• Journal of Plant Biology
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• 제34권1호
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• pp.53-57
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• 1991

대두의 자엽을 제거한 유식물에서 polyamine과 methylglyoxal bis(guanylhydrazone)(MGBG)가 diamine oxidase의 활성에 미치는 영향을 조사하여 다음과 같은 결과를 얻었다. $10^{-2}\;M$의 putrescine, spermidine과 spermine을 처리하였을 때에는 diamine oxidase의 활성이 약 80% 억제되었으나, $10^{-6}\;M$의 putrescine을 처리하였을 때에는 효소의 활성이 증가되었다. 이는 기질 특이성이 큰 putrescine에 의해 diamine oxidase가 유도될 수 있다고 사료된다. MGBG의 농도가 증가함에 따라 putrescine 함량이 증가되었다. In vitro에서 diamine oxidase의 활성은 $10^{-3}\;M$의 MGBG에서 약 40% 억제되었다. In vivo에서 diamine oxidase의 활성은 저농도의 MGBG에서 증가되었는데, 이는 MGBG가 putrescine으로부터 spermidine 형성을 억제하여 이로 인해 축적된 putrescine이 putrescine으로부터 spermidine 형성을 억제하여 이로 인해 축적된 putrescine이 diamine oxidase를 유도하는 것으로 사료된다. 반면, 고농도의 MGBG에서는 diamine oxidase의 활성이 감소되었다. 따라서 고농도의 MGBG에 의해 putrescine의 함량이 증가하는 것은 MGBG가 putrescine을 분해하는 diamine oxidase의 활성을 억제하는데 기인하는 것으로 사료된다.

• 한국식품영양과학회지
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• 제20권3호
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• pp.209-213
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• 1991

Methanethiol을 흰쥐에 투여시 혈청중 alanine aminotransferase 활성이 대조군 보다 약 3배의 유의한 증가를 보였으며, 이때 간 및 혈청중 xanthine oxidase 활성은 감소되는 경향을 보였다. 또한 간효소맥과 methanethiol의 혼액을 $37^{\circ}C$에서 preincuabation 시킨후 in vitro에서 xanthine oxidase활성을 측정 하였을때 본 효소의 활성이 억제됨과 동시에 기절인 xanthine의 량을 변화 시켜가면서 관찰한 kinetic 실험에서도 대조 시험에 비하여 Km치가 높게 나타났다.

• 생명과학회지
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• 제16권5호
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• pp.866-869
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• 2006

감자 polyphenol oxidase에 대한 솔잎 추출물의 저해효과가 조사 되었다. 솔잎 추출물은 anti-browning agents인 potassium sorbate나 citric acid보다도 더 강한 저해효과 를 나타냈으며 pH 7.0-8.0 사이에서 가장 강력한 저해효과가 있음을 알 수 있었다. 또한 반응시간이 증가 할수록 감자 polyphenol oxidase 활성은 현저하게 저해 되었으며 솔잎 추출물은 감자 polyphenol oxidase에 대해 비경쟁적인 저해를 하는 것으로 나타났다. 솔잎 추출물은 $100^{\circ}C$ 에서 10분간 열처리시에도 안정 하였으며 pH 2.0, 3.0, 4.0에서 3시간 처리시에도 여전히 감자 polyphenol oxidase 에 대한 저해효과를 보유하고 있어서 산과, 열에 비교적 안정한 물질임을 알 수 있었다.

• Journal of Microbiology
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• 제40권2호
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• pp.125-128
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• 2002

The aerobic respiratory chain of Vibrio alginolyticus possesses two different kinds of NADH oxidase systems, i.e., an $Na^{+}$-dependent NADH oxidase system and an $Na^{+}$-independent NADH oxidase system. When deamino-NADH, which is the only substrate for the $Na^{+}$-dependent NADH oxidase system, was used as a substrate, the maximum activities of $N^{+}$-dependent NADH: quinone oxidoreductase and $Na^{+}$-dependent NADH oxidase were obtained at about 0.06 M and 0.2 M NaCl, respectively. When NADH, which is a substrate for both $Na^{+}$-dependent and $Na^{+}$-independent NADH oxidase systems was used as a substrate, the NADH oxidase activity had a pH optimum at about 8.0. In cGntrastl when deamino-NADH was used as a substrate, the NADH oxidase activity had a pH optimum at about 9.0. On the other handle inside-out membrane vesicles prepared from the wild-type bacterium generated only a very small $\Delta$pH by the NADH oxidase system, whereas inside-out membrane vesicles prepared from Napl, which is a mutant defective in the $Na^{+}$ pump, generated $\Delta$pH to a considerable extent by the NADH oxidase system. On the basis of the results\ulcorner it was concluded that the respiratory chain-linked components of V. atginotyticus affect each other.

• 한국식품영양과학회지
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• 제22권6호
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• pp.797-802
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• 1993

The properties of the alcohol-oxidase from yeasts assimilating of methanol(Hansenula polymorpha CBS 4732, Pichia pastoris CBS 2612 and Candida boidinii CBS 8106) as free(cellules, purified enzymes) and immobilized forms(immobilized cellules, immobilized enzymes) were investigated. Immobilization enhanced the activity and stability of alcohol-oxidase to a certain degree. The optimum temperature of the immobilized alcohol-oxidase was lower than those of the free forms. The pH / activi쇼 profiles of alcohol-oxidase did not change by immobilization, but changed by the microorganisms. When the immobilized cellules were stocked at 4$^{\circ}C$ in 10mM potassium phosphate buffer(pH 7.5 or 8.0), alcohol-oxidase was more stable than those were stocked in potassium phosphate buffer containing 0.65M sucrose. The immobilization modifies the conditions of oxidation on the various substrates. alcohol-oxidase in immobilized forms showed some with higher Km value for methanol than that in free ones.

• 약학회지
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• 제39권5호
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• pp.521-527
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• 1995

This study was done to determine the effect of lead acetate on the activities of the hepatic cytosofic xanthine oxidase and aldehyde oxidase which were well known as oxygen free radical generating enzyme in vitro. Lead ion accelerated the formation of lipid peroxide and the increment of xanthine oxidase(type O) activity and the type conversion ratio from xanthine dehydrogenase to xanthine oxidase dose-dependently. But xanthine dehydrogenase(type D) activity was decreased. Aldehyde oxidase activity was not changed by lead ion. These data suggested that lead-induced cellular to)dcity may be concerned partially with xanthine oxidase mediated lipid peroxidation.

• 한국식품영양과학회지
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• 제22권4호
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• pp.418-422
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• 1993

기능성 식품과 생약재료의 이용을 위한 연구의 일환으로 한국산 녹차로부터 탄닌을 분리하여 xanthine oxidase 저해효과를 측정하였다. 녹차의 acetone 추출물에서 xanthine oxidase 저해효과가 있음이 확인되었고 정제된 탄닌의 효소 저해효과를 검토한 결과 xanthine oxidase 저해의 경우 galloyl tannin류가 nonga-lloyl tannin류보다 활성이 더 우수하였고 구조적 이성체에서도 (+)-catechin류 보다 (-)-epicatechin류가 효소저해 효과가 더 좋았으며, 각 물질간 상승 효과가 인정되었다. 녹차에서의 탄닌류는 xanthine oxidase에 대해 비경쟁적 저해를 하는 것을 알 수 있었다.

• BMB Reports
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• 제29권4호
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• pp.300-307
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• 1996

ATP and ADP are potential regulators of mitochondtial respiration and at physiological concentrations they affect the rate of electron transfer between cytochrome c and cytochrome c oxidase. The electron transfer, however, depends on the electrostatic interaction between the two proteins. In order to exclude any nonspecific ionic effects by these polyvalent nucleotides, we used 2'-O-(2,4,6)trinitro(TNP)-derivatives of ATP and ADP which have three orders of magnitude higher affinity for cytochrome c oxidase. A simple titration of the fluorescence intensity of TNP by cytochrome c oxidase showed a binding stoichiometry of 2:1 cytochrome c:cytochrome c oxidase. Higher ionic strength was required for TNP-ATP than for TNP-ADP to be dissociated from cytochrome c oxidase, indicating that the negative charges on the phosphate group are at least partially responsible for the binding. In both spectrophotometric and polarographic assays, addition of ATP (and ADP to a less extent) showed an enhanced cytochrome c oxidase activity. Both electron paramagnetic resonance and fluorescence spectra indicate that there is no Significant change in the cytochrome c-cytochrome c oxidase interaction. Instead, reduction levels of the cytochromes at steadystate suggest that the increased activity of nucleotide-bound cytochrome c oxidase is due to faster electron transfer from cytochrome ${\alpha}$ to cytochrome ${\alpha}_3$, which is known to be the fate limiting step in the oxygen reduction by cytochrome c oxidase.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 C
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• pp.984-986
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• 1999

In the case of immobilizing of glucose oxidase in organic polymer using electrosynthesis, the glucose oxidase obstructs charge transfer and mass transport during the film growth. This may lead to short chained polymer and make charge-coupling weak between the glucose oxidase and the backbone of the polymer. That is mainly due to insulating property and net chain of the glucose oxidase. Such being the case, it is useless to increase in amount of glucose oxidase more than reasonable in the synthetic solution. We establish by means of qualitative analysis that amount of immobilized glucose oxidase can be improved by adding a hole ethyl alcohol in the synthetic solution. As ethyl alcohol was added by 0.1mol $dm^{-3}$ in the synthetic solution, the faradic impedance of resultant electrode was increased about five times as much as the case of ethyl alcohol free in the solution, and mass transport was limited more than over. That is due to insulating property and net chain of the glucose oxidase. Moreover, in ultraviolet spectra of the synthetic solution, the adsorption peak at 285nm corresponding to glucose oxidase was decreased. It suggests increase in amount of immobilized glucose oxidase.

• Journal of Microbiology
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• 제44권3호
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• pp.284-292
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• 2006

The cbb3 cytochrome c oxidase has the dual function as a terminal oxidase and oxygen sensor in the photosynthetic bacterium, Rhodobacter sphaeroides. The cbb3 oxidase forms a signal transduction pathway together with the PrrBA two-component system that controls photosynthesis gene expression in response to changes in oxygen tension in the environment. Under aerobic conditions the cbb3 oxidase generates an inhibitory signal, which shifts the equilibrium of PrrB kinase/phosphatase activities towards the phosphatase mode. Photosynthesis genes are thereby turned off under aerobic conditions. The catalytic subunit (CcoN) of the R. sphaeroides cbb3 oxidase contains five histidine residues (H2l4, B233, H303, H320, and H444) that are conserved in all CcoN subunits of the cbb3 oxidase, but not in the catalytic subunits of other members of copper-heme superfamily oxidases. H214A mutation of CcoN affected neither catalytic activity nor sensory (signaling) function of the cbb3 oxidase, whereas H320A mutation led to almost complete loss of both catalytic activity and sensory function of the cbb3 oxidase. H233V and H444A mutations brought about the partial loss of catalytic activity and sensory function of the cbb3 oxidase. Interestingly, the H303A mutant form of the cbb3 oxidase retains the catalytic function as a cytochrome c oxidase as compared to the wild-type oxidase, while it is defective in signaling function as an oxygen sensor. H303 appears to be implicated in either signal sensing or generation of the inhibitory signal to the PrrBA two-component system.