• Microbiology and Biotechnology Letters
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• v.22 no.1
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• pp.52-58
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• 1994

The induced antibiotic peptides were isolatde from the white-spotted folwer chafer, Protaetia brevitarsis by injection of E. coli suspension to the larvae of the insect. The antibacterial activity of the peptides were assayed by the plate growth ingibition method, and were purified by ion-exchange chromatography, reversed-phase HPLC, ion-exchange HPLC and SDS-PAGE etc. The peptides were estimated as 9 kDa in molecular weight and named Protaecin I and Protaecin II, respectively. Protaecin I and II have strong antibacterial activities against Gram-positivie and/or Gram-negative bacteria, and they are stable in the heat treatment and in the range of pH 2-12.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.669-671
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• 2000

Antimicrobial cationic peptides have attracted increasing research and clinical interest as a natural antibiotics due to their broad spectrum of antimicrobial activites and the rapid development of multidrug-resistant pathogenic microorganisms. In this study, first, we synthesized artificial fusion partner and cationic peptide genes (lactoferricin, magainin, protegrin-1, and indolicidin). Second, we constructed recombinant expression vectors and then transformed Pichia pastoris. Finally, expressed cationic peptides were purified and tested for their antimicrobial activites. Antimicrobial activity has been tested upon the appearance of clearing zone on the plate with the lawn of gram negative E.coli XL- I blue and garm positive Staphylococcus aureus. Protegrin-1 and Indolicidin have apparant activity of cationic peotides. This fusion technique may lead to a general and suitable tool for production of pure antimicrobial cationic peptides in Pichia pastoris.

• Microbiology and Biotechnology Letters
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• v.23 no.3
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• pp.337-345
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• 1995

Biosurfactants produced by Pseudomonas aeroginosa KK-7 were purified and their properties were studied. The bacterial surfactant was seperated into two sorts of biosufactants (Type I, 11) by silica gel column chromatograpgy. On the basis of physiochemical analysis, Type I was found to be mixture of two glycolipids with M.W. 800, and Type II was peptide with M.W. 1300. The Type 11 biosurfactant was compose of glutamic acid, proline, glycine, leucine, histidine. The crude extract was used to dertermine some properties as a surfactant. The biosurfactant had the properties as stronger emulsification agent and a stronger stabilizing agent emulsion than any other surfactants tested.

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 2003.11a
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• pp.46-46
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• 2003

Hypocholesterolemic peptide isolated from glycimin (11S protein) hydrolyzate by trypsin was purified and identified as LPYP and IAVPGEVA. To investigate the effects of phyiscal properties of side chains of the hypocholesterolemic activity, some of mutant peptides were designed and synthesized chemically. The structure related structures of each peptide were simulated and constructed and their conformations were observed by using spectropolarimeter. The hypocholesterolemic activities were monitored by assaying the inhibition of 3-hydroxy-3-methylglutaryl CoA reductase (HMG-CoA reductase) in vitro and by the determination of cholesterol content in mice serum. For LPYP derivatives, Hypocholesterolemic activity was lost when hydrophobic leucine residue at N-terminus was not so critical for maintaining hypocholesterolemic activity. For idealogical design of hypocholesterolemic peptides, the structure of HMG-CoA reductase are shown and inhibition mechanism of some peptides or inhibitors will be presented. For IAVPGEVA derivative inhibition of HMG-CoA reductase has been studied. For detail study of hypocholesterolemic activity, kinetic study of inhibition of peptides on HMG-CoA reductase and structural view of ligand binding should be investigated.

• Bulletin of Food Technology
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• v.17 no.3
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• pp.69-74
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• 2004

A soy protein hydrolysate was found to inhibit rat platelet aggregation induced by ADP, an aggregating agent. To find out its principal antiplatelet peptide(s), the soy protein hydrolysate was separated successively by gel filtration chromatography, revere-phase HPLC, and cation exchange HPLC. During the course of separation, we observed that most fractions had antiplatelet effects, which suggests that most peptides have some degree of antiplatelet effect. Following the inhibitory fractions, we purified and identified two new peptides, SSGE and DEE, by LC-electrospray ionization MS and peptide equencing. Both peptides were highly hydrophilic. The concentrations to obtain 50% inhibition ($IC_50$) of the aggregation intensity were approximately $\458muM$ and $\485muM$, respectively, for SSGE and DEE.

• 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)

• Proceedings of the Ginseng society Conference
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• 1978.09a
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• pp.75-77
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• 1978

It was found that water extract of Panax ginseng strongly inhibited adrenaline-induced lipolysis in isolated fat cells of rat epididymal adipose tissue. An antilipolytic action of the water extract was easily inactivated by treatment with pronase, suggesting that the active principle might be a protein or a peptide. Experiments were designed to purify the antilipolytic substance, or insulin-like substance, of the water extract. The water extract was dialyzed against disti'led water. The outer dialysate was subjected to DEAE-cellulose column chromatography, gelfuaration on sephadex G-50 column, avicel cellulose column chromatography and phospho-cellulose column chromatography, successively. The finally purified substance gave one spot on thin layer chromatography. The molecular weight was found to be around 1000. Experiments are now in progress to elucidate the structure of this insulin-like peptide.

• Journal of Microbiology and Biotechnology
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• v.18 no.5
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• pp.880-884
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• 2008

A strain of Streptomyces sp. (M10) antagonistic to Botrytis cinerea was isolated from orchard soil obtained from Jeju Island, Korea. An antifungal substance (CN1) was purified from the culture extracts of the strain, and then identified as valinomycin through extensive spectroscopic analyses. Valinomycin showed potent in vitro antifungal activity against Botrytis cinerea and also in vivo control efficacy against Botrytis blight development in cucumber plants. Overall, the disease control efficacy of valinomycin was similar to that of vinclozolin, a commercial fungicide. This study provides the first report on the disease control efficacy of valinomycin against Botrytis blight.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.7 no.2
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• pp.153-159
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• 2021

This article provides an efficient ¹⁸F-labeling protocol based on a rapid condensation reaction between 2-cyanobenzothiazole (CBT) and N-terminal cysteine-containing biomolecules. The ¹⁸F-labeled CBT (¹⁸F-1) was prepared by radiofluorination of the tosylated precursor 4 with 18-crown-6/K+/[¹⁸F]F- complex. Using the purified ¹⁸F-1, ¹⁸F-labeled peptide (¹⁸F-7) and protein (¹⁸F-8) could be synthesized efficiently under mild conditions. This strategy would provide a convenient approach for rapid and site-specific ¹⁸F-labeling of various peptides and proteins for in vivo imaging and biomedical applications.

• Microbiology and Biotechnology Letters
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• v.40 no.2
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• pp.92-97
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• 2012

Antimicrobial peptides (AMPs) are important components of living organisms acting against Gram-negative and Gram-positive bacterial and fungal pathogens. Cathelicidin human peptides have a variety of biological activities that can be used in clinical applications. AMPs are not produced naturally in large quantities, and chemical synthesis is also economically impractical, especially for long peptides. Therefore, as an alternative, heterologous expression of AMPs by recombinant techniques has been studied as a means to reduce production costs. E. coli is an excellent host for the expression of AMPs, as well as other recombinant proteins, because of the low cost involved and its easy manipulation. However, overexpression of AMPs in E. coli has been shown to cause difficulties resulting from the toxicity of the subsequently produced AMPs. Therefore, fusion expression was theorized to be a solution to this problem. In this study, AMPs were expressed as fused proteins with the glutathione S-transferase (GST) binding protein to protect against the toxicity of AMPs when expressed in E. coli. The LL37, and hybrid gaegurin and LL37 (GGN4(1-16)-LL37(17-32), which we designated as GL32, peptides were expressed as GST-fusion proteins in E. coli and the fusion proteins were then purified by affinity columns. The purified peptides were obtained by removal of GST and were confirmed by western blot analysis. The purified antimicrobial peptides then demonstrated antimicrobial activities against Gram-negative and Gram-positive bacterial strains.