• Animal cells and systems
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• 제12권1호
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• pp.35-39
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• 2008

Menadione induced cell death in cultured C2 myoblasts. By screening synthetic peptide libraries composed of random sequence of hexapeptides, we identified the hexa-peptides pool of(Ala/Ile)-(Ile/Met)-Val-Ile-Asp-(Met/Ser)-$NH_2$ that protected the myoblasts against menadioneinduced cell death. Pre-incubation with the hexapeptide pool reduced the number of cells detached from culture dish substrate and increased the ratio of relative viability against menadione. In addition, the peptides strongly increased the expression of Bcl-2, an anti-apoptotic protein. These results suggest that the hexapeptides might enhance the resistance to cell death against menadione by increasing the expression of Bcl-2.

• The Plant Pathology Journal
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• 제33권1호
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• pp.87-94
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• 2017

Citrus canker disease decreases the fruit quality and yield significantly, furthermore, emerging of streptomycin-resistant pathogens threatens the citrus industry seriously because of a lack of proper control agents. Small synthetic antimicrobial peptides (AMPs) could be a promising alternative. Fourteen hexapeptides were selected by using positional scanning of synthetic peptide combinatorial libraries. Each hexapeptide showed different antimicrobial spectrum against Bacillus, Pseudomonas, Xanthomonas, and Candida species. Intriguingly, BHC10 showed bactericidal activity exclusively on Xanthomonas citri subsp. citri (Xcc), while BHC7 was none-active exclusively against two Pseudomonas spp. at concentration of $100{\mu}g/ml$ suggesting potential selectivity constrained in hexapeptide frame. Three hexapeptides, BHC02, 06 and 11, showed bactericidal activities against various Xcc strains at concentration of $10{\mu}g/ml$. When they were co-infiltrated with pathogens into citrus leaves the disease progress was suppressed significantly. Further study would be needed to confirm the actual disease control capacity of the selected hexapeptides.

• Journal of Microbiology and Biotechnology
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• 제19권8호
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• pp.792-802
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• 2009

Antimicrobial peptides (AMPs) are considered to be a promising alternative to conventional antibiotics for future generations. We identified four novel hexapeptides with antimicrobial activity: KCM11 (TWWRWW-$NH_2$), KCM12 (KWRWlW-$NH_2$), KCM21 (KWWWRW-$NH_2$), and KRS22 (WRWFIH-$NH_2$), through positional scanning of a synthetic peptide combinatorial library (PS-SCL). The ability of these peptides to inhibit the growth of a variety of bacteria and unicellular fungi was evaluated. KCM11 and KRS22 preferentially inhibited the normal growth of fungal strains, whereas KCM12 and KCM21 were more active against bacterial strains. Bactericidal activity was addressed in a clear zone assay against phytopathogenic bacteria, including Pectobacterium spp., Xanthomonas spp., Pseudomonas spp., etc. KCM21 showed the highest activity and was effective against a wide range of target organisms. Application of KCM21 with inoculation of Pectobacterium carotovorum subsp. carotovorum on detached cabbage leaves resulted in an immune phenotype or a significant reduction in symptom development, depending on the peptide concentration. Cytotoxicity of the four hexapeptides was evaluated in mouse and human epithelial cell lines using an MTT test. The results revealed a lack of cytotoxic effects.

• Mass Spectrometry Letters
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• 제5권2호
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• pp.52-56
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• 2014

Glycated hemoglobin (HbA1c) is used as an index of mean glycemia over prolonged periods. This study describes an optimization of enzyme digestion conditions for quantification of non-glycated hemoglobin (HbA0) and HbA1c as diagnostic markers of diabetes mellitus. Both HbA0 and HbA1c were quantitatively determined followed by enzyme digestion using isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) with synthesized N-terminal hexapeptides as standards and synthesized isotope labeled hexapeptides as internal standards. Prior to quantification, each peptide was additionally quantified by amino acid composition analysis using ID-LC-MS/MS via acid hydrolysis. Each parameter was considered strictly as a means to improve digestion efficiency and repeatability. Digestion of hemoglobin was optimized when using 100 mM ammonium acetate (pH 4.2) and a Glu-C-to-HbA1c ratio of 1:50 at $37^{\circ}C$ for 20 h. Quantification was satisfactorily reproducible with a 2.6% relative standard deviation. These conditions were recommended for a primary reference method of HbA1c quantification and for the certification of HbA1c reference material.

• Bulletin of the Korean Chemical Society
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• 제28권9호
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• pp.1535-1538
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• 2007

The work presented in this paper represents a study of the rate and extent of transdermal penetration of three synthetic hexapeptides consisting only of glycine (Gly) and phenylalanine (Phe) as the constituent amino acids and they include Phe-Gly-Gly-Gly-Gly-Gly (Pep-1), Phe-Phe-Gly-Gly-Gly-Gly (Pep-2), and Phe-Phe-Phe- Gly-Gly-Gly (Pep-3). The present study demonstrated the extent to which the peptides having a high metabolic stability were transdermally transported from the various vehicles. The results of this study appear to indicate that minor differences in the lipophilicity of the synthetic hexapeptides have a slight influence on the rate and extent of transport. In the presence of terpene permeation enhancers, together with ethanol (i.e., menthone/ EtOH, carveol/EtOH or cineole/EtOH), the peptides were more rapidly penetrated through the skin and among the terpenes tested, cineole was the most effective for all three peptides. The maximum enhancement ratio of approximately 2 was achieved by cineole in 50% ethanol solution.

• 대한화학회지
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• 제36권4호
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• pp.523-535
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• 1992

ECEPP/2 및 MM2 방법을 이용하여 고리형 헥사펩티드의 형태 및 알칼리 금속 양이온과의 착물형성 그리고 DPH에 의한 양이온 전달방해를 이론적으로 살펴보았다. 착물을 형성하지 않은 고리형 펩티드에 대하여 여러 가지 안정한 형태가 얻어졌으며, 대부분의 아미드 수소원자는 카르보닐 산소와 분자내 수소결합을 이루고 있어 조밀한 구조를 나타내었다. 펩티드와 Na$^+$ 이온 및 DPH간의 착물형성에너지는 각각 -60kcal/mol 및 -18kcal/mol이었다. 그러나 헥사펩티드의 국부최소에너지 구조들에는 금속 양이온을 결합할 수 있는 공동이 존재하지 않았고 공동이 존재하는 헥사펩티드의 에너지는 본 연구의 최저에너지 구조보다 10kcal/mol 정도 높은 에너지를 주었으며, 이러한 에너지 차이와 금속 양이온의 탈수 과정을 고려하면 DPH에 의한 양이온 전달방해를 설명할 수 있었다. 또한 DPH와 결합하는데 있어서의 가장 중요한 아미노산 잔기는 글리신이었으며 이를 사코신(N-메틸 글리신) 으로 치환할 때 양이온 전달이 저해되는 실험적 사실을 설명할 수 있었다.

• 한국자원식물학회지
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• 제5권2호
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• pp.73-84
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• 1992

Many types of compounds have been isolated from higher plants till now, that is, alkaloids, terpenes, lignans, steroids and so on. One of them, named as RA series Cyclic hexapeptides isolated from Rubia akane and R. cordijofia also have strong antineoplastic activity against various types of tumors. Till now 10 kinds ofRA series compounds were isolated and named as RA - I, II, III, IV, V, VI, VII, VIII, IX and X. Moreover,monogl-ucoside of RA - V newly Isolated from same plant. Many kinds of derivatives including natural RAcompounds were tested for QSAR, and one of them, RA - VII was screened up as a most suitable substance asan antitumor agent. RA - VII(=RA-700) has strong cytotoxic activity against KB cells, P388 Iymphocyticleukemia and MM2 mammary carcinoma cells. RA - VII has been under investigation for Phase I clinical trials.

• 한국자원식물학회지
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• 제1권1호
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• pp.8-22
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• 1988

Vincristine and vinblastine isolated from Vinco spp. , and podophyllotoxine derivatives isolated from Podophyllum spp. are usefulas anticancerous components obtaned from higher plants. More thanten antineoplastic compounds are now following them as anticancerousagents from higher plants. In my laboratory, Sarcoma 180A has beenused as the first screening test. By this method, I have found outsome kinds of antineoplastic constituents from active plants extracts .For instance, bisaborane type compounds were isolated from Curcumaxanthorrhiza, one of Indonesian plants; a morphinane type compoundfromCocculus trilobus; cyclic hexapeptides from Rubia akane and R.cordiorta. Seven components having antineoplastic actirity wereisolated from Rubia spp. except. R. tinctoria. Their structures wereelucidated except RA-Vl by chemical reaction and variovs instrumentalanalysis as shown in Fig. Among of them, RA-Vll showed strong activityagainst P388 Lymphocytic leukemia, L2O, B16 melanoma, Lewis lungcarcinoma, colon 38 and Ehrlich carcinoma. RA-V revealed excellentactivity against MM2 mammary carcinoma. The· value of acute LD5O ofRA-ViI were 10. Omg/kg( iP) and 16.5mg/kg( po ) respectiveIy . Therapruticratio was 400, compared with 10 of mitomycin C. QSAR was also appliedto these compounds by elongation of ether and ester side chains atR'. Mechanism of action of RA-Vll was also investigated and wasassumed to be inhibition of protein biosynthesis .

• 한국자원식물학회지
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• 제6권1호
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• pp.13-23
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• 1993

To data, many types of compounds having antineoplastic activity have been isolated from higher plants, that is, alkalodids, terpenes, lignans, steroids and so on. Some of ther were isolated from Indonesian plants, Curcuma xanthorrhiza and Eurycoma longifolia. Bisaborane type compounds were compounds were isolated as antimeoplastic compounds againest Sarcoma 180A from C. xanthorrhiza, and quassinoids and euryrene type triterpenes from triterpenes from El longifolia. Casearines, a kind of diterpene, had been isolated as cytotxic components from Casearia sylvestris distributed in South America. RA series Cyclic hexapeptides isolated from Rubia akane and R. cordifolia also have strong antineoplastic activity against various types of tumors. Till now, 16 kinds of RA series compounds were isolated and named as RA-I~XVI. Moreover, monoglucoside of RA-V newly isolated from same plant. Many kinds of derivatives including natural RA compounds were tested for QSAR, and one of them, RA-VII was screened up as a most suitable substance as an antitumor agent. RA-VII(=RA 700) has strong cytotoxic activity against KB cells, P388 lymphocytic leukemia and MM2 mammary carcinoma cells. In some solution, three conformers of RA-VII were observed by NMR. It was discussed the relationship between conformation and activity. Total synthesis was already completed, but there is left room for improvement. Phase I clinical trials for RA-VII has been finished, then Phase II trials will be started before long.

• The Plant Pathology Journal
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• 제30권3호
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• pp.245-253
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• 2014

Antimicrobial peptides (AMPs) are small but effective cationic peptides with variable length. In previous study, four hexapeptides were identified that showed antimicrobial activities against various phytopathogenic bacteria. KCM21, the most effective antimicrobial peptide, was selected for further analysis to understand its modes of action by monitoring inhibitory effects of various cations, time-dependent antimicrobial kinetics, and observing cell disruption by electron microscopy. The effects of KCM21 on Gram-negative strain, Pseudomonas syringae pv. tomato DC3000 and Gram-positive strain, Clavibacter michiganensis subsp. michiganensis were compared. Treatment with divalent cations such as $Ca^{2+}$ and $Mg^{2+}$ inhibited the bactericidal activities of KCM21 significantly against P. syringae pv. tomato DC3000. The bactericidal kinetic study showed that KCM21 killed both bacteria rapidly and the process was faster against C. michiganensis subsp. michiganensis. The electron microscopic analysis revealed that KCM21 induced the formation of micelles and blebs on the surface of P. syringae pv. tomato DC3000 cells, while it caused cell rupture against C. michiganensis subsp. michiganensis cells. The outer membrane alteration and higher sensitivity to $Ca^{2+}$ suggest that KCM21 interact with the outer membrane of P. syringae pv. tomato DC3000 cells during the process of killing, but not with C. michiganensis subsp. michiganensis cells that lack outer membrane. Considering that both strains had similar sensitivity to KCM21 in LB medium, outer membrane could not be the main target of KCM21, instead common compartments such as cytoplasmic membrane or internal macromolecules might be a possible target(s) of KCM21.