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Byung-Gee Kim

Bio: Byung-Gee Kim is an academic researcher from Seoul National University. The author has contributed to research in topics: Streptomyces coelicolor & Chemistry. The author has an hindex of 52, co-authored 382 publications receiving 9479 citations. Previous affiliations of Byung-Gee Kim include New Generation University College & Chungnam National University.


Papers
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Journal ArticleDOI
TL;DR: A beacon aptamer-based biosensor for the detection of thrombin was developed using electrochemical transduction method and the peak signal of the MB is clearly decreased by the binding ofThrombin onto the beacon apt AMER, indicating a decrease in electrical current intensity in voltamogram.

246 citations

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TL;DR: In this article, an asymmetric synthesis of chiral amines using prochiral ketones was carried out with (S)-specific omega-transaminase (omega-TA) from Vibrio fluvialis JS17.
Abstract: The asymmetric synthesis of chiral amines using prochiral ketones was carried out with (S)-specific omega-transaminase (omega-TA) from Vibrio fluvialis JS17. This reaction is inhibited severely by both products, (S)-amine and deaminated ketone. In addition, thermodynamic equilibrium strongly favored the reverse reaction. L-Alanine proved to be the best amino donor based on easy removal of the products. Optimal pH of the reactions with both whole cells and cell-free extract was 7. Amino acceptor reactivities of ketone substrates and reaction profiles of the asymmetric synthesis showed that the initial rate as well as the reaction yield were lower when the resulting (S)-amine from a prochiral ketone substrate was a more reactive amino donor. The yield could be increased dramatically by removing pyruvate, which is a more inhibitory product than (S)-alpha-methylbenzylamine [(S)-alpha-MBA] when acetophenone and L-alanine are used as an amino acceptor and donor, respectively. The removal of pyruvate was carried out by incorporating lactate dehydrogenase (LDH) in cell-free extract or by using whole cells. The whole cell reaction yielded a much better result. When 25 mM benzylacetone and 30 mM acetophenone were used as an amino acceptor with 300 mM L-alanine, 90.2% and 92.1% of the reaction yields after 1 day were obtained with whole cells, respectively. Enantiomeric excesses of both (S)-alpha-MBA and (S)-1-methyl-3-phenylpropylamine [(S)-MPPA] were all above 99%.

211 citations

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TL;DR: LEM can provide functional biomaterial platforms for diverse applications in liver tissue engineering by promoting survival and maturation of hepatocytes and hepatic commitment of stem cells.

200 citations

Journal ArticleDOI
TL;DR: The active site model of the amine:pyruvate aminotransferase from Vibrio fluvialis JS17 successfully explains the observed substrate specificity as well as the stereoselectivity of the APA.
Abstract: An active site model of the amine:pyruvate aminotransferase (APA) from Vibrio fluvialis JS17 was constructed on the basis of the relationship between substrate structure and reactivity. Due to the broad substrate specificity of the APA, various amino donors (chiral and achiral amine, amino acid, and amino acid derivative) and amino acceptors (keto acid, keto ester, aldehyde, and ketone) were used to explore the active site structure. The result suggested a two-binding site model consisting of two pockets, one large (L) and the other small (S). The difference in the size of each binding pocket and strong repulsion for a carboxylate in the S pocket were key determinants to control its substrate specificity and stereoselectivity. The L pocket showed dual recognition mode for both hydrophobic and carboxyl groups as observed in the side-chain pockets of aspartate aminotransferase and aromatic aminotransferase. Comparison of the model with those of other aminotransferases revealed that the L and S pockets corresponded to carboxylate trap and side-chain pocket, respectively. The active site model successfully explains the observed substrate specificity as well as the stereoselectivity of the APA.

164 citations

Journal ArticleDOI
TL;DR: Nucleotide resolution genome-scale measurements of the transcriptome and translatome of Streptomyces coelicolor, the model antibiotic-producing actinomycete, are integrated and it is revealed that the translation efficiency of secondary metabolic genes is negatively correlated with transcription and that several key antibiotic regulatory genes are translationally induced at transition growth phase.
Abstract: Individual Streptomyces species have the genetic potential to produce a diverse array of natural products of commercial, medical and veterinary interest. However, these products are often not detectable under laboratory culture conditions. To harness their full biosynthetic potential, it is important to develop a detailed understanding of the regulatory networks that orchestrate their metabolism. Here we integrate nucleotide resolution genome-scale measurements of the transcriptome and translatome of Streptomyces coelicolor, the model antibiotic-producing actinomycete. Our systematic study determines 3,570 transcription start sites and identifies 230 small RNAs and a considerable proportion (∼21%) of leaderless mRNAs; this enables deduction of genome-wide promoter architecture. Ribosome profiling reveals that the translation efficiency of secondary metabolic genes is negatively correlated with transcription and that several key antibiotic regulatory genes are translationally induced at transition growth phase. These findings might facilitate the design of new approaches to antibiotic discovery and development.

153 citations


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TL;DR: Different methods for the immobilization of enzymes are critically reviewed, with emphasis on relatively recent developments, such as the use of novel supports, e.g., mesoporous silicas, hydrogels, and smart polymers, novel entrapment methods and cross-linked enzyme aggregates (CLEAs).
Abstract: Immobilization is often the key to optimizing the operational performance of an enzyme in industrial processes, particularly for use in non-aqueous media. Different methods for the immobilization of enzymes are critically reviewed. The methods are divided into three main categories, viz. (i) binding to a prefabricated support (carrier), (ii) entrapment in organic or inorganic polymer matrices, and (iii) cross-linking of enzyme molecules. Emphasis is placed on relatively recent developments, such as the use of novel supports, e.g., mesoporous silicas, hydrogels, and smart polymers, novel entrapment methods and cross-linked enzyme aggregates (CLEAs).

1,857 citations

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TL;DR: This work reviews strategies for natural product screening that harness the recent technical advances that have reduced technical barriers and assess the use of genomic and metabolomic approaches to augment traditional methods of studying natural products.
Abstract: Natural products have been a rich source of compounds for drug discovery. However, their use has diminished in the past two decades, in part because of technical barriers to screening natural products in high-throughput assays against molecular targets. Here, we review strategies for natural product screening that harness the recent technical advances that have reduced these barriers. We also assess the use of genomic and metabolomic approaches to augment traditional methods of studying natural products, and highlight recent examples of natural products in antimicrobial drug discovery and as inhibitors of protein-protein interactions. The growing appreciation of functional assays and phenotypic screens may further contribute to a revival of interest in natural products for drug discovery.

1,822 citations

Journal ArticleDOI
TL;DR: This review summarizes the most recent advances in the field over the past 4 years, specifically highlighting new and interesting discoveries in tissue engineering and drug delivery applications.
Abstract: Utilization of polymers as biomaterials has greatly impacted the advancement of modern medicine. Specifically, polymeric biomaterials that are biodegradable provide the significant advantage of being able to be broken down and removed after they have served their function. Applications are wide ranging with degradable polymers being used clinically as surgical sutures and implants. In order to fit functional demand, materials with desired physical, chemical, biological, biomechanical and degradation properties must be selected. Fortunately, a wide range of natural and synthetic degradable polymers has been investigated for biomedical applications with novel materials constantly being developed to meet new challenges. This review summarizes the most recent advances in the field over the past 4 years, specifically highlighting new and interesting discoveries in tissue engineering and drug delivery applications.

1,712 citations