• Journal of Microbiology and Biotechnology
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• 제20권4호
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• pp.737-748
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• 2010

Glutaminase production in Zygosaccharomyces rouxii by solid-state fermentation (SSF) is detailed. Substrates screening showed best results with oatmeal (OM) and wheatbran (WB). Furthermore, a 1:1 combination of OM:WB gave 0.614 units/gds with artificial sea water as a moistening agent. Evaluation of additional carbon, nitrogen, amino acids, and minerals supplementation was done. A central composite design was employed to investigate the effects of four variables (viz., moisture content, glucose, corn steep liquor, and glutamine) on production. A 4-fold increase in enzyme production was obtained. Studies were undertaken to analyze the time-course model, the microbial growth, and nutrient utilization during SSF. A logistic equation ($R^2$=0.8973), describing the growth model of Z. rouxii, was obtained with maximum values of ${\mu}_m$ and $X_m$ at $0.326h^{-1}$ and 7.35% of dry matter weight loss, respectively. A goodfit model to describe utilization of total carbohydrate ($R^2$=0.9906) and nitrogen concentration ($R^2$=0.9869) with time was obtained. The model was used successfully to predict enzyme production ($R^2$=0.7950).

• KSBB Journal
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• 제9권1호
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• pp.40-47
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• 1994

Fructosyltransferase와 glucose oxidase의 혼합효소계를 이용한 고순도 fructo-oligosaccharides 생산반응에서의 수학적 모델을 제안하고 실험적으로 검증한 결과 실험치와 모델 값이 서로 잘 일치하였다. 혼합 효소계에서 두 효소의 kinetic parameters를 구한 결과, fructosyltransferase 단일 효소계에서의 값들에 비해 $K_m$ 값들은 감소하였고, $K_m,\;V_{max}$값들은 증가하였다. 혼합 효소계의 반응메카니즘은 전체적으로 Michaelis-Menten kinetics로 표현할 수 있었고, 제안된 모델을 이용하여 고순도 fructo-oligosaccharides 생산에 이상적인 설탕농도를 예측할 수 있었다.

• Archives of Pharmacal Research
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• 제19권5호
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• pp.348-352
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• 1996

The antioxidant efficacy of aspalatone, a new antithrombotic agent, has been recognized in the neurotoxic model and in the cardiotoxic model in proliminary studies. We examined the specific activity of antiosidnat enzyme in the rat blood following administrations of aspirin, maltol, aspirin together with maltol, salicylmaltol (major metabolite of aspalatone) and aspalatone, respectively. Our assessment showed that salicylmaltol, maltol, aspalatone enhanced antiperoxidative activity. In addition, neither aspirin nor combination of aspirin and maltol, showed any significant effect on the activity of antioxidant enzyme. Because $H_{2}$$O_{2}$ accumulation may stimulate the thrombogenesis in blood, the result suggests that the induction of blood antiperoxidative activity produced by aspalatone may have beneficial effects on the thrombogenesis.

• Bulletin of the Korean Chemical Society
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• 제24권7호
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• pp.931-936
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• 2003

By the use of multi-loop thermodynamic boxes developed here by us, we show that models of enzyme catalysis (e.g., split-site model) developed in an attempt to emphasize the importance of the reactant-state destabilization and, thus, demonstrate misleading nature of the fundamentalist position which defines Pauling's transition-state stabilization as the entire and sole source of enzyme catalytic power, should be reduced to the fundamentalist formulation which completely neglects dynamical aspects of mechanism between the reactant and the transition states and dwells only on events restricted to the reactant and transition states alone, because the splitsite (and other canonical) formulations as well as fundamentalist formulations are based, in common, on equilibrium assumptions stipulated by the thermodynamic box logics. We propose to define the equilibrium assumptions as the requisite and sufficient conditions for the fundamentalist position to enjoy its primacy as central dogma, but not as sufficient conditions for its validity, because it is subjected to contradictions presented by existing data.

• 전기전자학회논문지
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• 제21권3호
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• pp.309-319
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• 2017

The research investigates the inhibition of fatty acid biosynthesis of the human Acetyl-CoA Carboxylase enzyme by the aromatic-structure inhibitors (also known as ligands) containing variables of substituents, contributing an important role in the treatment of fatty-acid metabolic syndrome expressed by the group of cardiovascular risk factors increasing the incidence of coronary heart disease and type-2 diabetes. The effective interoperability between ligand and enzyme is characterized by a 50% concentration of enzyme inhibitor ($IC_{50}$) which was determined by experiment, and the factor of geometry structure of the ligands which are modeled by quantum mechanical methods using HyperChem 8.0.10 and Gaussian 09W softwares, combining with the calculation of quantum chemical and chemico-physical structural parameters using HyperChem 8.0.10 and Padel Descriptor 2.21 softwares. The result data are processed with the combination of classical statistical methods and modern bioinformatics methods using the statistical softwares of Department of Pharmaceutical Technology - Jadavpur University - India and R v3.3.1 software in order to accomplish a model of the quantitative structure - activity relationship between aromatic-structure ligands inhibiting fatty acid biosynthesis of the human Acetyl-CoA Carboxylase.

• Bulletin of the Korean Chemical Society
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• 제26권6호
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• pp.971-974
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• 2005

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.212.2-212.2
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• 2003

Primary cultured rat hepatocytes injured by carbon tetrachloride as a model to screen for hepatoprotective effect. Four flavonoid compounds showed anti-hepatotoxic effect by decrease GPT. LDH activity and MDA level. Also screen for hepatoprotective, anti-oxidative and anti-apoptosis effects of baicalin and baicalein on chang cell treated with t-BHP. Mesured radical detoxifying enzyme, GST and antioxidant enzyme SOD, Catalase activity, GSH level and Cellular glutathion peroxidase activity. (omitted)

• KSBB Journal
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• 제11권2호
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• pp.186-192
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• 1996

The effects of chemical modification on the enzymes' stability in polar organic solvents were studied with subtilisin Carlsberg in dimethylformamide-water mixtures as a model system. Three out of nine lysine residues of subtilisin Carlsberg were coupled to either trimellilic or pyromellitic anhydrides thereby, for each lysine residue modified, resulting in the net replacement of one basic amino group by two or three acidic carboxyl groups, respectively. In water at 60$^{\circ}C$, both trimellitic and pyromellitic anhydride-modified subtilisin Carlsberg showed increased thermostability by 2.6 times and 1.6 times, respectively, as compared to that of unmodified enzyme. In 70% dimethylformamide at 25$^{\circ}C$, however, only pyromellitic acrid was shown to enhance the stability of subtilisin Carlsberg by 5.5 times increasing the half life time of irreversible inactivation from 4.9hr for unmodified enzyme to 27.8hr for modified enzyme.

• BMB Reports
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• 제30권3호
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• pp.211-215
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• 1997

A photoactive analog of ATP, 3'(2')-O-(p-azidobenzoyl)-adenosine 5-triphosphate (AB-ATP) was synthesized by chemically coupling N-hydroxysuccinimidyl-4-azidobenzoate (NHS-AB) and ATP. The utility of AB-ATP as an effective active-site-directed photoprobe was demonstrated using catalytic subunit of protein kinase A as a model enzyme. Photoincorporation of AB-ATP was saturated with apparent dissociation constant of $30{\mu}m$ and protected completely by $100{\mu}m$ of ATP. When the enzyme was covalently modified by photolysis in the presence of saturating amounts of photoprobe, about 60% inhibition of enzyme activity was observed. These results demonstrate that AB-ATP has potential application as a probe to characterize ATP-binding proteins including protein kinases.

• 한국미생물·생명공학회지
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• 제23권4호
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• pp.416-424
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• 1995

Mechanism of the cyclodextrin (CD) production reaction by cyclodextrin glucanotransferase (CGTase) using swollen extrusion starch as substrate was investigated emphasizing the structural features of starch granule. The degree of gelatinization was identified to be the most representative structural characteristic of swollen starch. The most suitable degree of gelatinization of swollen starch for CD production was around 63.52%. The structural transformation of starch granule during enzyme reaction was also followed by measuring the changes of the degree of gelatinization, microcrystallinity, and accessible and inaccessible portion to CGTase action of residual swollen starch. The adsorption phenomenon of CGTase to swollen starch was also examined under various conditions. The inhibition mechanism of CGTase by various CDs was identified to be competitive, most severely by a-CD. The mechanism elucidated will be used for development of a kinetic model describes CD production reaction in heterogeneous enzyme reaction system utilizing swollen extrusion starch.