• Bulletin of the Korean Chemical Society
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• 제33권9호
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• pp.3004-3008
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• 2012

Small molecule conjugated peptides were prepared by solid-phase synthesis as potential novel whitening agents, and their melanogenesis inhibitory activities were investigated. The conjugated small molecules were well-known materials as tyrosinase inhibitors, and peptides were selected from the sequences that are known to antagonize melanocortin receptor 1 (MC1R). Most of small molecules-peptide conjugates showed superior melanin inhibition activity to kojic acid and arbutin. Among these, almost all compounds have -AR- sequence. From this study, we concluded that the small molecule conjugated peptides containing -AR- sequence have melanogenesis inhibitory activities and have potential to be used as novel whitening agents.

• Journal of the Korean Physical Society
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• 제73권12호
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• pp.1908-1917
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• 2018

The binding affinity between the T-cell receptors (TCRs) and antigenic peptides mainly determines immunological recognition. It is not a trivial task that T cells identify the digital sequences of peptide amino acids by simply relying on the integrated binding affinity between TCRs and antigenic peptides. To address this problem, we examine whether the affinity-based discrimination of peptide sequences is learnable and generalizable by artificial neural networks (ANNs) that process the digital experimental amino acid sequence information of receptors and peptides. A pair of TCR and peptide sequences correspond to the input for ANNs, while the success or failure of the immunological recognition correspond to the output. The output is obtained by both theoretical model and experimental data. In either case, we confirmed that ANNs could learn the immunological recognition. We also found that a homogenized encoding of amino acid sequence was more effective for the supervised learning task.

• BMB Reports
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• 제37권4호
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• pp.429-438
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• 2004

Complementary DNAs encoding $\alpha$-amylases (Amyl I, Amyl III) and glucoamylase (GA I) were cloned from Aspergillus awamori KT-11 and their nucleotide sequences were determined. The sequence of Amyl III that was a raw starch digesting $\alpha$-amylase was found to consist of a 1,902 bp open reading frame encoding 634 amino acids. The signal peptide of the enzyme was composed of 21 amino acids. On the other hand, the sequence of Amyl I, which cannot act on raw starch, consisted of a 1,500 bp ORF encoding 499 amino acids. The signal peptide of the enzyme was composed of 21 amino acids. The sequence of GA I consisted of a 1,920 bp ORF that encoded 639 amino acids. The signal peptide was composed of 24 amino acids. The amino acid sequence of Amyl III from the N-terminus to the amino acid number 499 showed 63.3% homology with Amyl I. However, the amino acid sequence from the amino acid number 501 to C-terminus, including the raw-starch-affinity site and the TS region rich in threonine and serine, showed 66.9% homology with GA I.

• Journal of Veterinary Clinics
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• 제21권3호
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• pp.253-258
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• 2004

DNA double-strand break (DSB) is a serious treat for the cells including mutations, chromosome rearrangements, and even cell death if not repaired or misrepaired. Ku heterodimer regulatory DNA binding subunits (Ku70/Ku80) bound to double strand DNA breaks are able to interact with 470-kDa DNA-dependent protein kinase catalytic subunit (DNA-PKcs), and the interaction is essential for DNA-dependent protein kinase (DNA-PK) activity. The Ku80 mutants were designed to bind Ku70 but not DNA end binding activity and the peptides were treated in breast cancer cells for co-therapy strategy to see whether the targeted inhibition of DNA-dependent protein kinase (DNA-PK) activity sensitized breast cancer cells to ionizing irradiation or chemotherapy drug to develop a treatment of breast tumors by targeting proteins involved in damage-signaling pathway and/or DNA repair. We designed domains of Ku80 mutants, 26 residues of amino acids (HN-26) as a control peptide or 38 (HNI-38) residues of amino acids which contain domains of the membrane-translocation hydrophobic signal sequence and the nuclear localization sequence, but HNI-38 has additional twelve residues of peptide inhibitor region. We observed that the synthesized peptide (HNI-38) prevented DNA-PKcs from binding to Ku70/Ku80, resulting in inactivation of DNA-PK complex activity in breast cancer cells (MDA-465 and MDA-468). Consequently, the peptide treated cells exhibited poor to no DNA repair, and became highly sensitive to irradiation or chemotherapy drugs. The growth of breast cancer cells was also inhibited. These results demonstrate the possibility of synthetic peptide to apply breast cancer therapy to induce apoptosis of cancer cells.

• BMB Reports
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• 제31권1호
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• pp.58-63
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• 1998

In this study, a mouse monoclonal antibody (mAb) against gp41(584-618), the immunodominant epitope protein, was generated. For this purpose, BALB/c mice were immunized with double branched multiple antigenic peptides derived from the HIV-1 gp41(584-618) sequence, and antibody-secreting hybridoma were produced by fusion of mice splenocytes with SP2/0 myeloma cells. One clone producing an antigen specific mAb, termed KI-41(isotype IgG1) was identified, whose specific reactivity against gp41(584-618) could be confirmed by ELISA and Western blot analysis. Epitope mapping revealed the recognition site of the mAb KI-41 to be located around the sequence RILAVERYLKDQQLLG, which comprises the N-terminal region within the immunized gp41(584-618) peptied. Since this mAb recognizes this specific epitope within the HIV-1 gp41 without any cross-reactivity to other immunodominant regions in the HIV-2 gp35, KI-41 will provide some alternative possibilities in further applications such as the development of indirect or competitive ELISA for specific antibody detection in HIV-1 infection or for other basic researches regarding the role and function of HIV-1 gp41.

• Journal of Life Science
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• 제18권3호
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• pp.298-303
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• 2008

Using a phage peptide library approach, we have isolated a peptide ligand that binds to transferrin receptor on the surface of human melanoma cell, B16F10. The library was first screened twice by recovering internalized phages and was further screened three times by competitively eluting transferrin receptor-specific phages with human transferrin among the phages bound to the cell surface. The peptides displayed by the selected phages were fused to translocation and catalytic domain of Pseudomonas exotoxin to prepare recombinant toxins. After estimating cytotoxicity of each recombinant toxin toward B16F10 cell, seven clones were selected. Sequence analysis revealed that one of the clones displayed a peptide which had a significant sequence homology with human transferrin. The peptide was chemically synthesized and was shown to be functional in delivering cytotoxic agents into B16F10 cell via interaction with transferrin receptor.

• Korean Journal of Fisheries and Aquatic Sciences
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• 제38권1호
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• pp.6-11
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• 2005

Vasopressin (VP)-related peptide was purified from the brain extract of conger eel (Conger myriaster) by reverse-phase, ion-exchange high performance liquid chromatography (HPLC). This peptide with a molecular weight of 1,051.2 Da was determined as $H-Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Arg-Gly-NH_2$, whose Cys residues made an intramolecular disulfide bridge by the automated amino acid sequence analysis, MALDI- TOF mass spectrometry. It's sequence was confirmed by identity of the elution position with the synthetic peptide in HPLC system. As a result of homology investigation, the primary structure of this peptide was the same as that of VP-superfamily member, $[Arg^8]-vasotocin$. The synthetic peptide showed a contractile activity at a minimal effective concentration of $10^{-10}\;M$ on the intestinal smooth muscle of goldfish.

• BMB Reports
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• 제40권6호
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• pp.1090-1094
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• 2007

Melittin (ME), a linear 26-residue non-cell-selective antimicrobial peptide, displays strong lytic activity against bacterial and human red blood cells. To design ME analogue with improved cell selectivity, we synthesized a melittin diastereomer (ME-D) with D-amino acid in the leucine zipper sequence (Leu-6, Lue-13 and Ile-20). Compared to ME, ME-D exhibited the same or 2-fold higher antibacterial activity but 8-fold less hemolytic activity. Circular dichroism analysis revealed that ME-D has much less $\alpha$-helical content in $\alpha$-helical content in the presence of zwitterionic EYPC/cholesterol (10 : 1, w/w) liposomes compared to negatively charged EYPE/EYPG (7 : 3, w/w) liposomes. The blue shift of the fluorescence emission maximum of ME-D in zwitterionic EYPC/cholesterol (10 : 1, w/w) liposomes was much smaller than in negatively charged EYPE/EYPG (7 : 3, w/w) liposomes. These results suggested that the improvement in therapeutic index/cell selectivity of ME-D is correlated with its less permeability to zwitterionic membranes.

• Journal of Plant Biotechnology
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• 제49권4호
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• pp.316-324
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• 2022

Hair loss causes psychological stress due to its effect on appearance. Therefore, the global market for hair loss treatment products is rapidly growing. The present study demonstrated that ginseng berry-derived and sequence-modified peptides promoted the proliferation rate of dermal papilla (DP) cells and keratinocytes, in addition to having antioxidant properties. Moreover, the potential role of these ginseng berry peptides as TGF-β2 antagonists was confirmed through in silico computer docking. In addition to promoting the growth of ,the ginseng berry-derived peptides also promoted the proliferation of keratinocytes experimental Particularly, an unmodified ginseng berry-derived peptide (GB-1) and two peptides with sequence modifications (GB-2 and GB-3) decreased ROS generation and exhibited a protective effect on damaged HaCaT keratinocytes. Computer-aided peptide discovery was conducted to identify the potential interactions of important proteins with transforming growth factor-beta 2 (TGF-β2), a key protein that plays a crucial role in the human hair growth cycle. Our results demonstrated that MAGH, an amino acid sequence present in herbal supplements and plant-based natural compounds, can inhibit TGF-β2.

• Fisheries and Aquatic Sciences
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• 제22권10호
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• pp.22.1-22.7
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• 2019

The functional peptides from protein hydrolysates of various fishery sources have been identified such as antioxidant activity. The main intention of this study was purification and characterization of antioxidative peptide from black eelpout muscle. The antioxidative peptides were purified from black eelpout (Lycodes diapterus) muscle using different proteases. Antioxidant activity of black eelpout hydrolysates was evaluated using DPPH radical scavenging activity. Among six hydrolysates, the pepsin hydrolysate had the highest antioxidant activity compared to the other hydrolysates. Therefore, it was further purified and a peptide with seven amino acid residues of DLVKVEA (784 Da) was identified by amino acid sequence analysis. The EC₅₀ value for scavenging DPPH radicals by purified peptide was 688.77 μM. Additionally, the purified peptide exhibited protective effect against DNA damage induces by oxidation in mouse macrophages (RAW 264.7 cells). The results of this study suggest that black eelpout muscle protein hydrolysate could potentially contribute to development of bioactive peptides in basic research.