• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.218-223
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• 1998

Casein was hydrolyzed by alcalase to produce iron binding peptide (IBP). IBP was effectively separated from casein hydrolysates by immobilized $Fe^{3+}$ affinity chromatography and further purified by reverse phase chromatography. $25,\;50\;and\;100\;{\mu}g/mL$ of IBP solubilized $4.2,\;5.7\;and\;7.1\;{\mu}g$ of ferric at duodenum condition $(pH\;6,\;37^{\circ}C)$, respectively. According to the result of MALDI analysis, molecular weight of IBP was determined to 2,175 dalton. IBP was mainly composed of proline (24.5 mol%), lysine (15.7 mol%), and glutamine or glutamic acid (14.9 mol%) and its N-terminal sequence was Met-Ala-Pro-Lys-His. According to the information obtained from molecular weight, amino acids composition and N-terminal sequence of IBP, it was evident that IBP was from f102-119 of ${\beta}-casein$.

• Molecules and Cells
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• v.20 no.1
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• pp.83-89
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• 2005

HtrA2/Omi is a mammalian mitochondrial serine protease homologous to the E. coli HtrA/DegP gene products. Recently, HtrA2/Omi was found to have a dual role in mammalian cells, acting as an apoptosis-inducing protein and being involved in maintenance of mitochondrial homeostasis. By screening a human brain cDNA library with $A{\beta}$ peptide as bait in a yeast two-hybrid system, we identified HtrA2/Omi as a binding partner of $A{\beta}$ peptide. The interaction between $A{\beta}$ peptide and HtrA2/Omi was confirmed by an immunoblot binding assay. The possible involvement of HtrA2/Omi in $A{\beta}$ peptide metabolism was investigated. In vitro peptide cleavage assays showed that HtrA2/Omi did not directly promote the production of $A{\beta}$ peptide at the ${\beta}/{\gamma}$-secretase level, or the degradation of $A{\beta}$ peptide. However, overexpression of HtrA2/Omi in K269 cells decreased the production of $A{\beta}40$ and $A{\beta}42$ by up to 30%. These results rule out the involvement of HtrA2/Omi in the etiology of Alzheimer's disease. However, the fact that overexpression of HtrA2/Omi reduces the generation of $A{\beta}40$ and $A{\beta}42$ suggests that it may play some positive role in mammalian cells.

• Journal of the Korean Magnetic Resonance Society
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• v.11 no.1
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• pp.24-29
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• 2007

[ ${\beta}ig-h3$ ] is an extracellular matrix protein that mediates cell adhesion through interaction with integrins. The 18 residue YH motifs within each fas-1 domain are known to be responsible for the interaction with the ${\alpha}_v{\beta}_5$ integrin, and the synthetic YH motif peptides are known to inhibit endothelial tube formation and reduces the number of blood vessels, and so expected to be an effective inhibitor of angiogenesis. In this study, we solved the 3D structure of the 18 residue YH motif peptide (EALRDLLNNHILKSAMCA; D2 peptide) within the second fas-1 domain of ${\beta}ig-h3$ using NMR. The Peptide has ${\alpha}-helix$ structure at the C terminal region but the N terminal region is flexible. The present structural information may be helpful for developing more effective peptide drug candidate for the treatment of diseases dependent on angiogenesis.

• 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 the Korean Applied Science and Technology
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• v.35 no.3
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• pp.956-962
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• 2018

Childhood obesity causes a higher risk of obesity, premature death and disability in adulthood. In addition, obese children experience an increased risk of respiratory problems, hypertension, cardiovascular disease, insulin resistance and psychological effects. This study aimed to investigate how an exercise intervention affects health-related physical fitness and inflammatory-related blood factors in obese children after. We hypothesized that there would be positive effects on serum levels of insulin-like growth factor-1 (IGF-1), connecting peptide(C-peptide) and resistin, as well as in muscle and cardiovascular-related physical capacities, after an exercise intervention in obese children. Thirty-seven obese children haveperformed health-related fitness tests and provided blood samples for the analysis of changes in circulating biomarkers, both before and after an 8-week exercise intervention, which includes stretching, aerobic exercise, resistance exercise and sports games. The results indicate that exercise training beneficially affects body compositions, especially percentage body fat and muscle mass, without influencing to body weight and height. The results of the physical fitness tests show that muscle and cardiovascular capacity were increased in obese children in response to exercise training. Simultaneously, the exercise training decreased circulating levels of C-peptide, which equated to a "large" effect size. Although there were no significant effects on the levels of IGF-1 and resistin, they show a "small" effect size. Therefore, our findings suggest that the exercise intervention have beneficial effects on body composition and physical fitness levels in obese children, whichmight be associated with the decline in circulating C-peptide.

• Journal of Microbiology and Biotechnology
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• v.27 no.4
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• pp.759-767
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• 2017

Lactophoricin (LPcin), which is a part of proteose peptone isolated from bovine milk, is a cationic amphipathic ${\alpha}-helical$ antimicrobial peptide. Its truncated variants and mutated analogs were designed and their antimicrobial activities were evaluated by using various assays, like broth dilution methods and disk diffusion methods as well as hemolysis assay. Three analogs, LPcin-C8 (LPcin-YK1), LPcin-T2&6W (LPcin-YK2), and LPcin-T2&6W-C8 (LPcin-YK3), which showed better antibiotic activities than LPcin, were selected. Their secondary structures were also characterized by using CD spectropolarimetry. These three analogs of LPcin could be used as an alternative source of powerful antibacterial agents.

• Applied Biological Chemistry
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• v.41 no.8
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• pp.572-577
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• 1998

The solution conformation of the human insulin precursor, preproinsulin, is described in terms of NMR spectral data. NMR experiments were performed on preproinsulin, whose structure was compared with the NMR structure of native human insulin. Despite the presence of the C-peptide and/or the signal peptide, secondary structure analyses indicate that the native structures of the A and B chains are well conserved even in preproinsulin. The observed relative robustness of the native structure in precursor forms permits further protein engineering experiments where the C-peptide or N-terminal signal sequence can be altered for the purpose of increasing expression or purification yields when producing recombinant human insulin.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.284-292
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• 2018

Receptor for advanced glycation end-products (RAGE) is overexpressed in various cancer cells. In this study, a RAGE-binding peptide (RBP) was conjugated to polyethylenimine (25 kDa, PEI). RBP-conjugated PEI (PEI-RBP) was characterized as a dual-functional reagent, a RAGE-mediated gene carrier and an anti-angiogenic reagent. As a gene carrier, PEI-RBP had higher transfection efficiency to the C6 glioblastoma cells than PEI. As an anti-angiogenic reagent, the pEmpty/PEI-RBP complex reduced RAGE expression on the surface of the C6 glioblastoma cells. Also, the complex reduced the VEGF expression and tube formation of endothelial cells. Therefore, PEI-RBP may be useful for development of glioblastoma therapy.

• IMMUNE NETWORK
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• v.14 no.4
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• pp.219-225
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• 2014

We examined the immunogenicity of H-2 class I-restricted and HLA-A2-restricted epitopes through peptide immunization of HLA-A2-transgenic mice that also express mouse H-2 class I molecules. All four of the tested epitopes restricted by H-2 class I robustly elicited T-cell responses, but four of seven epitopes restricted by HLA-A2 did not induce T-cell responses, showing that HLA-A2-restricted peptide epitopes tend to be poorly immunogenic in HLA-A2-transgenic mice. This finding was confirmed in HLA-A2-transgenic mice infected with a recombinant vaccinia virus expressing hepatitis C virus proteins. We examined the precursor frequency of epitope-specific naïve $CD8^+$ T cells in HLA-A2-transgenic and conventional C57BL/6 mice and found that the poor immunogenicity of HLA-A2-restricted peptide epitopes is related to the paucity of naïve $CD8^+$ T-cell precursors in HLA-A2-transgenic mice. These results provide direction for the improvement of mouse models to study epitope repertoires and the immunodominance of human T-cell responses.

• International Journal of Industrial Entomology and Biomaterials
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• v.17 no.1
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• pp.137-141
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• 2008

We previously isolated and cloned a cDNA of abaecin from the Bombus ignitus. In an effort to produce a large amount of soluble abaecin at low cost, we successfully expressed the peptide in Escherichia coli that are highly sensitive to its mature form. For this, we fused the peptide encoding 39 amino acids of mature B. ignitus abaecin to the thioredoxin gene together with a C-terminal 6xHis tag. An enterokinase cleavage site was introduced between the 6xHis tag and mature abaecin to allow final release of the recombinant peptide. A high yield of 9.6 mg soluble fusion protein from 200 ml of bacterial culture was purified by $Ni^{2+}$-charged His-Bind resin affinity column, and 1.4 mg of pure active recombinant abaecin was readily obtained by enterokinase cleavage, followed by affinity chromatograph. The molecular mass of recombinant abaecin peptide was determined by Tricin-SDS-PAGE analysis. The recombinant abaecin exhibited antibacterial activity against Gram-negative bacteria.