• 한국식품과학회지
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• 제24권6호
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• pp.558-562
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• 1992

Xanthine oxidase는 퓨린 대사에 관여하여 xanthine 혹은 hypoxanthine을 산화하여 요산을 생성하게 하는 효소이다. 이상 퓨린 대사로 인해 형성된 요산은 관절에 축적되어 통풍을 동반하는 통증을 유발한다. 본 연구는 천연물로부터 통풍치료제의 개발을 목적으로 우롱차로 부터 6종의 flavan-3-ol 화합물을 분리하였고 기기분석에 의해 화학구조를 밝혔다. 각 화합물은 (-)-epicatechin, (-)-epicatechin-3-O-gallate, procyanidan B-1, B-3, procyanidin B-3-3'-O-rhamnose procyanidin B-1-3-O-gallate 였다. Xanthine oxidase 저해 영향을 관찰한 결과 gallte가 결함된 flavan-3-ol 화합물이 저해활성이 강하였고 procyanidin B-1-3-O-gallate는 $50\;{\mu}M$에 완전한 저해효과를 나타내었고 xanthine oxidase에 경쟁적으로 저해한다는 것이 밝혀졌다.

• Applied Biological Chemistry
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• 제34권1호
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• pp.49-53
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• 1991

참나물로부터 추출한 polyphenol oxidase의 부분정제를 $(NH_4)_2SO_4$, 처리 및 Sephadex G-150 column chromatography에 의해 분리하였다. Polyphenoloxidase의 최적 pH와 최적온도는 7.5와$30^{\circ}C$였으며, pH 6.5에서 $70^{\circ}C$에서 30분간 처리시와 $80^{\circ}C$에서 5분간 처리시 완전 실활하였다. Polyphenol oxidase는 ascorbic acid, glutathione, potassium cyanide(0.1mM)에 의해 불활성화되었으며 L-cysteine, potassium cyanide, ascorbic acid, glutathione(0.5, 1mM)에 의해서는 완전 실활되었다. Catechol과 3,4-dihydroxytoluene의 기질은 높은 특이성을 나타낸 반면 pyrogallol, dopamine, DL-dopa의 기질은 강하게 활성을 억제하였다. Polyphenol oxidase의 $K_m$ 값은 86.5mM이었다.

• 한국미생물·생명공학회지
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• 제20권4호
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• pp.395-400
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• 1992

토양으로부터 cholesterol oxidase 생산성이 있는 균주를 분리하고, 이들 분리된 균주들로 부터 여러 단계의 균주 선발 실험을 통하여 cholesterol oxidase 생산성이 가장 우수한 미생물을 선별하여 HSL613이 라고 명명하였다. 이 HSL613은 $37^{\circ}C$에서 보다 $30^{\circ}C$에서 배양했을 때 더 높은 효소생산성을 나타내었고 배양시간이 경과함에 따라 pH가 높아지면서 효소생산이 증가하여, 144시간 배양하였을 때 pH는 8.5로 높아졌고 효소생산량도 가장 높았다. 균체량은 120 시간 배양하였을 때 가장 많았다. 본 실험에서 HSL613의 효소생산조건을 검토한 결과 최적 배지조성은 2.0% glucose, 2.0% yeast extract, 0.2% $K_2HP0_4$, 0.1% NaCl. 0.005% $CaCl_22H_2O, 0.001% $FeSO_47H_20$ 로 판명되었으며, $30^{\circ}C$에서 144시간 (6일때) 배양하였을 때 효소생성이 가장 많았고 (10.3U/ml), 종균의 접종량은 1.0%(v/v)일때가 가장 효소생성이 잘 되었다.

• BMB Reports
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• 제31권3호
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• pp.227-232
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• 1998

The leukocyte NADPH oxidase of neutrophils is a membrane-bound enzyme that catalyzes the production of $O_2^-$ from oxygen using NADPH as an electron donor. Dormant in resting neutrophils, the enzyme acquires catalytic activity when the cells are exposed to appropriate stimuli. During activation, the cytosolic oxidase components $p47^{phox}$ and $p67^{phox}$ migrate to the plasma membrane, where they associate with cytochrome $b_{558}$, a membrane-bound flavohemoprotein, to assemble the active oxidase. The oxidase can be activated in a cell-free system; the activating agent usually employed is an anionic amphiphile such as sodium dodecyl sulfate (SDS). Because $p47^{phox}$ can translocate by itself during activation, the conformational change in $p47^{phox}$ may be responsible for the activation of NADPH oxidase. We show here that the treatment of $p47^{phox}$ with SDS leads to an increase in the reactivity of the sutbydryl group of cysteines toward N-ethylmaleimide, indicating that the conformational change occurs when $p47^{phox}$ is exposed to SDS. We propose that this change in conformation results in the appearance of a binding site through which $p47^{phox}$ interacts with cytochrome $b_{558}$during the activation process.

• BMB Reports
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• 제34권1호
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• pp.21-27
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• 2001

The structural stability of brain pyrydoxine-5'-phosphate (PNP) oxidase and the catalytic properties of the monomeric species were investigated. The unfolding of brain pyridoxine-5'-phosphate (PNP) oxidase by guanidine hydrochloride (GuHCl) was monitored by means of fluorescence and circular dichroism spectroscopy Reversible dissociation of the dimeric enzyme into subunits was attained by the addition of 2 M GuHCl. The perturbation of the secondary structure under the denaturation condition resulted in the release of the cofactor FMN. Separation of the processes of refolding and reassociation of the monomeric species was achieved by the immobilization method. Dimeric PNP oxidase was immobilized by the covalent attachment to Affi-gel 15 without any significant lass of its catalytic activity. Matrix-bound monomeric species were obtained from the reversible refolding processes. The matrix bound-monomer was found to be catalytically active, possessing only a slightly decreased specific activity when compared to the refolded dimeric enzyme. In addition, limited chymotrypsin digestion of the oxidase yields two fragments of 12 and 161 kDa with a concomitant increase of catalytic activity The catalytically active fragment was isolated by ion exchange chromatography and analyzed for association of two subunits using the FPLC gel filtration analysis. The retention time indicated that the catalytic fragment of 16 kDa behaves as a compact monomer. Taken together, these results are consistent with the hypothesis that the native quaternary structure of PNP oxidase is not a prerequisite for catalytic function, but it could play a role in the regulation.

• 대한약리학회지
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• 제18권2호
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• pp.27-32
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• 1982

만성 정신분렬병 환자에서 성(性)에 따른 혈소판 MAO 활성도의 변화양상을 분석하고 이에 관련하여 혈장 Testosterone 및 Estradiol농도의 변화를 검토하고자, 135명의 정상대조군과 78명의 만성 정신분렬병 환자를 대상으로 하여 혈소판 MAO활성도와 혈장 Testosterone 및 Estradiol농도를 측정한 결과는 다음과 같다. 1) 만성 정신분렬병 환자에서 혈소판 MAO활성도는 남녀 모두 그 정상대조군에 비하여 낮은 사람이 더 많았다. 2) 혈소판 MAO활성도의 남녀간의 차이는 정상대조군에서는 없었지만 만성 정신분렬병 환자가 여자 환자에 비해 혈소판 MAO활성도가 낮은 사람이 더 많았다. 3) 남자 정신분렬병 환자에서는 혈장 Estradiol농도만 정상대조군에 비하여 저하되어 있었고, 여자 정신분렬병 환자에서는 혈장 Testosterone농도만 정상대조군에 비하여 저하되어 있었다.

• 약학회지
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• 제56권2호
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• pp.80-85
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• 2012

Previously, we have reported that arachidonic acid (AA) appears to be involved in the induction of apoptosis in HepG2 human hepatoblastoma cells. In this study we investigated the possible role of the NADPH oxidase, a membranebound enzyme generating reactive oxygen species (ROS), in the mechanism of AA-induced apoptosis in HepG2 cells. Apoptotic cell death induced by AA was significantly suppressed by various inhibitors of the NADPH oxidase, diphenylene iodonium (DPI), apocynin (Apo) and neopterine (NP). In addition, these inhibitors of the NADPH oxidase completely blunted the AA-induced ROS elevation. Next, we investigated the implication of metabolic pathway of AA in these AA actions. Both apoptosis and ROS production induced by AA were not significantly altered by treatment with indomethacin (Indo) or nordihydroguaiaretic acid (NDGA), selective inhibitors of cyclooxygenase (COX) and lipoxygenase (LOX), respectively, suggesting that AA metabolites produced by COX or LOX may not have an essential role in the AA-induced apoptosis and ROS generation. Collectively, these results suggest that the NADPH oxidase may be a key player in the mechanism of AA-induced apoptosis in HepG2 cells. These results further suggest that NADPH oxidase may be a good target for the management of human hepatomas.

• Advances in Traditional Medicine
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• 제1권1호
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• pp.64-70
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• 2000

Effects of Rhizoma gastrodiae on glucose oxidase-induced neurotoxicity was investigated in cultured newborn mouse spinal dorsal root ganglion(DRG) neurons that were treated in the media with or without glucose oxidase. In addition, the protective effect of Rhizoma gastrodiae extract against glucose oxidase-induced neurotoxicity was examined. Cytotoxic values were expressed as a percentage of number of living cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. In this paper, exposure of neurons to glucose oxidase resulted in a significant call death in a dose- and time-dependent manners in DRG neuron cultures. The decrease in cell viability induced by the glucose oxidase was blocked by Rhizoma gastrodiae extract. These results indicate that the neuroprotective effect of Rhizoma gastrodiae extract against glucose oxidase-induced neurotoxicity may result from a prevention or attenuation of oxidative damage induced by glucose oxidase.

• Journal of Plant Biology
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• 제38권3호
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• pp.235-242
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• 1995

Effects of methyl jasmonate (MeJA) on ethylene production in tomato(Lycopersicon esculentum Mill.) hypocotyl segments and fruits were studied. Ethylene production in tomato hypocotyl segments was inhibited by the increasing concentratons of MeJA, and 450 $\mu$M of MeJA showed 50% inhibitory effect. Time course data indicate that this inhibitory effect of MeJA appeared after 3 h of incubation period and continued until 24 h. Inhibition of ethylene producton by MeJA was due to the decrease in 1-aminocyclopropane-1-carboxylic acid(ACC) synthase activity. However, MeJA treatment had no effect on ACC oxidase activity and the accumulaton of ACC oxidase mRNAs. MeJA also inhibited auxin-induced ethylene production by decreasing in ACC synthase activity. In contrast, MeJA stimulated ethylene production in tomato fruits. When 30 $\mu$L/mL MeJA was treated in a gaseous state, ethylene production doubled and this stimulating effect continued until 4 days. To investigate the mechanisms of MeJA on ethylene production, ACC synthase and ACC oxidase activities were examined after MeJA treatment. MeJA increased the activities of both ACC synthase and ACC oxidase, and induced ACC oxidase mRNA accumulation. These data suggest that MeJA plays distinct roles in the ethylene production in different tomato tissues. It is possible that MeJA affects differently the mechanisms of signal transuction leading to the ethylene biosynthesis.

• 분석과학
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• 제8권4호
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• pp.591-596
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• 1995

Enzyme multilayers composed of avidin and biotin-labeled enzymes were prepared on the surface of electrode, through a strong affinity between avidin and biotin (binding constant: ca $10^{15} M^{-1}$). The enzyme multilayers were useful for the improvement of the performance characteristies of enzyme sensors. The output current of the enzyme sensors depended linearly on the number of enzyme layers deposited. Thus, lactate oxidase (LOx) and alcohol oxidase (AlOx) were deposited after being modified with biotin for constructing enzyme sensors sensitive to L-lactate and ethanol respectively. It was also possible to deposit two different kinds of enzymes successively in a single multilayer. The glucose oxidase (GOx) and ascorbate oxidase (AsOx) were built into a multilayer structure on a Platinum electrode. The GOx, AsOx multilayer-modified electrode was useful for the elimination of ascorbic acid interference of the glucose sensor.