• BMB Reports
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• v.28 no.6
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• pp.504-508
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• 1995

The electrophoretic patterns of plasma membrane surface proteins of normal rat liver cells and rat hepatomas were compared in 10% non-denaturing and 7-15% gradient non-denaturing gel. Chemical carcinogens, 2-Me DAB (2-methyl-4-dimethylaminoazobenzene) and DENA (diethylnitrosamine), were used to induce hepatoma in rats. One protein which disappeared in hepatoma was identified in normal rat liver by non-denaturing gel electrophoresis. Rabbit antisera were raised against this specific protein, and the protein was purified by Sephacryl S-200 column and immunoaffinity chromatography using the purified antibody. The purified protein showed two bands of molecular weights approximately 50 $kD_{\alpha}$ and 52 $kD_{\alpha}$ by SDS-polyacrylamide gel electrophoresis, which reacted specifically with the antibody. However only one band was observed in non-denaturing gel and also in isoelectric focusing with a pI value of 6.6. This study showed the existence of an unique protein on the plasma membrane surface of normal rat liver cells which disappeared in rat hepatomas induced by chemical carcinogens.

• Korean Journal of Environmental Agriculture
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• v.25 no.4
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• pp.371-381
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• 2006

New proteomic techniques have been pioneered extensively in recent years, enabling the high-throughput and systematic analyses of cellular proteins in combination with bioinformatic tools. Furthermore, the development of such novel proteomic techniques facilitates the elucidation of the functions of proteins under stress or disease conditions, resulting in the discovery of biomarkers for responses to environmental stimuli. The ultimate objective of proteomics is targeted toward the entire proteome of life, subcellular localization biochemical activities, and the regulation thereof. Comprehensive analysis strategies of proteomics can be classified into three categories: (i) protein separation via 2-dimensional gel electrophoresis (2-DE) or liquid chromatography (LC), (ii) protein identification via either Edman sequencing or mass spectrometry (MS), and (iii) proteome quantitation. Currently, MS-based proteomics techniques have shifted from qualitative proteome analysis via 2-DE or 2D-LC coupled with off-line matrix assisted laser desorption ionization (MALDI) and on-line electrospray ionization (ESI) MS, respectively, toward quantitative proteome analysis. In vitro quantitative proteomic techniques include differential gel electrophoresis with fluorescence dyes. protein-labeling tagging with isotope-coded affinity tags, and peptide-labeling tagging with isobaric tags for relative and absolute quantitation. In addition, stable isotope-labeled amino acids can be in vivo labeled into live culture cells via metabolic incorporation. MS-based proteomics techniques extend to the detection of the phosphopeptide mapping of biologically crucial proteins, which ale associated with post-translational modification. These complementary proteomic techniques contribute to our current understanding of the manner in which life responds to differing environment.

• Current Research on Agriculture and Life Sciences
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• v.31 no.1
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• pp.30-37
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• 2013

Bacillus subtilis and Bacillus amyloliquefaciens are closely related species that share a similar genomic background, and are both known to secrete large amounts of proteins directly into a medium. The extracellular proteomes of two strains of Bacillus subtilis and two strains of Bacillus amyloliquefaciens were compared by 2-D gel electrophoresis during the late exponential growth phase. The relative abundance of some minor protein spots varied among the four strains of Bacillus. Over 123 spots of extracellular proteins were visualized on the gel for B. subtilis CH 97, 68 spots for B. subtilis 3-5, 230 spots for B. amyloliquefaciens CH 51, and 60 spotsfor B. amyloliquefaciens 86-1. 2D gel electrophoresis images of the four Bacillus strains showed significantly different protein profiles. Consistent with the 2D gel electrophoretic analysis, most of the B. subtilis proteins differed from the proteases secreted by the B. amyloliquefaciensstrains. Among the proteins identified from B. subtilis, approximately 50% were cytoplasmic and 30% were canonically extracellular proteins. The secreted protein profiles for B. subtilis CH 97 and B. subtilis 3-5 were quite different, as were the profiles for B. amyloliquefaciens CH 51 and 86-1. The four proteomes also differed in the major protein composition. The B. subtilis CH 97 and B. amyloliquefaciens CH 51 proteomes both contained large amounts of secreted hydrolytic enzymes. Among the four strains, B. subtilis 3-5 secreted the least number of proteins. Therefore, even closely related bacteria in terms of genomic sequences can still have significant differences in their physiology and proteome layout.

• Journal of Microbiology and Biotechnology
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• v.1 no.2
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• pp.90-95
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• 1991

A ${\alpha}-galactosidase{\;}({\alpha}-D-galactoside$ galactohydrolase; EC 3.2.1.22) was purified from the culture filtrate of Penicillium purpurogenum by DEAE-cellulose column chromatography, gel filtration of Bio gel p-l00, and subsequent SP-Sephadex C-25 chromatography. The final preparation thus obtained showed a single band on polyacrylamide disc-gel and SDS-polyacrylamide gel electrophoresis. The molecular weight and isoelectric point were determined to be 63,000 and pH 4.0 by SDS-polyacrylamide gel electrophoresis and isoelectric focusing, respectively. The galactosidase exhibited maximum activity at pH 4.5 and $55^{\circ}C$, and was stable between pH 2 and 5, and also stable up to $40^{\circ}C$. The enzyme activity was not affected considerably by treatment with other metal compounds except mercuric chloride and silver nitrate. Copra galactomannan was finally hydrolyzed to galactose, mannose and mannobiose through the sequential actions of the purified galactosidase and mannanase from the same strain. The enzyme hydrolyzed melibiose and raffinose, but not lactose.

• Biomolecules & Therapeutics
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• v.13 no.3
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• pp.150-155
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• 2005

The ethanolic extract of chestnut (Castanea crenata S. et Z., Fagaceae) inner shell (CISE) and one of its components, ellagic acid (EA), were evaluated for their protective effects against 1, 1-diphenyl-2-picryl hydrazine (DPPH) free radical generation and hydrogen peroxide-induced oxidative DNA damage in a mammalian cell line. CISE and EA were shown to possess the free radical scavenging effect against DPPH radical generation, significantly. They were also found to strongly inhibit hydrogen peroxide-induced DNA damage from Chinese hamster lung (CHL) cell, assessed by single cell gel electrophoresis assay and 8-hydroxy -2'-deoxy guanosine (8-OH-2'dG) assay. Furthermore, topical application of CISE [$12.5\%$(w/w) cream] and ellagic acid [$1.0\%$(w/w) cream] for 14 days potently inhibited malondialdehyde (MDA) formation of mouse dorsal skin (a marker of lipid peroxidation) induced by ultraviolet B exposure. Therefore, CISE and its component, ellagic acid, may be the useful natural antioxidants by scavenging free radicals, inhibition of lipid peroxidation and protecting oxidative DNA damage when topically applied.

• Nutritional Sciences
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• v.9 no.4
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• pp.317-322
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• 2006

Soybeans are well-known as allergenic foods. Koreans consume large amounts of soybean foods, such as kochujang, which have gone through the fermentation process. To lower the allergenicity of these foods, we prepared hypo allergenic kochujang with aloe extract (AK). A sensory evaluation was conducted along with a clinical evaluation that used a double-blind, placebo-controlled food challenge (DBPCFC) test These tests were designed to evaluate the acceptability of the fermented foods. In comparison to normal kochujang (NK), AK elicited a higher sensory test score, and the rate of positive reactions in atopic dermatitis patients during the DBPCFC test was reduced. Methods of protein extraction, protein quantitation with sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), and protein identification using two-dimensional (2D) gel electrophoresis were performed for both NK and AK to compare the functional factors. We found a reduction in the levels of high molecular proteins even though the bands of the proteins had not entirely disappeared, indicating that the boiling and fermentation process changed the soybean protein patterns. The rate of the reduction of high molecular proteins was more effective in the AK. In conclusion, AK can be recognized as a food with hypoallergenic effect.

• Journal of Applied Biological Chemistry
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• v.51 no.3
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• pp.88-94
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• 2008

Three different protein extraction methods-phenol extraction, trichloroacetic acid (TCA) precipitation, and desalting/TCA precipitation-were compared to determine the optimal reproducible high resolution 2-dimensional (2-D) electrophoresis for each chungkugjang, doenjang, and kochujang samples. The soluble proteins from Chungkugjang extracted by phenol were separated with high reproducibility and resolution, and gained 1.75- to 3-fold more protein spots on 2-D gel than those from the other methods. On the contrary, the extracted proteins from doenjang and kochujang treated by desalting/TCA precipitation method showed about 1.5- to 3.3-fold more protein spots on 2-D gel. Using the established methods, the changes in the protein profiles of the fermented soy foods were monitored during the fermentation period by 2-DE. One of the major proteins in soy, $\beta$-conglycinin $\alpha$-subuint, and some proteins with unknown functions were localized on 2-D gel as the protease-resistant proteins throughout the fermentation period of doenjang. Changes in the protein profile monitored by the established methods can provide basic information on unfolding the mechanisms of the generation of biofunctional activity in the fermented soy foods.

• Journal of Microbiology
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• v.44 no.4
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• pp.369-374
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• 2006

To investigate the mechanism of salt tolerance of gram-positive moderately halophilic bacteria, two-dimensional gel electrophoresis (2-D PAGE) was employed to achieve high resolution maps of proteins of Halobacillus dabanensis $D-8^T$. Approximately 700 spots of proteins were identified from these 2-D PAGE maps. The majority of these proteins had molecular weights between 17.5 and 66 kDa, and most of them were distributed between the isoelectric points (pI) 4.0 and 5.9. Some protein spots were distributed in the more acidic region of the 2-D gel (pI <4.0). This pattern indicated that a number of proteins in the strain $D-8^T$ are acidic. To understand the adaptation mechanisms of moderately halophilic bacteria in response to sudden environmental changes, differential protein profiles of this strain were investigated by 2-D PAGE and $Imagemaster^{TM}$ 2D Platinum software after the cells were subjected to salt shock of 1 to 25% salinity for 5 and 50 min. Analysis showed 59 proteins with an altered level of expression as the result of the exposure to salt shock. Eighteen proteins had increased expression, S proteins were induced, and the expression of 33 proteins was down-regulated. Eight of the up-regulated proteins were identified using MALDI-TOF/MS and MASCOT, and were similar to proteins involved in signal transduction, proteins participating in energy metabolism pathways and proteins involved in stress.

• Applied Biological Chemistry
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• v.30 no.2
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• pp.163-168
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• 1987

A method, based upon the separation of cellular proteins by one-and two-dimensional electrophoresis was used for distinguishing butween Bradyrhizobium japonicum strains and Rhizobium fredii strains. Significant differences in protein pattern of one-dimensional SDS-PAGE vs-ere observed between Rhizobium fredii strains and Bradyrhizobium japonicum strains. The differences in six distinct main lands were observed among total 52 kinds of protein bands. Furthermore, the distribution of proteins in two groups by two-dimensional polyacrylamide gel electrophoresis was very different. The majority of visible proteins of Rhizobium fredii were acidic, whereas those of Bradyrhizobium japonicum were basic. In addition, amino acid composition was analyzed to detect the differences between two groups. No significant differences in amino acid composition were observed between Bradyrhizobium japonicum strains and Rhizobium fredii strains. The results indicate that one-and two-dimensional polyacrylamide gel electrophoresis were useful for identifying rhizobia isolates. One-dimensional SDS-PAGE of rhizobia proteins provided a rapid method for screening a large number of isolates, whereas two-dimensional electrophoresis was more of resolution and easiness for analyzing protein spots.

• Journal of Microbiology and Biotechnology
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• v.1 no.2
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• pp.102-110
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• 1991

Alkalophilic Bacillus sp. YJ-451, which was isolated from soil at several area in Korea, produced a novel type of bacteriolytic enzyme (cell wall peptidoglycan hydrolase) extracellulary. The cell wall hydrolytic activity was identified as a clear zone on sodium dodecyl sulfate polyacrylamide gel electrophoresis containing 0.2% (w/v) cell wall of Bacillus sp. as substrate. This enzyme was successively purified 66 fold with 3.2% yield in culture broth by ammonium sulfate precipitation, CM-cellulose column chromatography, and gel filtration, followed by hydroxylapatite column chromatography. The molecular weight of the purified enzyme was estimated to be 27,000 by sodium dodecyl sulfate polyacrylamide gel electrophoresis and gel filtration column chromatography. The optimum pH and temperature for the activity of the enzyme were pH 10.0 and $50^{\circ}C$, respectively. The enzyme was stable between pH 5.0 and 10.0 and up to $40^{\circ}C$. Among the microorganisms used in this experiment the enzyme was active against most of gram negative strains and the genus Bacillus such as B. megaterium, B. licheniformis, B. circulans, B. pumilus, B. macerans, B. polymyxa. The release of dinitrophenylglutamic acid but not reducing group from cell wall peptidoglycan digested by the enzyme suggested that the enzyme is a kind of peptidase which hydrolyzes the peptide bond at the amino group of D-glutamic acid in the peptidoglycan.