• 한국미생물·생명공학회지
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• 제9권4호
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• pp.179-183
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• 1981

진균류의 세포벽제거 및 이에 따른 protoplast생성 등에 많이 이용되어지고 있는 chitinase를 Streptomyces sp. 115-5 균주로부터 생산하여 순수 정제한 다음, 이 chitinase의 작용을 저해하는 포도당의 저해양상을 조사하였다. 포도당 외에 D-glucuronic acid, D-sorbitol및 D-xylose등도 chitinase의 활성을 저해하였다. 그런고로, 포도당 분자에 의한chitinase의 활성 저해 효과에는 위의 분자들의 공통부분인 2번, 3번 및 4번 탄소의 hydroxyl group들의 구조위치가 중요한 영향을 가진다는 것을 알 수 있다. 그리고 포도당에 의한 chitinase의 저해양상은 competitive inhibition 과 non-competitive inhibition 과의 혼합 저해형으로 나타났다.

• Journal of Applied Biological Chemistry
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• 제60권2호
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• pp.173-178
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• 2017

본 연구는 요소비료를 처리할 때 가수분해가 일어나 암모니아로 휘산되어 손실되는 것을 억제하기 위한 목적으로 목초액이 요소분해에 미치는 영향을 규명하고자 하였다. 기존에 수많은 요소분해 합성억제제들이 개발 또는 탐색되어 왔으나, 토양 또는 환경 별로 효과가 일정치 않고 합성물질의 경우 환경에 미치는 영향을 고려해야 한다는 점 등 때문에 그 사용이 제한되고 있는 실정이다. 본 연구에서는 친환경 농업자재인 목초액이 토양 중 요소분해에 미치는 영향을 요소분해효소(urease)활성 억제효과를 통해 평가하였다. 목초액은 식물 urease와 미생물 urease 활성저해 효과뿐만 아니라 다양한 urease complex가 존재하는 토양 urease에도 저해효과를 보였다. 이러한 요소분해효소의 저해는 jack bean urease 반응속도를 측정한 결과 non-competitive inhibition으로 판단된다. 또한 목초액을 요소와 함께 토양에 처리하였을 경우 토양 내 요소분해작용을 억제하였다. 이를 통해 목초액을 요소 비료와 같이 처리할 경우 식물에 공급되는 질소의 효율을 증진시킴과 동시에 토양에 공급되는 질소비료의 총량을 절감하여 친환경 농업에 도움이 될 것으로 판단된다.

• Biomolecules & Therapeutics
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• 제3권1호
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• pp.34-37
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• 1995

Non-steroidal anti-inflammatory drugs (NSAIDs) have been known as inhibitors of the folate-requiring enzymes. In the present work, we have expanded on these observations and have investigated the inhibitory effects of NSAIDs on Lactobacillus casei thymidylate synthase expressed in E. coli. NSAIDs including sulphasalizine, salicylic acid, indomethacin and mefenamic acid were found to be competitive inhibitors with respect to folate of Lactobacillus casei thymidylate synthase. In contrast, aspirin and the antipyretic-analgesic drugs acetaminophen and antipyrine were weak inhibitors of the enzyme. Structure-activity correlation suggests that an aromatic ring with a side chain containing a carboxylic acid is a requirement for competitive inhibition of the thymidylate synthase. The results are consistent with the hypothesis that the antifolate activity of NSAIDs, and hence cytostatic consequences, are important factors in producing anti-inflammatory activity and aspirin exerts its anti-inflammatory effects after its conversion into salicylic acid, which possesses greater antifolate activity than its parent compound.

• Archives of Pharmacal Research
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• 제9권2호
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• pp.81-86
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• 1986

The effect of imperatorin on hepatic microsomal mixed function oxidases (MF0) was investigated. On acute treatment, imperatorin (30 mg/kg, i.p) caused a significant reduction in activities of hepatic aminopyrine N-demethylase, hexobarbital hydroxylase and aniline hydroxylase as well as cytochrome p0450 content in rats and mice. Kinetic studies on rat liver enzymes revealed that imperatorin appeared to be a competitive inhibitor of aminopyrine N-demethylase (Ki,0.007 mM), whereas a non-competitive inhibitor of hexobarbital hydroxylase (Ki, 0.0148 mM). Imperatorin also inhibited non-competitively aniline metabolism (Ki 0.2 mM). Imperatorin binds to phenobarbital-induced cytochrome p-450 to give a typical type 1 binding sepctrum (max. 388nm, min 422 nm). Multiple administrations of imperatorin (30 mg/kg. i. p. daily for 7 days) to mice shortended markedly the duration of hexobarbital narcosis and increased activities of hepatic aminopyrine N-demethylase and hexobarbital hydroxylase and the level of cytochrome p-450 where as aniline hydroxylase activity was unaffected.

• BMB Reports
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• 제28권4호
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• pp.290-292
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• 1995

Existence of a binding site for choline esters with an acyl chain of various sizes was examined by comparing the inhibitory potency of the respective compound. In contrast to acetylcholine, which showed a pure competitive pattern of inhibition, choline esters with an acyl chain of a long size ($C{\geq}5$) expressed a mixed type of inhibition. Binding of choline esters containing a long chain ($C_7-C_{12}$) to the hydrophobic region in the active site is deduced from a linear relationship between the $K_{iE}$ value and the size of acyl moiety, and a good hydrophobicity relationship. In addition, the non-competitive component in the inhibition of acetylcholinesterase seems to be due to the interaction of choline esters with both the hydrophobic site and the trimethylammonium-binding site in the active center of the acetylated acetylcholinesterase.

• 생약학회지
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• 제37권4호
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• pp.320-323
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• 2006

The effects of evodiamine on monoamine oxidase (MAO) activity were investigated. MAO was purified from mouse brain and the $K_m\;and\;V_{max}$ values of MAO were $78.5{\pm}5.28{\mu}M$ and $0.68{\pm}0.07$ nmol/min/mg protein, respectively (n=4). Evodiamine at $30-120{\mu}M$ showed an inhibitory effect on MAO activity using a substrate kynuramine with an $IC_{50}$ value of $104.2{\mu}M$ (n=4). Evodiamine also exhibited a non-competitive inhibition on MAO. The $K_i$ value for evodiamine was $72.5{\pm}10.8{\mu}M$ (n=4). These results suggest that evodiamine partially contributes to the regulation of monoamine content.

• 한국미생물·생명공학회지
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• 제10권4호
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• pp.283-288
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• 1982

Streptomyces속 균이 생산하는 trypsin inhibitor의 trypsin에 대한 반응성을 조사해 본 결과 본 저해물질은 crystalline trypsin (20.000 unit, hog pancreas)에 대하여 1/8량에서 약 50%의 저해률을 나타내었으며 trypsin에 대한 저해양상은 mixed noncompetitive-competitive inhibition type이었으며 enzyme-inhibitor complex를 빨리 형성하는데 반응액중 isoleucine이 공존하면 활성이 증가되였으며 Ag$_{＋}$ Hg$_{＋＋}$등의 금속ion은 강하게 본 저해물질의 작용을 억제하였다. 저해률은 사용한 기질의 종류에 따라 차이가 나서 albumin을 사용하였을 때는 casein이나 hemoglobin을 사용하였을 때보다 저해률이 높았다. 그러고 혈액의 응고에 대해서도 저해작용을 나타내었다.

• 생약학회지
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• 제35권4호통권139호
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• pp.271-275
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• 2004

Distylium racemosum Sieb. Et Zucc contains some compounds inhibit -amylase activity in experimental conditions. The inhibitory test showed that 50% acetone extracts from the bark and leaves of the plant strongly inhibited salivary -amylase activity. Proanthocyanidin(PA) which has strong inhibitory activity was extracted from the leaves by chromatography on Sephadex LH-20. The inhibitory activities and the inhibition kinetics of the PA were studied against three kinds of enzymes: human salivary ${\alpha}-Amylase$ (SAA), pork pancreatin ${\alpha}-Amylase$ (PAA) and yeast ${\alpha}-Glucosidase$ (AG). Then the activities of PA against SAA, PAA and AG were compared with those of acarbose, a commercial agent. The inhibitory activities of PA were stronger than those of acarbose. Inhibition kinetics of the PA showed competitive inhibition for SAA and PAA, and non competitive inhibition for GA.

• 대한수의학회지
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• 제23권1호
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• pp.9-16
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• 1983

The effects of ethanol on Na-K-ATPase activity were investigated with cat kidney homogenate. The results were summarized as follows: 1. Na-K-ATPase activity was inhibited with dose-dependent manner by ethanol of higher concentration than 1%, and showed an estimated $I_{50}$ (the inhibitor concentration to cause 50% inhibition) of 7.5%. 2. Hydrolysis of ATP was linear with the incubation time in the absence and presence of 8% ethanol, whereas it was different with preincubation time in the presence of 15% ethanol. 3. Inhibition of Na-K-ATPase activity by ethanol was not affected by increased enzyme concentration, and showed the reversibility of the inhibitory pattern. 4. Kinetic studies of cationic-substrate activation of Na-K-ATPase showed that ethanol had both properties of classical competitive inhibition for $Mg^{{+}{+}}$ or $K^+ and non-competitive inhibition for ATP or $Na^+$. 5. Arrhenius plot yield two break point at $21^{\circ}$ and $30^{\circ}C$ in the absence of ethanol, whereas showing only one break point at $18^{\circ}C$ in the presence of 8% ethanol. These results suggested that ethanol inhibited Na-K-ATPase activity reversible through a disturbance of microenvironment of lipids associated with the enzyme.

• Biomolecules & Therapeutics
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• 제16권4호
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• pp.336-342
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• 2008

The resveratrol analogue piceatannol (3,5,3',4'-tetrahydroxy-trans-stilbene) is a polyphenol present in grapes and wine and reported to have anti-carcinogenic activities. To investigate the mechanism of anticarcinogenic activities of piceatannol, the effects on CYP 1 enzymes were determined in Escherichia coli membranes coexpressing recombinant human CYP1A1, CYP1A2 or CYP1B1 with human NADPH-P450 reductase. Piceatannol showed a strong inhibition of CYP1A1 and CYP1B1 in a concentration-dependent manner, and $IC_{50}$ of human CYP1A1 and CYP1B1 was 5.8 ${\mu}M$ and 16.6 ${\mu}M$, respectively. However, piceatannol did not inhibit CYP1A2 activity in the concentration of up to 100 ${\mu}M$. Piceatannol exhibited 3-fold selectivity for CYP1B1 over CYP1A1. The mode of inhibition of piceatannol was non-competitive for CYP1A1 and CYP1B1. The result that piceatannol did not inhibit CYP1B1-mediated $\alpha$-naphthoflavone ($\alpha$-NF) metabolism suggests piceatannol may act as a non-competitive inhibitor as well. In human prostate carcinoma PC-3 cells, piceatannol induces apoptosis and prevents Aktmediated signal pathway. Taken together, abilities of piceatannol to induce apoptotic cell death as well as CYP1 enzyme inhibition make this compound a useful tool for cancer chemoprevention.