• Korean Journal of Pharmacognosy
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• v.38 no.4
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• pp.372-375
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• 2007

Reactive oxygen species(ROS) or free radicals are produced in the pathogenesis of human diseases including atherosclerosis, diabetes, cancer, and aging. Antioxidants are associated with the prevention of ROS-induced tissue and cellular damage in the various diseases. This study investigated the antioxidative activities of the methanol extract of Alisma plantagoaquatica var. orientale and its main component under conditions of radical generation using allophycocyanin and ferric-thiocyanate assay. Alisol B 23-acetate as a main component was isolated from the methanol extract of Alisma plantago-aquatica var. orientale. In results, the extract of Alisma plantago-aquatica var. orientale showed inhibitory activity on AAPH [2,2'-azobis(2-amidinopropane)dihydrochloride]-induced protein oxidation. Also, the extract of Alisma plantago-aquatica var. orientale and alisol B 23-acetate inhibited lipid peroxidation. These results indicate that Alisma plantago-aquatica var. orientale and alisol B 23-acetate show promise as therapeutic agents for various damages involving free radical reactions.

• Molecules and Cells
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• v.40 no.9
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• pp.632-642
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• 2017

The DevSR (DosSR) two-component system, which is a major regulatory system involved in oxygen sensing in mycobacteria, plays an important role in hypoxic induction of many genes in mycobacteria. We demonstrated that overexpression of the kinase domain of Mycobacterium tuberculosis (Mtb) PknB inhibited transcriptional activity of the DevR response regulator in Mycobacterium smegmatis and that this inhibitory effect was exerted through phosphorylation of DevR on Thr180 within its DNA-binding domain. Moreover, the purified kinase domain of Mtb PknB significantly phosphorylated RegX3, NarL, KdpE, TrcR, DosR, and MtrA response regulators of Mtb that contain the Thr residues corresponding to Thr180 of DevR in their DNA-binding domains, implying that transcriptional activities of these response regulators might also be inhibited when the kinase domain of PknB is overexpressed.

• Journal of the Korean Chemical Society
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• v.15 no.1
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• pp.37-44
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• 1971

The reaction of amino acids and the reactive hydroxyl radical generated by $Ti^{3+}-H_2O_2$ system was studied using fast flow techniques coupled with ESR. Upon adding methionine to the 0.2M $H_2O_2$ solution (0.05M methionine after addition) and mixing with 0.01M $TiCl_3$, the low field component of the two incompletely resolved peaks, in the spectrum of $Ti^{3+}-H_2O_2$ system alone, vanished completely whereas the high field component remained almost constant and superimposed on the secondary spectrum of the methionine free radical. Similar results were obtained for other amino acids and proteins. The results strongly demonstrate that the $T^{3+}-H_2O_2$ flow system generates two different radical species, only one of which, giving rise to the low field component, is alone responsible for abstracting hydrogen atoms from substrate molecules. The effects of HCl, $H_2SO_4$ and NaOH on the system were also studied with widely varying results.

• Journal of Microbiology and Biotechnology
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• v.17 no.2
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• pp.244-252
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• 2007

Escherichia coli has a PhoR-PhoB two-component regulatory system to detect and respond to the changes of environmental phosphate concentration. For the E. coli W3110 strain growing under phosphate-limiting condition, the changes of global gene expression levels were investigated by using DNA microarray analysis. The expression levels of some genes that are involved in phosphate metabolism were increased as phosphate became limited, whereas those of the genes involved in ribosomal protein or amino acid metabolism were decreased, owing to the stationary phase response. The upregulated genes could be divided into temporarily and permanently inducible genes by phosphate starvation. At the peak point showing the highest expression levels of the phoB and phoR genes under phosphate-limiting condition, the phoB- and/or phoR-dependent regulatory mechanisms were investigated in detail by comparing the gene expression levels among the wild-type and phoB and/or phoR mutant strains. Overall, the phoB mutation was epistatic over the phoR mutation. It was found that PhoBR and PhoB were responsible for the upregulation of the phosphonate or glycerol phosphate metabolism and high-affinity phosphate transport system, respectively. These results show the complex regulation by the PhoR-PhoB two-component regulatory system in E. coli.

• Journal of Food Hygiene and Safety
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• v.18 no.3
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• pp.146-152
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• 2003

Pyruvate dehydrogenase phosphatase (PDP) is a mitochondrial protein serine/threonine phosphatase that catalyzes the dephosphorylation and concomitant reactivation of the pyruvate dehydrogenase component of the pyruvate dehydrogenase complex (PDC). PDP consists of a catalytic subunit (PDPc, Mr 52,600) and regulatory subunit (PDPr, Mr 95,600). In the presence of $Ca^{2+}$, PDPc binds to the dihydrolipoamide acetyltransferase (E2) component of the pyruvate dehydrogenase complex in proximity to its substrate, the phosphorylated E1 component, thereby increasing the rate of dephosphorylation. PDPc possesses and intrinsic $Ca^{2+}$ binding site and a second $Ca^{2+}$ site is generated in the presence of E2. Using the unique interaction, highly pure PDPc was produced by the GSH-Sepharose-GST-L2 matrix with a specific activity of approx. 1000 U/mg and a yield of about 80%.

• Journal of Photoscience
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• v.9 no.2
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• pp.323-325
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• 2002

Bacillus Anthracis is the causative agent of anthrax. The major virulence factors are a poly-D glutamic acid capsule and three-protein component exotoxin, which is collectively known as anthrax toxin, protective antigen (PA, 83 kDa), lethal factor (LF, 90 kDa), and edema factor (EF, 89 kDa). These three proteins individually have no known toxic activities, but in combination with PA form two toxins (lethal toxin and edema toxin), causing different pathogenic responses in animals and cultured cells. However, it remains to be elucidated for pathogenic mechanism of anthrax toxin. In this study, we constructed toxin component in bacterial overexpression system and purified the native toxin from Bacillus anthracis delta sterne F32 using FPLC system. Recombinant toxin showed high homogeneity and rapid purification processes. Also, this recombinant toxin was comparable to B. anthracis native toxin in terms of cytotoxic effects on cultured cell lines.

• Korean Journal of Pharmacognosy
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• v.15 no.2
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• pp.61-73
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• 1984

To investigate antitumor component of Lyophyllum decastes, the aqueous extract of its shake-cultured mycelia was subjected to antitumor test against sarcoma 180 cells implanted in ICR mice. The extract showed an inhibition ratio of 65.4% and was found to consist of a polysaccharide moiety and a protein moiety. After purification with DEAE-Sephadex A-50 ion exchange chromatography, Fraction D showed the highest inhibition ratio of 75.7%. The antitumor constituent was examined for immunoaccelerating activity and was found to increase macrophage accumulation in the peritoneal cavity and plaque forming cells of the spleen cells. It was named lyophyllan after the genus name.

• Korean Journal of Microbiology
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• v.49 no.1
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• pp.95-98
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• 2013

Following construction of expression vectors in Escherichia coli, a new procedure involving two-step column purifications with a Fast Performance Liquid Chromatography System was developed for purification of the oxygenase component of alkylphenol hydroxylase of Pseudomonas alkylphenolia. From 50 g wet cake of recombinant E. coli BL21(DE3)(pJJPMO2) cells, 110 mg of pure protein in a heterodimeric form containing a stoichiometric amount of iron were obtained and it exhibited a specific activity of 147 nmole/min/mg.

• Food Science and Biotechnology
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• v.18 no.4
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• pp.910-916
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• 2009

Present work was focused on the influence of methylcellulose (MC) on steady rheology of wheat gliadin solution and the properties of glycerol plasticized gliadin films. The presence of MC below 0.99 wt% improved viscosity and flow activation energy of the 10 wt% gliadin solution significantly. In the casting films containing 0.2 g glycerol/g dry protein, the MC component aggregated in the gliadin matrix. The blend films containing less than 7.7 wt% MC exhibited higher Young's modulus (E) and tensile strength (${\sigma}_b$) and lower elongation at break (${\epsilon}_b$) in comparison with the pure gliadin film, which was related to the intermolecular interaction between MC and gliadins, the brittle fracture of the aggregated MC component, and the increase in glass transition temperature ($T_g$) of the gliadin phase. Increasing MC content led to a slight increase in water vapor permeability (WVP) without significant influence on the moisture absorption (MA).

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.10
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• pp.4873-4878
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• 2012

Apoptosis is programmed cell death which is essential for development and survival of living organisms. It is a sequentially regulated suicidal programme where cells activate certain enzymes which dissolute their own nuclear component and various protein component of nucleus and cytoplasm. Disturbance of this regulatory pathway may lead to various diseases like autoimmune diseases, neurodegenerative diseases and cancers. The potential mechanisms of apoptosis and its role in cancer are discussed. The ability of apoptosis to modulate the life or death of a cell is also recognized for its immense therapeutic potential. Understanding the mechanisms from this review will give us better insight to the pathogenesis of various diseases including cancer and will open new horizons to therapeutic approaches.