• BMB Reports
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• 제30권5호
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• pp.326-331
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• 1997

To construct a competitive ELISA standard curve for the detection of glucose-6-phosphate debydrogenase (G6PD), we used highly purified native G6PD (nG6PD) as both immobilized and soluble antigens and anti-G6PD serum raised against nG6PD as antibody. The polystyrene cuvettes coated with nG6PD were challenged with a mixture of a limiting amount of anti-G6PD serum and various doses of nG6PD as competitors followed by incubation with alkaline phosphatase-anti-IgG conjugate. The competitive ELISA did not exhibit the typical sigmoidal dose-response curve characteristic of competition immunoassays under the optimal concentrations of antigen and antibody. The soluble nG6PD used as competitor failed to effectively inhibit the binding of antibodies to the immobilized nG6PD. The addition of NADP, a cofactor of G6PD enzyme, to coating buffer used for immobilizing nG6PD to the cuvettes and PBS-Tween-BSA buffer for diluting competitors did not improve the inhibition of antibody binding to immobilized nG6PD by soluble n/G6PD. The addition of BSA to coating buffer did not increase inhibition, either. Surprisingly, when partially active G6PD (paG6PD), obtained by repeated freeze-thawing, was used as competitor, the antibody binding to either immobilized nG6PD or immobilized paG6PD was inhibited 49-58%. We conclude that an effective competitive ELISA system with nG6PD enzyme and anti-G6PD serum for the detection of G6PD may not be established due to the poor inhibition of antibody binding to immobilized nG6PD by soluble nG6PD under the present assay conditions and that the inhibition may be improved by using an inactivated enzyme as competitor regardless of the type of immobilized antigen used. These results imply that the immobilized nG6PD may undergo denaturation upon binding to the polystyrene cuvettes and that our anti-G6PD serum may recognize denatured enzyme better than active enzyme.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 추계학술발표회
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• pp.117-121
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• 2002

A numerical model that describes the reductive dechlorination of tetrachloroethene(PCE) to ethene via cis-dichloroethene(CDCE) was developed. The model included two separated dehalogenator groups : one for PCE transformation to cDCE via TCE and the other for cDCE dehalogenation to ethene via VC, competitive inhibition between different chloroethene electron accepters, and competition for H$_2$ between dechlorination and methanogens. Model simulations suggest first, that PCE dechlorinators are better competitive with methanogens than cDCE dechlorinators. Second, not only the initial relative population size of dehalogenators and H$_2$-utilizing methanogens but also electron donor delivery strategies used greatly affects the degree of dehalogenation. As a result, all of factors in the above must be considered in order to achieve economical and successful bioremediation of contaminated soil and groundwater with chlorinated solvents.

• 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.

• BMB Reports
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• 제31권5호
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• pp.519-523
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• 1998

We have previously reported that anti-glucose-6-phosphate dehydrogenase (G6PD) serum raised against native G6PD (nG6PD) enzyme recognized nG6PD antigen poorly in competitive enzyme-linked immunosorbent assay (ELISA) (Kim, 1997). In the present study, we investigated whether anti-G6PD serum raised against nG6PD can react with denatured G6PD effectively in competitive ELISA. We used partially active G6PD (paG6PD) by repeated freeze-thawing or SDS-denatured G6PD (SDS-G6PD) as both immobilized and soluble antigens, and anti-G6PD serum raised against nG6PD for competitive ELISA. The polystyrene cuvettes coated with either paG6PD or SDS-G6PD were challenged with a mixture of a limiting amount of anti-G6PD serum and various doses of paG6PD or SDS-G6PD as competitors, followed by incubation with alkaline phosphatase-anti-IgG conjugate. The competitive ELISA with paG6PD or SDS-G6PD antigen exhibited the sigmoidal dose-response curve characteristic of competition immunoassays. Furthermore, Triton-denatured G6PD (Triton-G6PD) was used in competitive ELISA. The paG6PD, SDS-G6PD, or Triton-G6PD used as competitors increased the inhibition of antibody binding to immobilized either of nG6PD or denatured G6PD compared with nG6PD competitor. The inhibition by denatured G6PD competitors was more pronounced at high competitor concentrations than at low counterparts. We conclude that anti-G6PD serum raised against nG6PD can effectively react with denatured G6PD in competitive ELISA and that our anti-G6PD serum recognizes denatured enzymes better than active enzymes.

• 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.

• Clinical Endoscopy
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• 제57권4호
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• pp.417-423
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• 2024

Since the introduction of vonoprazan, a potassium-competitive acid blocker (P-CAB), it has been demonstrated to reversibly inhibit gastric acid secretion by engaging in potassium-competitive ionic binding to H⁺/K⁺-ATPase. In contrast, proton pump inhibitors (PPIs) achieve H⁺/K⁺-ATPase inhibition through covalent binding to cysteine residues of the proton pump. Reported cases have indicated an emerging trend of P-CAB-related gastropathies, similar to those associated with PPIs, as well as unique gastropathies specific to P-CAB use, such as the identification of web-like mucus. Pathologically, parietal cell profusions, which show a positively correlated with hypergastrinemia, have a higher incidence in P-CAB users compared to PPI users. Thus, this review aims to summarize the endoscopic and pathological findings reported to date concerning P-CAB-related gastric mucosal lesions. Additionally, it seeks to discuss the differences between the PPIs and P-CABs in terms of the formation and frequency of associated gastropathies. This review highlights the evident differences in the mechanism of action and potency of acid inhibition between P-CABs and PPIs, notably contributing to differences in the formation and frequency of associated gastropathies. It emphasizes the necessity to distinguish between P-CAB-related and PPI-related gastropathies in the clinical setting.

• 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.

• Journal of Microbiology and Biotechnology
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• 제25권9호
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• pp.1425-1428
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• 2015

Monoamine oxidase (MAO) is found in most cell types and catalyzes the oxidation of monoamines. Three anithiactins (A-C, modified 2-phenylthiazoles) isolated from Streptomyces sp. were tested for inhibitory activity of two isoforms, MAO-A and MAO-B. Anithiactin A was effective and selective for the inhibition of MAO-A, with an IC₅₀ value of 13.0 μM; however, it was not effective for the inhibition of MAO-B. Anithiactins B and C were weaker inhibitors for MAO-A and MAO-B. Anithiactin A was a reversible and competitive inhibitor for MAO-A with a K_i value of 1.84 μM. The hydrophobic methyl substituent in anithiactin A may play an important role in the inhibition of MAO-A. It is suggested that anithiactin A is a selective reversible inhibitor for MAO-A, with moderate potency, and can be considered a new potential lead compound for further development of novel reversible inhibitors for MAO-A.

• 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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• 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.