmax of the enzymes 8.0 and $0.3{\mu}mol$ galacturonic acid/ml/30min, respectively and Km of the enzymes were 4.0mg/ml. The optimum temperature, pH and salt concentration of the both enzymes were the same and appeared to $30^{\circ}C$, 5.5 and 2~3%, respectively. The activities of the endogenous and exogenous PG all were severely decreased by increasing of temperature to $90^{\circ}C\;from\;60^{\circ}C$ and its remained activities at $60^{\circ}C\;and\;90^{\circ}C$ were 50%, 58%, and 19%, 5%, respectively.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.12
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• pp.7187-7191
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• 2013

Most of the exogenous and endogenous chemical compounds are metabolized by enzymes of xenobiotic processing pathways, including the phase I cytochrome p450 species. Carcinogens and their metabolites are generally detoxified by phase II enzymes like glutathione-S-transferases (GST). The balance of enzymes determines whether metabolic activation of pro-carcinogens or inactivation of carcinogens occurs. Under certain conditions, deregulated expression of xenobiotic enzymes may also convert endogenous substrates to metabolites that can facilitate DNA adduct formation and ultimately lead to cancer development. In this study, we aimed to test the association between deregulation of metabolizing genes and brain tumorigenesis. The expression profile of metabolizing genes CYP1A1 and GSTP1 was therefore studied in a cohort of 36 brain tumor patients and controls using Western blotting. In a second part of the study we analyzed protein expression of GSTs in the same study cohort by ELISA. CYP1A1 expression was found to be significantly high (p<0.001) in brain tumor as compared to the normal tissues, with ~4 fold (OR=4, 95%CI=0.43-37) increase in some cases. In contrast, the expression of GSTP1 was found to be significantly low in brain tumor tissues as compared to the controls (p<0.02). This down regulation was significantly higher (OR=0.05, 95%CI=0.006-0.51; p<0.007) in certain grades of lesions. Furthermore, GSTs levels were significantly down-regulated (p<0.014) in brain tumor patients compared to controls. Statistically significant decrease in GST levels was observed in the more advanced lesions (III-IV, p<0.005) as compared to the early tissue grades (I-II). Thus, altered expression of these xenobiotic metabolizing genes may be involved in brain tumor development in Pakistani population. Investigation of expression of these genes may provide information not only for the prediction of individual cancer risk but also for the prevention of cancer.

• IMMUNE NETWORK
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• v.3 no.4
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• pp.276-280
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• 2003

Background: Peroxidases (Prx) of the peroxiredoxin family reduce hydrogen peroxide and alkyl hydroperoxides to water and alcohol respectively. Hydrogen peroxide is implicated as an intracellular messenger in various cellular responses such as proliferation and differentiation. And Prx I activity is regulated by Cdc-2 mediated phosphorylation. This work was undertaken to investigate the proliferation role of peroxiredoxin III as a member of Prx family in Prx III overexpressed HeLa cell line. Methods: To provide further evidence of proliferation, we selected Prx III stably expressed HeLa Tet-off cell lines. Cell proliferation was examined by using proliferation reagent WST-1 in the presence or absence of doxycycline. Prx III, 2-cys Prx enzymes exist as homodimer. The activation of Prx III heterodimer with induced and endogenous Prx III was examined by immunoprecipitation. Results: Immunoprecipitation analysis of the induced and endogenous Prx III with anti-myc showed that the induced wild type (WT) and dominant negative (DN) Prx III from HeLa Prx III Tet-off stable cell heterodimerized with endogenous Prx III each other. And the expression level of induced Prx III was examined after addition of doxycycline. By 72 hr, the expression level of induced Prx III was diminished gradually and the half-life of the induced wild type Prx III was approximately 17 hr. The proliferation experiment demonstrated that the relative proliferation value of induced and endogenous WT Prx III stable cell has no changes but the DN Prx III induced HeLa Tet-off stable cells were lower than endogenous Prx III. Conclusion: In conclusion, the HeLa dominant negative Prx III Tet-off stable cells were decreased the proliferation.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.6
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• pp.749-758
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• 1997

Myocardial ischemia-reperfusion injury is known to be mediated by reactive oxygen species. The myocardial cell is equipped with endogenous antioxidant defensive system which can be adaptively stimulated by various oxidative stress. It is postulated that an increased oxygen partial pressure induced by hyperbaric oxygenation impose an oxidative stress on the cells, resulting alterations in the endogenous antioxidant system. In this study we investigated the effect of hyperbaric oxygenation on the activities of myocardial antioxidant enzymes and observed whether the hyperbaric oxygenation could protect the ischemia-reperfusion injury of heart. Rats or rabbits were pretreated with hyperbaric $oxygenation(2{\sim}3\;atm\;O_2/1{\sim}3\;hrs/1{\sim}10\;days)$. The changes in activities of major antioxidant enzymes(superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glucose-6-phasphate dehydrogenase), functional recovery and infarct size were observed in the experimentally induced ischemia-reperfused hearts. In the hearts isolated from rats pretreated with $2\;atm\;O_2/1{\sim}2\;hrs$ for 5 days, the functional recovery after reperfusion(20 min) following global ischemia(25 min) was significantly increased without any observable oxygen toxicity. Lactate dehydrogenase release was also significantly reduced in this hyperbaric oxygenated rat hearts. In in vivo regional ischemia(30 min) model of rabbit hearts, pretreatrment with $2\;atm\;O_2/1\;hr$ for 5 days significantly limited the infarct size. Among the myocardial antioxidant enzymes of rat hearts pretreated with the hyperbaric oxygenation, the activities of catalase, superoxide dismutase and glucose-6-phosphatase dehydrogenase were increased, while those of glutathione peroxidase and reductase were not changed. There were lethal cases in the groups of rats exposed to 3 atm $3\;atm\;O_2/2{\sim}3\;hrs$ for 5 days. A lipid-peroxidation product, rnnlondialdehyde was increased in brains and livers of the rats exposed to$2\;atm\;O_2/2{\sim}3\;hrs/5\;days\;and\;3\;atm\;O_2/1\;hr/5days$. The present results suggest that the pretreatment of hyperbaric oxygenation can protect the post-ischemic rererfused hearts in association with a stimulation of the activities of myocardial antioxidant defensive enzymes, and that the hyperbaric oxygenation of $2\;atm\;O_2/1\;hr$for 5 days would be a safe condition which does not produce any oxygen toxicity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.1
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• pp.54-59
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• 1992

The characteristics of endogenous and exogenous ${\beta}-galactosidase\;({\beta}-Galase)$ produced from L. acidophilus were investigated as one of the serial studies on the fermentation of Chinese cabbage kimchi using L. acidophilus. Apparent molecular weight of endogenous and exogenous of the ${\beta}-Galase$ were investigated to be 550,000 and 740,000 daltons by the method of gel filtration and Km values of the both enzymes were 1.67mg/ml, 1.33mg/ml and $V_{max}$ were $8.5\;{\mu}\;mol/mg/30min.$, $2.65\;{\mu}\;mol/ml/30min.$, respectively. The optimum pH of the enzymes were 7 and 8, respectively. The optimum temperatures and salt concentrations of the both enzyme were the same and appeared to $30^{\circ}C$and$4{\sim}5%$, respectively. The activities of the endogenous and exogenous ${\beta}-Galase$ were decreased by increasing of temperature from $60^{\circ}C$to$90^{\circ}C$ and the decreasing rate of the enzyme activities on the processing of the heating times showed high at first 2 minutes of heating.

• BMB Reports
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• v.44 no.8
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• pp.497-505
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• 2011

Reactive oxygen species (ROS), which include superoxide anions and peroxides, induce oxidative stress, contributing to the initiation and progression of cardiovascular diseases involving atherosclerosis. The endogenous and exogenous factors hypercholesterolemia, hyperglycemia, hypertension, and shear stress induce various enzyme systems such as nicotinamide adenine dinucleotide (phosphate) oxidase, xanthine oxidase, and lipoxygenase in vascular and immune cells, which generate ROS. Besides inducing oxidative stress, ROS mediate signaling pathways involved in monocyte adhesion and infiltration, platelet activation, and smooth muscle cell migration. A number of antioxidant enzymes (e.g., superoxide dismutases, catalase, glutathione peroxidases, and peroxiredoxins) regulate ROS in vascular and immune cells. Atherosclerosis results from a local imbalance between ROS production and these antioxidant enzymes. In this review, we will discuss 1) oxidative stress and atherosclerosis, 2) ROS-dependent atherogenic signaling in endothelial cells, macrophages, and vascular smooth muscle cells, 3) roles of peroxidases in atherosclerosis, and 4) antioxidant drugs and therapeutic perspectives.

• Toxicological Research
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• v.32 no.2
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• pp.89-93
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• 2016

Human cytochrome P450 enzymes (P450s, CYPs) are major oxidative catalysts that metabolize various xenobiotic and endogenous compounds. Many carcinogens induce cancer only after metabolic activation and P450 enzymes play an important role in this phenomenon. P450 1B1 mediates bioactivation of many procarcinogenic chemicals and carcinogenic estrogen. It catalyzes the oxidation reaction of polycyclic aromatic carbons, heterocyclic and aromatic amines, and the 4-hydroxylation reaction of $17{\beta}$-estradiol. Enhanced expression of P450 1B1 promotes cancer cell proliferation and metastasis. There are at least 25 polymorphic variants of P450 1B1 and some of these have been reported to be associated with eye diseases. In addition, P450 1B1 polymorphisms can greatly affect the metabolic activation of many procarcinogenic compounds. It is necessary to understand the relationship between metabolic activation of such substances and P450 1B1 polymorphisms in order to develop rational strategies for the prevention of its toxic effect on human health.

• Radiation Oncology Journal
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• v.33 no.2
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• pp.66-74
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• 2015

Trace elements play crucial role in the maintenance of genome stability in the cells. Many endogenous defense enzymes are containing trace elements such as superoxide dismutase and metalloproteins. These enzymes are contributing in the detoxification of reactive oxidative species (ROS) induced by ionizing radiation in the cells. Zinc, copper, manganese, and selenium are main trace elements that have protective roles against radiation-induced DNA damages. Trace elements in the free salt forms have protective effect against cell toxicity induced by oxidative stress, metal-complex are more active in the attenuation of ROS particularly through superoxide dismutase mimetic activity. Manganese-complexes in protection of normal cell against radiation without any protective effect on cancer cells are more interesting compounds in this topic. The aim of this paper to review the role of trace elements in protection cells against genotoxicity and side effects induced by ionizing radiation.

• The Journal of Korean Medicine
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• v.18 no.2
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• pp.355-365
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• 1997

This study was undertaken to examine the effect of Cheongahwan(CAH), being known to reinforce Kidney-yang, on the activities of endogenous antioxidant enzymes and the production of oxygen free radicals in the kidney tissues. Alterations in enzyme activities were observed after in vivo treatment in rats. CAH caused a significant increase in the activities of superoxide dismutase (SOD), glutathione peroxidase and glutathione S-transferase. But catalase activity was not significantly altered by CAH. Treatment in vitro of CAH decreased the production of oxygen free radicals in a dose-dependent fashion. These results suggest that CAH stimulate the activities of antioxidant enzymes and inhibit directly the production of oxygen free radicals. These effects of CAH may contribute to prevent the oxygen free radical-induced impairment of cell function.

• YAKHAK HOEJI
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• v.37 no.6
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• pp.571-576
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• 1993

The substrate specificity of the purified rabbit plasma alkaline phosphatase (ALPase) was determined towards a extended range of potential substrates including relatively simple phosphate derivatives as p-NPP and indolyl phosphate, and several synthetic peptides and phosphoproteins. These results further estabilish the broad substrate specificity of these circulating enzymes. Interestingly, the plasma ALPase preferentially dephosphorylates Thr over Ser residues, as demonstrated with a series of synthetic peptides. The latter result is in contradiction to the behaviour of the tissue ALPase, which is thought to the ultimate source of plasma ALPase, and open therefore new perspectives with respective to the origin and "solubilisation" processes of these enzymes. Dephsphrylation of protein substrates by endogenous and isolated plasma ALPases indicates that ALPase probably displays protein phosphatase activity in vivo.