• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.523-526
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• 2000

A novel cell surface display system was developed by employing the Escherichia coli outer membrane protein C (OmpC) as an anchoring motif. Poly-histidine (poly-His) peptides of 19, 32, 45, 84, and 162 amino acids (aa) could be successfully displayed by inserting them into the seventh exposed loop(L7) of OmpC. Recombinant cells displaying poly-His of 19, 32, 45, and 84 aa could absorb 18.9, 23.9, 26.1, and 32.0 ${\mu}mol$ of $Cd^{2+}$ per gram cell dry weight, respectively and therefore, would be useful as the biosorbents of heavy metals.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.56-57
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• 2006

The ultra pH-sensitive polymeric mixed micelles based on poly(L-histidine) chemistry and constructed from block copolymers containing polyHis, present four functionalities as decreasing pH: ligand exposure at pH 7.0, micelle destabilization below pH 6.8, enhanced DOX release and endosomal membrane disruption. The first functionality is expected to endow tumor pH specificity to nonspecific ligands and the rest ones may help to treat solid tumors that are hard-to-treat by conventional chemotherapy (resistant tumors). The concept was proven in vitro studies and in vivo model.

• Biomolecules & Therapeutics
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• v.24 no.5
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• pp.453-468
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• 2016

There is a conserved ATPase domain in topoisomerase II (topo II) and heat shock protein 90 (Hsp90) which belong to the GHKL (gyrase, Hsp90, histidine kinase, and MutL) family. The inhibitors that target each of topo II and Hsp90 are intensively studied as anti-cancer drugs since they play very important roles in cell proliferation and survival. Therefore the development of dual targeting anti-cancer drugs for topo II and Hsp90 is suggested to be a promising area. The topo II and Hsp90 inhibitors, known to bind to their ATP binding site, were searched. All the inhibitors investigated were docked to both topo II and Hsp90. Four candidate compounds as possible dual inhibitors were selected by analyzing the molecular docking study. The pharmacophore model of dual inhibitors for topo II and Hsp90 were generated and the design of novel dual inhibitor was proposed.

• Journal of Microbiology and Biotechnology
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• v.17 no.4
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• pp.681-684
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• 2007

An immunoassay method was developed to quantitatively detect phosphinothricin-N-acetyltransferase (PAT) encoded by the Bialaphos resistance (bar) gene in genetically modified (GM) pepper. The histidine-tagged PAT was overexpressed in Escherichia coli M15 (pQE3l-bar) and efficiently purified by $Ni^{2+}$ affinity chromatography. A developed sandwich enzyme-linked immunosorbent assay (S-ELISA) method (detection limit: $0.01{\mu}g/ml$) was 100-fold more sensitive than a competitive indirect ELISA (CI-ELISA) method or Western blot analysis in detecting the recombinant PAT. In real sample tests, PAT in genetically modified herbicide-tolerant (GMHT) peppers was successfully quantified [$4.9{\pm}0.4{\mu}g/g$ of sample (n=6)] by the S-ELISA method. The S-ELISA method developed here could be applied to other GMHT crops and vegetables producing PAT.

• YAKHAK HOEJI
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• v.40 no.1
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• pp.65-71
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• 1996

Characterization of Polyphenol oxidase (PPO) in Perillae Folium, particullarly inhibitor studies were investigated. This enzyme was stable at pH 5.0 and the residual activity of PPO at ${\geq}$ ph 5.5 was estimated to be very low. PPO activity was decreased slightly by adding amino acid with catechol as a substrate, particullary PPO activity was inhibited markedly by cystein, histidine, lysine and arginine. In the absorption spectra of the product formed when catechol was oxidized by PPO, with a ${\lambda}_{max}$ at 410nm, the peak shifted toward ${\lambda}_{max}$ 520nm by addition of L-proline. At relatively low concentrations($10^{-3}M$), sulfite and dithiothreithol completely inhibited PPO activity. Inhibition of PPO activity by amino acids and inhibitors increased or decreased depending on the pH used to measure it.

• Proceedings of the Korean Biophysical Society Conference
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• 1996.07a
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• pp.45-45
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• 1996

Flavin-peptides were purified from pyranose oxidase (EC 1.1.3.10) after tryptic- chymotryptic and tryptic digestion. The spectral and chromatographic properties of these flavin peptides showed that the FAD of pyranose oxidase appears to be bound, by way of the 8${\alpha}$-methylene group, to the N-l position of the imidazole ring of the histidine. Automated sequence analysis showed that the amino acid sequence of the tryptic-chymotryptic flavin-peptide from pyranose oxidase is Ser-Thr-X-Trp and that of the tryptic flavin-peptide is Met-Ser-Thr-X-Trp. (omitted)

• Journal of Microbiology and Biotechnology
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• v.22 no.11
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• pp.1518-1522
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• 2012

Leuconostoc mesenteroides is a heterofermentative Grampositive bacterium that plays key roles in fermentation of foods such as kimchi, sauerkraut, and milk, leading to the production of various organic acids and aromatic compounds. To study the microbiological and genomic characteristics of L. mesenteroides, we have developed a new chemically defined minimal medium by using the single omission technique. During the exponential cell growth, this species required glutamine, methionine, valine, and nicotinic acid as essential nutrients and 8 amino acids (arginine, cysteine, histidine, leucine, phenylalanine, proline, threonine, and tryptophan), 5 vitamins (ascorbic acid, folic acid, inosine, calcium panthothenate, and thiamine), and others (manganese, magnesium, adenine, uracil, and Tween 80) as supplemental nutrients. This medium is useful to study the metabolic characteristics of L. mesenteroides and to explain its role in food fermentation.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.301-304
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• 2005

S-Adenosyl-L-Methionine(SAM) has an important role for DNA methylation and cell signaling. SAM was synthesized from methionine and ATP by SAM synthetase and play an pivotal function in the primary and secondary metabolism of cells. Recent studies have revealed in the effect of SAM in case of morphological differentiation in both eukaryotes and prokaryotes. We isolated SAM gene from Saccharomyces cerevisiae and cloned it into expression vector for E. coli respectively. An 1.15 kb SAM-s gene fragment was isolated by Low-strigency PCR using ORF primer. By the analysed primary sequence deduced from DNA sequence, this gene included conserved domains similar with other well-known SAM synthetase. First of all, SAM synthetase gene cloned pGEM-T vector and subcloned into histidine tagging system to purify the expressed protein using metal chelating resin. Typical characteristic analysis of this enzyme is underway.

• Journal of Marine Bioscience and Biotechnology
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• v.10 no.1
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• pp.18-25
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• 2018

Chlorella is quantitatively and qualitatively high in protein with balanced essential amino acid profiles, vitamins and minerals. ${\gamma}-Aminobutyric$ acid (GABA) is broadly distributed in nature and fulfills multi-physiological functions including effect such as a health-promoting functional compound. To improve the GABA production, Chlorella protothecoides were grown through the modified mixtrophic culture medium containing 2L of sterilized bristol medium with 0.01% urea and 4.0% glucose in a 5L fermenter. The results showed that nineteen kinds of amino acid including GABA at C. protothecoides sample were analyzed using high performance liquid chromatography (HPLC). Glutamic acid in total concentration (%) of amino acid is the most abundant amino acid (33.10%), followed by alanine (20.48%) and GABA (17.48%). Three amino acids including GABA were responsible for more than 70% total concentration in C. protothecoides sample including eight essential and nine non-essential amino acids: aspartic acid, asparagine, serine, glutamine, histidine, glycine, threonine, arginine, tyrosine, valine, methionine, tryptophan, phenylalanine, isoleucine, leucine, lysine. As a result of this experiment, it is expected that Chlorella will be developed to a critical product having high value as, GABA, functional food materials.

• The Korean Journal of Nuclear Medicine
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• v.17 no.2
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• pp.71-77
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• 1983

Amino acids such as L-tyrosine, L-histidine, and tryptophan, which bear an aromatic ring in the molecule, could successfully be labelled by radioactive iodine through arylthallium ditrifluoroacetate intermediate. Generally, the labelling reaction could proceed in a short labelling time(ca, 20 minutes) and resulted in a high labelling yields and purity of the labelled product. This procedure has, therefore, been proved to be effective as the labelling method of short labelling time and high specific activity. Labelling proteins such as oval albumin and human albumin could also be achieved in $34\sim48%$ net labelling yield by thallating them at the low temperature $(0\sim10^{\circ}C)$, whereas the labelled products were mainly composed of various denatured products by thallating them at the high temperature$(35\sim40^{\circ}C)$, though the radioactivity was highly retained in the labelled products. Uracil and hippuric acid could also be labelled in a short labelling time though their thallation required a prolonged heating procedure. It was proved that this procedure may be effective to label these compounds by short lived radioisotopes. The labelling yields were, however, lower than 30%.