• The Korean Journal of Food And Nutrition
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• v.23 no.2
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• pp.171-177
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• 2010

The catabolic threonine dehydratase from Serratia marcescens ATCC 25419 was purified to homogeniety using Sephadex G-200 gel filtration and AMP-Sepharose 4B affinity chromatography. The molecular weight of the native enzyme was 120,000 by native pore gradient PAGE. The enzyme was composed of four identical subunits with subunit molecular weights of 30,000 by SDS-PAGE. The Km values of the enzyme for L-threonine with and without AMP were 7.3 and 92 mM, respectively. There were 2 moles of pyridoxal phosphate and 16 moles of free -SH groups per 1 mole of enzyme. The enzyme was inhibited by $\alpha$-ketobutyrate, pyruvate, glyoxylate, and phosphoenol pyruvate(PEP) in the presence of AMP, yet stimulated by cAMP and ADP. For enzyme properties in comparison with S. marcescens, E. coli, and S. typhimurium enzyme, such as the PLP content, number of free sulfhydryl groups, and existence of ADP binding site, the S. marcescens enzyme was more similar to the S. typhimurium enzyme than the E. coli enzyme. Of the three enteric bacteria, the E. coli and S. typhimurium enzyme was increased the activity by ADP and cAMP, respectively, but only the S. marcescens enzyme was increased the activity by both ADP and cAMP. Therefore, the subtle differences in the properties between enzymes from the three enteric bacteria may represent minor structural differences among these enzymes and warrants further study.

• BMB Reports
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• v.49 no.12
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• pp.681-686
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• 2016

Fructose 1,6-bisphosphate aldolase (FBA) is important for both glycolysis and gluconeogenesis in life. Class II (zinc dependent) FBA is an attractive target for the development of antibiotics against protozoa, bacteria, and fungi, and is also widely used to produce various high-value stereoisomers in the chemical and pharmaceutical industry. In this study, the crystal structures of class II Escherichia coli FBA (EcFBA) were determined from four different crystals, with resolutions between $1.8{\AA}$ and $2.0{\AA}$. Native EcFBA structures showed two separate sites of Zn1 (interior position) and Zn2 (active site surface position) for $Zn^{2+}$ ion. Citrate and TRIS bound EcFBA structures showed $Zn^{2+}$ position exclusively at Zn2. Crystallographic snapshots of EcFBA structures with and without ligand binding proposed the rationale of metal shift at the active site, which might be a hidden mechanism to keep the trace metal cofactor $Zn^{2+}$ within EcFBA without losing it.

• Proceedings of the Korean Biophysical Society Conference
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• 2003.06a
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• pp.62-62
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• 2003

The native form of serpin (serine protease inhibitor) is kinetically trapped in metastable state. Metastability in these proteins is critical to their biological function. Serpins inhibit target proteases by forming a stable covalent complex in which the cleaved reactive site loop of the serpin is inserted into $\beta$-sheet A of the serpin with concomitant translocation of the protease to the opposite of the initial binding site. Despite recent determination of the crystal structures of a Michaelis protease-serpin complex as well as a stable covalent complex, details on the kinetic mechanism remain unsolved. In this study we constructed several $\alpha$$_1$-antitrypsin variants and examined their kinetic mechanism of loop translocation and formation of protease-serpin complex by stopped-flow experiments of fluorescence resonance energy transfer as well as quenched-flow experiment. We report here the relationship of serpin's conformational switch mechanism with Inhibitory activity. There is little direct correlation between loop insertion rate and inhibitory activity. Rather, disrupting a salt bridge between R196 and E354 accelerates loop translocation even though it impairs the inhibitory activity. Moreover, the serpin's reactive site loop is translocated, at least partially, prior to loop cleavage.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.244-244
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• 2015

Managed Aquifer Recharge (MAR) in the form of Aquifer Storage and Recovery (ASR) systems are being applied for numerous water augmentation projects both in developed and developing countries. Given the onset of Climate Change and its influence on weather patterns and land use, it has been acknowledged the utilization of this technology will be ever increasing. This technique like all others does have its drawbacks or disadvantages, whereby to overcome these drawbacks or disadvantages it is recommended that logical planning process be followed. In this study, we developed a decision framework known as "Decision framework for the planning, designing, construction/testing and implementation of subsurface water storage system" to further standardize the planning and design process of subsurface water storage system to increase the probability of having a successful ASR/ASTR project. The formulation of this framework was based on earlier frameworks, guidelines, published papers and technical reports which were compiled into a data collection database. The database of which consider both qualitative and quantitative aspect for example recharge objectives, site location, water chemistry of the native, source and recovered water, aquifer characteristics(hydraulic conductivity, transmissivity, porosity), injection/pumping rate, ecological constraints, societal restrictions, regulatory restrictions etc. The assimilation of these factors into a singular framework will benefit the broad spectrum of stakeholder as it maps the chronological order under which ASR project should be undertaken highlighting at each stage the feasibility of the project. The final stage of which should result in fully operational ASR system. The framework was applied to two case studies and through the application of a modified ASR site selection suitability index (Brown et al., 2005) a score was derived to identify the performance of each site. A high score of which meant a maximize chance of success given the reduce presence of project constraints.

• The Korean Journal of Ecology
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• v.16 no.4
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• pp.377-395
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• 1993

Habitat types, community structure and population characteristics of Koelreuteria paniculata were investigated in Mt. Wolak, Chungbuk and Naesokdong, Daegu, which are natural habitats of the species in inland region of Korea, and its origin was discussed. Habitats of Koelreuteria paniculata were classified to 3 types: sand bar formed by the sands flooded in the course of flow of the mountain stream (Type 1). crevice on the rock bed within the mountain stream (Type 2) and crevice of the rock around the edge of mountain stream (Type 3). Most Koelreuteria paniculata communities in Mt. Wolak site were composed of 3 layers of subtree layer, shrub layer and herb layer and that of Daegu site was 4 layers including tree layer. In the floristic composition of the Koelreuteria paniculata community, plants occurring frequently in the wet and open site, such as Zelkova serrata and Fraxinus rhynchoph-vlla showed high frequency. Frequency distribution of diameter at ground surface of Koelreutrria paniculata showed reversed J-shaped type. It was supposed that expansion of Koelreuteria paniculata community in Mt. Wolak site might be accomplished by the flow of the stream. Many saplings capable of becoming a successor of mature trees in Daegu site in near degenerating phase were established on the forest floor of the Koelreuteria paniculata community. From this result, it was supposed that these saplings originated from the seeds dispersed from a seed tree might form the Koelreuteria paniculata community of the next generation. On the other hand, the origin of Koelreutevia paniculata in inland sites was explained by two hypotheses: the one was that Koelreuteria paniculata might be transplanted by human and the other was that the present site might be native habitat of the community.

• Journal of the Korean Institute of Landscape Architecture
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• v.50 no.4
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• pp.1-19
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• 2022

This study aims to discover the implications through the analysis of the characteristics and design strategies of the regeneration of the post-industrial sites in the metropolitan the Beijing-Tianjin-Tangshan region. This study provides a basis for future research and theoretical strengths for post-industrial site regeneration practices. The results of the study are as follows. First, post-industrial site regeneration projects pursue diverse goals such as industrial heritage preservation, cultural creativity, and neighborhood revitalization in the Beijing-Tianjin-Tangshan region. Second, in the design process, the characteristics and spatial levels of the space are enhanced by utilizing the original industrial space, incorporating transitional space, and using industrial facilities of varying heights. Third, old and new landscape elements are harmoniously integrated through the rational use of industrial relics and the appropriate addition of new elements. Fourth, the design emphasizes ecological soil restoration and the use of native and adaptable plants that have the capacity to remediate polluted soil. Fifth, the design combines modern artistic elements, such as sculpture and graffiti art to enrich the site and promote the revival of the post-industrial site. Sixth, urban events and public activities are actively programmed to vitalize the regenerated site.

• Journal of Microbiology and Biotechnology
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• v.17 no.8
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• pp.1385-1389
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• 2007

5-Enolpyruvylshikimate-3-phosphate (EPSP) synthase catalyzes the formation of EPSP and inorganic phosphate from shikimate-3-phosphate (S3P) and phosphoenolpyruvate (PEP) in the biosynthesis of aromatic amino acids. To delineate the domain-specific function, we successfully isolated the discontinuous C-terminal domain (residues 1-21, linkers, 240-427) of EPSP synthase (427 residues) by site-directed mutagenesis. The engineered C-terminal domains containing no linker (CTD), or with gly-gly ($CTD^{GG}$) and gly-ser-ser-gly ($CTD^{GSSG}$) linkers were purified and characterized as having distinct native-like secondary and tertiary structures. However, isothermal titration calorimetry (ITC), $^{15}N-HSQC$,\;and\;^{31}P-NMR$ revealed that neither its substrate nor inhibitor binds the isolated domain. The isolated domain maintained structural integrity, but did not function as the half of the full-length protein.

• Journal of the Korean Institute of Landscape Architecture
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• v.22 no.2
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• pp.133-157
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• 1994

This study was executed to find out the succession stage and the ecological niche of Lindera erythrocarpa Markino. Four sites were selected by field investigation. They are Jeondungsa and Jeongsusa of Kanghwa Island, Mt. Suri of Anyang and Mt. Gaya of Chungcheongnamdo. They located in the region which have the similar temperature with Seoul region or lower average temperature for winter than that of adjacent Seoul. In the four sites, L, erythrocarpa was appeard in canopy layer at L. erythrocarpa community in Jeondungsa, L. erythrocarpa-Q. serrata, Z. serrata-L. erythrocarpa community in Jeongsusa, Castanea crenata-L, erythrocarpa community, L. erythrocarpa-Q. serrata community in Mt. Gaya and in the rest of the sites, it lives in subtree and shrub layer. And in the four sites but Jeongsusa area, it correspond with Chang(1991)'s study that L. erythrocarpa is dominant species in the site impacted by human. L. erythrocarpa lives with Quercus spp. such as Q. serrata, Q. variabilis, Q. mongolica and Carpinus laxiflora but it's presumably a passing phenomena.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.761-762
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• 2003

Recently, several studies have reported on the successful repair of osteochondral defects by transplantation of cultured chondrocytes, but the method requires a sufficient number of cells obtained from the donor site in the articular cartilage. This can potentially be overcome by the use of undifferentiated or partially developed cartilage precursor cells drived from early embryos and fetal tissue. Neonatal cartilage unlike adult cartilage has the capacity for rapid regeneration. the purpose of this study is to determine effective regeneration method using early cartilage precursors for tissue-engineered cartilage. Cells isolated from neonatal (immediately postpartum, 2 hours of age) SD rats were seeded onto biodegradable polymer matrices and transplanted in nude mice's subcutaneous sites for 4 and 8 weeks. Tissue-engineered cartilage showed gross and histologic evidences similar to native articular cartilage.

• BMB Reports
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• v.33 no.5
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• pp.366-369
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• 2000

The nucleotide effects of Hafnia alvei aspartase were investigated. Purine nucleosides, such as adenosine and guanosine, increased the aspartase activities; whereas, purine nucleotides, such as AMP, ATP, GTP and IMP, caused little change in the aspartase activities. However, pyrimidine derivatives, such as cytidine and CTP, decreased the aspartase activity. The nucleotide and nucleoside effects by the limited trypsin-treated aspartase were similar to those of a native enzyme. These results indicate that the COOH-terminal region and an allosteric site might be located away from each other. The initial velocity study in the presence of adenosine showed that $K_m$ for aspartate was decreased to one-sixth of that in the absence of adenosine, but $V_{max}$ was unchanged. The significance of the distinct allosteric effect for the enzyme-nucleotide interaction is discussed.