• The Korean Journal of Ecology
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• v.20 no.5
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• pp.315-321
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• 1997

Peroxidase activities and isozyme patte군 of the pine needles (Pinus densiflora) were examined and compared in the coastal regions of Anmyum-Do(Choongnam, Taean-Gun) and inland regions of Shinchang-Myun(Choongnam, Asan-City). The pine needle peroxidase from Anmyum-Do showed approximately three times higher specfic activity than Shinchang pine needle peroxidase. The pine needle extracts of Anmyun-Do and Shinchang contained three anionic isoperoxidases, named A1, A2 and A3, when subjected to starch gel electrophoresis at pH 7.0. Cjationic isoperoxidases could not be found in both extracts., However, there existed unique isoperoxidase An only from the extracts of Anmyun-Do pine needles under the salinary environment. Moreover, the specific activities of catalase and glucose-6-phosphate dehydrogenase from Anmyun-Do, known for the inducible enzymes under the stress condition, were about 1.8 times higher than those of Shinchang pine needles. However, the specific activities of other enzymes did not show great differences between the two regions. Considering the above results of the higher specific activity of peroxidase and the unique expression of isoperoxidase An, pine needle peroxidase might involve in the defence mechanism against the salinary stress of Anmyun-Do.

• Journal of Applied Biological Chemistry
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• v.48 no.4
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• pp.183-186
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• 2005

Arabidopsis AHL gene encodes a 3'(2')-phosphoadenosine 5'-phosphate (PAP)-specific phosphatase that plays a role in the sulfate activation pathway. We complemented E. coli cysQ mutant defective in cysteine biosynthesis with the AHL gene. AHL cDNA was cloned into the prokaryotic expression vector pKK388-1 and transformed into the bacterial mutant. Since cysQ mutant is a leaky cysteine auxotroph only under aerobic conditions, the bacteria were grown in liquid media with vigorous shaking to provide more aeration. In cysteine-free medium, cysQ mutant and the mutant harboring empty vector did not grow well, whereas cells harboring AHL cDNA exhibited significantly improved growth with doubling time of approximately 3 h. cysQ is known to encode a 3'(2'),5'-diphosphonucleoside 3'(2')-phosphohydrolase (DPNPase). However, our data suggest that cysQ protein has PAP-specific phosphatase activity in addition to DPNPase activity. Microbial complementation procedure described in this paper is useful for structure-activity studies of PAP-specific phosphatases identified from microbes and plants.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.1
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• pp.172-178
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• 2004

To investigated the effects of Kwibi-tang water extract (KBT) on the non-specific immune response in C57BL/6 mice stressed by immobilization, we evaluated the changes in the contents of serum histamine and corticosterone and the phagocytic activity of macrophages. The level of serum histamine and corticosterone was determined with spectrofluorometer. The cell viability was determined by a MTT assay method. The subpolpulation of lymphocytes was determined by a flow cytometry. The phagocytic activity was determined with luminometer. KBT decreased the serum level of histamine and corticosterone increased by immobilization stress. Also, KBT enhanced the phagocytic activity and decreased the level of nitric oxde in murine peritoneal macrophages decreased by immobilization stress. These results indicate that KBT may be useful for the prevention and treatment of stress via suppression of serum histamine and corticosterone level and enhancement of the non-specific immune response.

• BMB Reports
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• v.56 no.8
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• pp.451-456
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• 2023

Deubiquitinases (DUBs) are an essential component of the ubiquitin-proteasome system (UPS). They trim ubiquitin from substrate proteins, thereby preventing them from degradation, and modulate different cellular processes. Ubiquitin-specific protease 14 (USP14) is a DUB that has mainly been studied for its role in tumorigenesis in several cancers. In the present study, we found that the protein levels of USP14 were remarkably higher in gastric cancer tissues than in the adjacent normal tissues. We also demonstrated that the inhibition of USP14 activity using IU1 (an USP14 inhibitor) or the inhibition of USP14 expression using USP14-specific siRNA markedly reduced the viability of gastric cancer cells and suppressed their migratory and invasive abilities. The reduction in gastric cancer cell proliferation due to the inhibition of USP14 activity was a result of the increase in the degree of apoptosis, as evidenced by the increased expression levels of cleaved caspase-3 and cleaved PARP. Furthermore, an experiment using the USP14 inhibitor IU1 revealed that the inhibition of USP14 activity suppressed 5-fluorouracil (5-FU) resistance in GC cells. Collectively, these findings indicate that USP14 plays critical roles in gastric cancer progression and suggest its potential to serve as a novel therapeutic target for gastric cancer treatment.

• Journal of Applied Biological Chemistry
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• v.59 no.1
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• pp.75-81
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• 2016

Glutaraldehyde was used as a cross-linking agent for immobilization of purified ${\alpha}$-amylase from Exiguobacterium sp. DAU5. Befitting concentration of glutaradehyde and cross-linking time is the key to preparation of cross-linking chitosan beads. Based on optimized immobilization condition for ${\alpha}$-amylase, an overall yield of 56% with specific activity of 2,240 U/g on chitosan beads and 58% with specific activity of 2,320 U/g on chitosan-carbon beads was obtained. The optimal temperature and pH of each immobilized enzyme activity were $50^{\circ}C$ and 50 mM glycine-NaOH buffer pH 8.5, respectively. Those retained more than 75 and 90% of its maximal enzyme activity at pH 7.0-9.5 and after incubation at $50^{\circ}C$ for 1 h, respectively. In addition, the immobilization product showed higher organic-solvent tolerance than free enzymes. The mode of hydrolyzing soluble starch revealed that the ${\alpha}$-amylase possessed high hydrolyzing activity. These results indicate that chitosan is good support and has broad application prospects of enzyme immobilization.

• Microbiology and Biotechnology Letters
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• v.22 no.1
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• pp.45-51
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• 1994

Antitumor polysaccharides were known to activate complement system and to increase specific serum proteins in mouse, and researcher reported that antitumor activity of polyasccharides might be correlated with their biological properties such as activation of complement system and increase of specific protein $L_{A}$, $L_{B}$ and $L_{C}$ within the mouse serum. In case of several Ganoderma lucidum, there was no correlation between their antitumor activities and their bioloical properties, but the antitumor activities against sarcoma 180 of the alkali extracted crude polysaccharide fractions of the Ganoderma lucidum IY 009. AS, T, AI and M were correlated with their bioloical properties such as anticomplementary activity and intensity of mouse serum protein $L_{A}$, $L_{B}$ and $L_{C}$.

• BMB Reports
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• v.36 no.2
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• pp.201-206
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• 2003

Two lymphoid-specific proteins, RAG1 and RAG2, are required for the initiation of the V(D)J recombination in vitro. The V(D)J cleavage that is mediated by RAG proteins at the border between the coding and signal sequences results in the production of a hairpin at the coding end and a double-stranded break at the signal end. Two hairpin coding ends are re-opened, modified, and sealed; whereas, the signal ends are directly ligated. Here I report that only RAG1 can carry out a distinct endonucleolytic activity in vitro using an oligonucleotide substrate that is tethered by a short single-stranded DNA. The purified RAG1 protein alone formed a nick at the near position to the recombination signal sequence. This endonucleolytic activity was eliminated by immunoprecipitation using the RAG1-specific antibody, and required the 3'-hydroxy group. All of the RAG1 mutants that were incapable of the nick and hairpin formation in the V(D)J cleavage analysis also showed this new endonucleolytic activity. This suggests that the nicking activity that was observed might be functionally different from the nick formation in the V(D)J cleavage.

• Microbiology and Biotechnology Letters
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• v.27 no.2
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• pp.124-128
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• 1999

TK6 was able to produce NAD+ dependent cyclohexanol dehydrogenase(CDH). The production of CDH was increased rapidly at the logarithmic phase and maintained constantly after that. In order to investigate the inductive production of CDH by various substrates, the bacteria were grown in the media containing alicyclic hydrocarbons and various alcohols as a sole crabon souce. CDH was induced most actively by cyclohexanol. Cyclohexanone and cyclohexane-1,2-diol also induced remarkable amount of CDH but it was induced weakly by 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 2-propanol, and 2-methyl-1-propanol. The dehydrogenase of the bacteria grown in the media containing cyclohexanol were weakly active for various alcohols, but the dehydrogenase activity for cyclohexane-1,2-diol was twice as much as that for cyclohexanol. Activity staining on PAGE of the cell free extract of Rhodococcus sp. TK6 grown in the media containing cyclohexanol reveals at least sever isozyme bands of CDH and we nominated the four major activity bands as CDH I, II, III, and IV. CDH I was strongly induced by cyclohexanol, cyclohexane-1,2-diok, but its activity was specific to cyclohexane-1,2-diol and 1-pentanol. CDH IV was strongly induced by cyclohexanol and cyclohexane-1,2-diol, and its activity was very specific to cyclohexane-1,2-diol.

• Microbiology and Biotechnology Letters
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• v.24 no.2
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• pp.197-205
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• 1996

The $\beta$-xylosidase was purified 99- fold from the culture supernatant of Pseudo onas sp. CB-33 by ammonium sulfate precipitation, PEI precipita- tion, DEAE-Sephadex column chromatography, Sephadex G-75 gel filtration chromatography and preparative disc gel electrophoresis. Molecular weight of the enzyme was estimated to be 44,000 by SDS polyacrylamide gel electrophoresis. The enzyme has a pH optimum for activity at 7.0 and is stable over pH 6.5-9.0. The optimal temperature of the enzyme was 45$\circ$C, and its enzymatic activity was completely inactivated at 55$\circ$C for 30 min. Km value of the enzyme for p-nitrophenyl-$\beta$-D-xylopyranoside was calculated to be 4.6 mM. The effect of various reagents on the $\beta$-xylosidase activity was investigated. The enzyme activity was completely inhibited by Hg$^{2+}$, Cu$^{2+}$ and Zn$^{2+}$. The $\beta$-xylosidase was inactivated by tryptophan-specific reagent, N-bromosuccinimide and tyrosine-specific reagent, iodine. The enzyme could degrade xylo-oligosaccharides to xylose and the enzyme was competitively inhibited by xylose. The $\beta$-xylosidase and endoxylanase from Psedomonas sp. CB-33 hydrolized xylan synergically. The purified enzyme also showed $\alpha$-L-arabinofuranosidase activity.

• Korean Journal of Materials Research
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• v.10 no.12
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• pp.831-837
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• 2000

To improve the catalytic activity of platinum on polymer electrolyte fuel cell(PEFC), platinum was alloyed with cobalt and nickel at various temperature. By XRD, it was observed the crystal structure of alloy catalysts were the ordered face centered cubic(f.c.c) due to the superlattice line at $33^{\circ}$. As heat-treatment temperature was increased, the particle size of alloys also were increased and the crystalline lattice parameters were decreased. According to the results from mass activity, specific activity and Tafel slope measured by cell performance test and cyclic voltammogram, the catalyst activities of alloys are higher than that pure platinum.