• Journal of Environmental Science International
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• v.6 no.2
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• pp.189-194
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• 1997

Toxic peptides from hornet venom, mastoparan and mastoparan-B were synthesized us- ing the solid phase peptide synthesis method and investigated the interaction of them with phospholipid bilayer, antibacterial activity, and hemolytic activity. Both toxic peptides could induce dye release at a low concentration in neutral liposome. The binding affinity of mastoparan-B for neutral liposome was smaller than that for acidic one. Mastoparan and mastoparan-B had strong antibacterial activity for gram-positive bacteria, but weak or potent activity for gram-negative ones, respectively. Mastoparan and mastoparan-B lysed erythrocyte very little up to 5 $\mu$M.

• Journal of Environmental Science International
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• v.7 no.1
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• pp.62-66
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• 1998

Toxic Mastoparan B(MP-B) which is purified from the venom of the hornet Vespa basalis is a cationic amphlphilic tetradecapeptide. MP-B and Its Ala-substituted analogues were synthesized by solld phase method and the toxic peptide-membrane interactions were examined by circular dichroism(CD) spectra, fluorescence spectra, and leakage abilities in phospholipid membranes. In the presence of phospholipid vesicles, synthetic MP-B and its analogues formed amphiphilic -helical structures, but in the buffer soletion, those exhibited random coil conformation as measured by CD. Fluorescence spectra of MP-B and its analogues which indicated the binding affinity of peptide on phospholipid vesicles showed that the replacement of Lys at position 2 and 11 with Ala caused a remarkable effect in the blue shalt and that at position 2, in the leakage ability of the peptide.

• Journal of Environmental Science International
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• v.12 no.1
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• pp.77-80
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• 2003

The interaction of mastoparan B, a cationic tetradecapeptide amide isolated from the hornet Vespa basalis, with phospholipid bilayers was studied with synthetic mastoparan B and its analogue with Ala instead of hydrophobic 12th amino acid residue in mastoparan B. MP-B and its derivative, [12-Ala]MP-B were synthesized by the solid-phase peptide synthesis method. MP-B and its analogue, [12-Ala]MP-B adopted an unordered structure in buffer solution. In the presence of neutral and acidic liposomes, the peptides took an $\alpha$-helical structure. The two peptides interacted with neutral and acidic lipid bilayers. These results indicated that the hydrophobic face in the amphipathic $\alpha$-helix of MP-B critically affected the biological activity and helical content.

• Journal of Microbiology and Biotechnology
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• v.16 no.7
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• pp.1041-1046
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• 2006

Selenium-containing peptide (selenium peptide) was produced by autolysis of total proteins of Saccharomyces cerevisiae grown with inorganic selenium. Selenium peptide exhibited antioxidant activity as a glutathione peroxidase (GPx) mimic, and its activity was dependent on the hydrolysis methods. The GPx-like activity of the hydrolyzed selenium peptide increased 2.7-folds when digested by protease, but decreased by acid hydrolysis. During the autolysis of the yeast cell, the GPx-like activity and selenium content increased 4.3- and 2.3-folds, respectively, whereas the average molecular weight (MW) of selenium peptide decreased 70%. The GPx-like activity was dependent on the MW of selenium peptide and was the highest (220 U/mg protein) at 9,500 dalton. The maximum GPx-like activity (28,600 U/g cell) was obtained by 48 h of autolysis of the cells, which were precultured with 20 ppm of selenate. Selenium peptide showed little toxicity, compared with highly toxic inorganic selenium. These results show the potential of selenium peptide as a nontoxic antioxidant that can be produced by simple autolysis of yeast cells.

• Journal of Microbiology and Biotechnology
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• v.28 no.8
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• pp.1299-1309
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• 2018

We previously reported on lactophoricin (LPcin), a cationic ${\alpha}-helical$ antimicrobial peptide derived from bovine milk, which has antimicrobial effects on Candida albicans as well as Gram-positive and Gram-negative bacteria. In this study, we designed the LPcin-YK3 peptide, a shorter analog of LPcin, and investigated its antimicrobial activity. This peptide, consisting of 15 amino acids with + 3 net charges, was an effective antimicrobial agent against the on the Gram-positive strain, Staphylococcus aureus (MIC: $0.62{\mu}g/ml$). In addition, the hemolytic activity assay revealed that the peptide was not toxic to mouse and human erythrocytes up to $40{\mu}g/ml$. We also used circular dichroism spectroscopy to confirm that peptide in the presence of lipid has ${\alpha}-helical$ structures and later provide an overview of the relationship between each structure and antimicrobial activity. This peptide is a member of a new class of antimicrobial agents that could potentially overcome the problem of bacterial resistance caused by overuse of conventional antibiotics. Therefore, it could be used as a therapeutic or natural additive, particularly in the cosmetics industry.

• Toxicological Research
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• v.6 no.1
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• pp.109-119
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• 1990

Ro09-0198, a cyclic peptide isolated from culture filtrates of Streptoverticillium griseoverticillatum, induced lysis of erythrocytes. Ro-09-0198-induced hemolysis was temperature-dependent and the sensitivity of hemolysis differed greatly among animal species. Preincubation of the peptide with phosphatidylethanolamine reduced the hemolytic activity, whereas other phospholipids present in erythrocytes in nature had no effect. A study of the structural requirements on phosphatidylethanolamine necessary for interaction with the peptide indicates that Ro09-0198 recognizes strictly a particular chemical structure of phosphatidylethanolamine: dialkylphosphoethanolamine as well as 1-acylglycerophosphoethanolamine showed the same inhibitory effct on hemolysis induced by Ro09-0198 as diacylphosphatidyl-ethanolamine, whereas phosphoethanolamine gave no inhibitory effect. Neither phosphatidyl-N-monomethylethanolamine nor alkylphosphopropanolamine had an inhibitory effect. Proton resonances of the peptide were observed in dimethyl sulfoxide solution in the presence of 1-dodecanoyl-sn-glycerophosphoethanolamine. This peptide caused permeability increase and aggregation of liposomes containing phosphatidylethanolamine. A glycerol backbone and a primary amino group of phosphatidylethanolamine are necessary for interaction with Ro09-0198 to cause membrane damage. Ro09-0198 induced a selective permeability change on liposomes. Glucose and umbelliferyl phosphate were effluxed significantly, but sucrose was only slightly permeable and inulin could not be released. Platelet aggregation and serotonin release simultaneously induced by Ro09-0198. Addition of peptide to rat platelet, loaded with the fluorescent $Ca^{++}$ chelator quin-2, caused immediate rise in cytosolic free $Ca^{++}$ to liposomal membrane containing phosphatidylethanolamine was observed dose dependently.

• Bulletin of the Korean Chemical Society
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• v.35 no.10
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• pp.3030-3034
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• 2014

Bis-chloroethylnitrosourea (BCNU) is currently used as an anti-cancer drug for glioblastoma therapy. In this study, BCNU was loaded into the hydrophobic cores of R3V6 amphiphilic peptide micelles for efficient delivery into brain tumors. The scanning electron microscope (SEM) study showed that the BCNU-loaded R3V6 peptide micelles (R3V6-BCNU) formed spherical micelles. MTT assay showed that R3V6-BCNU more efficiently induced cell death in C6 glioblastoma cells than did BCNU. In the Annexin V assay, R3V6-BCNU more efficiently induced apoptosis than did BCNU alone. Furthermore, the results showed that R3V6 was not toxic to cells. The positive charges of the R3V6 peptide micelles may facilitate the interaction between R3V6-BCNU and the cellular membrane, resulting in an increase in cellular uptake of BCNU. In vivo evaluation with an intracranial glioblastoma rat model showed that R3V6-BCNU more effectively reduced tumor size than BCNU alone. The results suggest that R3V6 peptide micelles may be an efficient carrier of BCNU for glioblastoma therapy.

• Journal of Microbiology and Biotechnology
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• v.20 no.4
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• pp.821-827
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• 2010

Gene delivery that provides targeted delivery of therapeutic genes to the cells of a lesion enhances therapeutic efficacy and reduces toxic side effects. This process is especially important in cancer therapy when it is advantageous to avoid unwanted damage to healthy normal cells. Incorporating cancer-specific ligands that recognize receptors overexpressed on cancer cells can increase selective binding and uptake and, as a result, increase targeted transgene expression. In this study, we investigated whether a peptide capable of homing to hepatocellular carcinoma (HCC) could facilitate targeted gene delivery by cationic liposomes. This homing peptide (HBP) exhibited selective binding to a human hepatocarcinoma cell line, HepG2, at a concentration ranging from 5 to 5,000 nM. When conjugated to a cationic liposome, HBP substantially increased cellular internalization of plasmid DNA to increase the transgene expression in HepG2 cells. In addition, there was no significant enhancement in gene transfer detected for other human cell lines tested, including THLE-3, AD293, and MCF-7 cells. Therefore, we demonstrate that HBP provides targeted gene delivery to HCC by cationic liposomes.

• Archives of Pharmacal Research
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• v.28 no.7
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• pp.756-760
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• 2005

Polyene macrolide amphotericin B (AmB) is the drug of choice for the treatment of disseminated fungal infections. However, because of its pronounced side effects, the drug has limited applicability. There are few interesting reports, which state that co-administration of the drug with homo-peptide of polyaspartic acid reduces the side effects of the drug. In our present study, an approach has been made to systematically synthesize low molecular weight heteropeptides consisting of L-aspartic acid and its derivative. It was hypothesized that such heteropeptides will reduce the toxic side effects of the drug by facile hydrophobic binding between the polymer and the drug. We have employed the strategy of solid phase peptide synthesis (SPPS) to synthesize low molecular weight hetero-peptides by using L-aspartic acid and benzyl-L-aspartic acid to induce the hydrophobic binding between the peptide and the drug. In future, the proposed methodology can be employed to tailor other polypeptides substituted with benzyl groups to reduce the nephrotoxicity of AmB.

• Culinary science and hospitality research
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• v.24 no.2
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• pp.103-111
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• 2018

The objectives of the present study were to examine the antioxidant activity of autofocusing fractions from egg white protein hydrolysates and obtain higher antioxidant peptide fraction, which could be applied to the food model system. Alkaline protease hydrolysate of egg white protein exerted higher antioxidant activities than other protein hydrolysates and were fractionated on the basis of the amphoteric nature of sample peptides by preparative isoelectric focusing without toxic solvents and reagents, which is termed autofocusing. Neutral and basic fractions showed higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity than the acidic fractions. The acidic and neutral fractions showed higher hydroxyl (OH) radical scavenging activity and oxygen radical absorbance capacity (ORAC) values than the basic fractions. The acidic fractions showed higher metal chelating activity than basic fractions. Antioxidant activities of some autofocusing fractions except for ORAC showed higher compared to the crude hydrolysate. These results suggest that peptides fractions from egg white protein are effective antioxidant, and that autofocusing could be useful to increase antioxidant activity for application to food system.