• Korean Journal of Food Science and Technology
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• 제30권1호
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• pp.82-89
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• 1998

This study was performed to elucidate the purification and characterization of pretease from saewoo-jeot, a Korean traditional salt-fermented shrimp product. The protease in saewoo-jeot (Acetes japonicus) were extracted, desalted through electrodialysis and purified by ammonium sulfate fractionation, Sephadex G-100 gel filtration and DEAE-cellulose column chromatography. Purified enzyme had specific activity of 8.4 unit/mg, yield of 14% and purification fold of 9.8. Purified enzyme was confirmed as single band protein by polyacrylamide gel electrophresis and the molecular weight was estimated to be about 24 kDa. The optimal pH and temperature for the enzyme activity were 8.0 and $40^{\circ}C$, respectively. The range of its stability to the pH and temperature were 7.0 to 10.0 and $30^{\circ}C\;to\;60^{\circ}C$, respectively. The activity of enzyme to synthetic substrate showed BAPNA and TAME. The enzyme was activated significantly by manganese ions, while inhibited by STI, TLCK. metals $(K^+,\;Li^+,\;Na^+,\;Ca^{++},\;Co^{++},\;Cu^{++},\;Mg^{++},\;Ba^{++},\;Hg^{++},\;Zn^{++},\;Fe^{+++})$. The Km value of the enzyme was $5.1{\times}10^{-7}\;M$ to hammersten casein. It's suggested that purified protease from saewoo-jeot seemed to be trypsin-like enzyme.

• The Plant Pathology Journal
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• 제22권3호
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• pp.260-264
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• 2006

Talaromyces flavus mediates the transmission of Apple stem grooving virus (ASGV) to several host plants. The ASGV-F carried by T.flavus was partially purified from the fungus. Based on sequence analysis and homology searches, this is closely related to other ASGV strains isolated from host plants. The partially purified viral coat protein (CP) was separated on a 12% SDS-polyacrylamide gel and analyzed by Western blotting with an ASGV anti-serum. A single band at 28 kDa reacted with the ASGV anti-serum. The deduced amino acid sequence of the ORF-l showed conserved domains, including an NTP-binding helicase motif, GFAGSGKT. The amino acid sequences of the helicase and CP showed strong homology to other ASGV strains (98%). All ASGV isolated from plants and fungi had salt bridges composed of the CP and the GFAGSGKT motif of the helicase, which are commonly conserved in plant viruses. These results suggest that ASGV-F is one of ASGV strains isolated from T.flavus based on sequence similarity as well as the serological analysis of CP.

• Culinary science and hospitality research
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• 제11권2호
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• pp.91-109
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• 2005

The purpose of this study was to investigate the changes of vitamin C and lactic acid bacteria count in Dongchimi used different kinds of water (distilled water, purified water, Cho Jung Carbonated Natural water). Dongchimi used different kinds of water was fermented at $10^{\circ}C$ for 46 days. The changes of pH on Dongchimi used different kinds of water decreased in all samples during fermentation period, and then showed a slow decrease after 12 days of fermentation. The total acidity of Dongchimi used Cho Jung Carbonated Natural water arrived slowly at best tasting condition(0.3~0.4 point) compared with other conditions. The changes of salt content were ranked high one by one , Cho Jung Carbonated Natural water>purified water>distilled water during fermentation period. At early stage of fermentation, the changes of turbidity of Dongchimi used Cho Jung Carbonated Natural water showed highly as compared with other test conditions for 12 days of fermentation. Vitamin C content was measured high in Dongchimi used Cho Jung Carbonated Natural water during the fermentation period. Because calcium content was high in carbonated natural water, carbonated natural water had the highest calcium content during the fermentation period. The changes of lactic acid bacteria count showed the highest price at all experimental groups in 15 days of fermentation, but those of Dongchimi used Cho Jung Carbonated Natural water showed the highest price in 19 days of fermentation.

• Journal of the Korean Chemical Society
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• 제43권3호
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• pp.307-314
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• 1999

Ml RNA, the RNA component of RNase P from Escherichia coli, is produced by 3' processing of pre-Ml RNA, a major primary transcript of the rnpB gene. The enzyme fraction containing the processing activity was partially purified and characterized. Since exposure of the active fraction to the high salt condition results in the inactivation of the processing activity, the processing enzyme seems to be an enzyme complex composed of multiple enzymes. The enzyme fraction loses the processing activity when treated with the chemical nuclease lead(II) ion, but regains its activity by the addition of RNA isolated from the enzyme fraction itself, suggesting that an RNA molecule(s) may be essential for the processing activity. Analysis of cleavage sites produced by the partially purified enzyme fraction also implies that the 3' processing occurs by multiple enzymes and at least in two distinct pathways.

• Korean Journal of Food Science and Technology
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• 제28권3호
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• pp.538-544
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• 1996

A highly viscous biopolymer from alkali-tolerant Bacillus sp. was purified and its rheological properties were studied. 1% (w/v) solution of purified biopolymer showed pseudoplastic fluid behavior with the yield stress similar to those of xanthan and guar gum, and its consistency index was exponentially dependent on concentration and temperature. The concentration dependency of consistency index exhibited two rectilinear plots with different slopes at 1% concentration and pseudoplastic property increased with the increase of biopolymer concentration. The biopolymer solution exhibited a low temperature dependency and the activation energy of flow was 1.16 kacl/g mol. The apparent viscosity was very dependent on the change of pH and the addition of salt. However, no organic solvent effects were observed effects of viscosity synergism with the addition of viscosifier were not observed.

• BMB Reports
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• 제29권6호
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• pp.519-524
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• 1996

Peptidylprolyl cis-trans isomerase (PPlase) catalyzes the cis-trans isomerization of prolyl peptide and facilitates the folding of cellular proteins and peptides. PPlase consists of two distinct immunophilins, each specifically binding to the immunosupressive drug cyclosporin A (CsA) or FK506, respectively. A PPlase was isolated and partially purified from porcine spleen. The molecular weight of porcine spleen PPlase was determined to be ~14,000 on the basis of SDS-PAGE. The purified enzyme was strongly inhibited by FK506, but not by CsA. The inhibition constant and the true concentration of enzyme preparations were determined by active site titration using the tight binding inhibitor FK506: $K_{i}=18.7$ nM and $E_{t}=172$ nM. The equilibrium ratio of conformer. [cis]/[trans], of prolyl peptide substrates (N-Suc-Ala-Xaa-Pro-Phe-p-NA) in anhydrous trifluoroethanol/LiCl solvent system varied from 0.24 to 0.85 depending on the nature of Xaa. Overall. in this solvent-salt system, the populations of the cis conformer of substrates in equilibrium are higher than in an aqueous solution so that the substantial error caused by high background absorption can be reduced. The reactivities of porcine spleen PPlase are shown to be highly sensitive to changes in the structure of substrates. Thus, $k_{cat}/K_m$ value for the most reactive substrate (Xaa Leu) is $4.007+10^{6}M^{1}s^{1}$ and, is 2,636 fold higher than that for the least reactive peptide substrate tested, Xaa=Glu.

• The Journal of Natural Sciences
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• 제14권2호
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• pp.67-82
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• 2004

A thiol-specific antioxidant protein (TSA or TPx) was purified from Halophilic archeabacteria Halococcus agglomeratus, by DEAE-Cellulose, Phnyl, sepharose, Sephadex G-75, Sephacryl S-100, Sephacryl S-200, and Q-Wepharose FF. This protein exhibited the preventeive effect against the inactivation of glutamine synthehase (GS) activity was support by a thiol-reducing equicalent such as dithiothreitol. TPx activity was maximal at NaCl concentration above 500mM. The molecular mass of the protein was determinated to be 22-kDa by SDS-PAGE. The TPx purified from Halococcus agglomeratus seems to be similar to other TPx family, except for the salt requirement for the maximal antioxidant activity.

• Korean Journal of Food Science and Technology
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• 제35권2호
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• pp.260-265
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• 2003

Transglutaminase (TG) was prepared from Streptomyces mobaraensis to improve texture and self-life of food. In preliminary experiments, texture of the dough was not improved due to the interference in microbial TG reaction by proteases present in the crude enzyme. Among the cation exchange resins tested for the removal of proteases, MonoPlus S 100 was the most efficient. Further purification steps with a quaternary ammonia salt resin and gel permeation chromatography effectively removed proteases from crude enzyme. Molecular weight of purified enzyme was about 38,000 on SDS-polyacrylamide gel electrophoresis. Farinograph data showed the addition of purified enzyme to wheat flour gave higher stability and lower weakness values those that of crude enzyme.

• Journal of Microbiology and Biotechnology
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• 제31권8호
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• pp.1144-1153
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• 2021

A released exopolysaccharide (rEPS)-producing strain (LM187) with good acid resistance, bile salt resistance, and cholesterol-lowering properties was isolated from Sichuan paocai and identified as Leuconostoc mesenteroides subsp. mesenteroides. The purified rEPS, designated as rEPS414, had a uniform molecular weight of 7.757 × 10⁵ Da. Analysis of the monosaccharide composition revealed that the molecule was mainly composed of glucose. The Fourier transform-infrared spectrum showed that rEPS414 contained both α-type and β-type glycosidic bonds. ¹H and ¹³C nuclear magnetic resonance spectra analysis showed that the purified rEPS contained arabinose, galactose, and rhamnose, but less uronic acid. Scanning electron microscopy demonstrated that the exopolysaccharide displayed a large number of scattered, fluffy, porous cellular network flake structures. In addition, rEPS414 exhibited strong in vitro antioxidant activity. These results showed that strain LM187 and its rEPS are promising probiotics with broad prospects in industry.

• Korean Journal of Fisheries and Aquatic Sciences
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• 제54권6호
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• pp.927-937
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• 2021

This study was performed to screen the antimicrobial activities of the extract from the Pacific oyster Crassostrea gigas against skin pathogens and to purify the relevant antibacterial peptide. The acidified extract showed potent antibacterial activities against gram-positive and gram-negative bacteria but showed no activity against Candida albicans and no significant cell toxicity. Among acne-causing pathogens, the acidified extract showed potent antibacterial activity only against Staphylococcus aureus, and its antibacterial activity was completely abolished by treatment with trypsin or chymotrypsin, and was inhibited by salt treatment. The acidified extract showed strong DNA-binding ability but did not show bacterial membrane permeabilizing ability. Based on antimicrobial activity screening and cytotoxic effects, a novel antibacterial peptide was purified from the acidified gill extract using solid-phase extraction, cation-exchange, and reversed-phase HPLC. The resulting peptide had a molecular weight of 4800.8 Da and showed partial sequence homology with the carbonic anhydrase 4 (CA4) protein in the hard-shelled mussel. Overall, we purified a novel antibacterial peptide, named cgCAFLP, which is related to carbonic anhydrase 4 (CA4) protein, against skin pathogens. Our results suggest that the Pacific oyster extract could be used as an additive to control some acne-related skin pathogens (S. aureus).