• Journal of Microbiology and Biotechnology
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• 제9권3호
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• pp.276-281
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• 1999

In order to determine the functional region of the antifungal protein (AFP) isolated from Aspergillus giganteus responsible for growth inhibitory activity and the promotion of phospholipid vesicle aggregation, overlapping peptides covering the complete sequence of AFP were synthesized. The antibiotic activity against bacterial, fungal, and tumor cells, and the vesicle-aggregation activity of the synthetic peptides were investigated. The AFP functional sequence responsible for antibiotic and vesicle-aggregation activity was determined to be located within the region between AFP residues 19 to 32. AFP (19-32) exhibited an a-helical conformation in a cell membrane-like environment. AFP (19-32) displayed potent antibiotic activity against bacterial, fungal, and tumor cells without peptide toxicity as indicated by hemolysis. Accordingly, AFP (19-32) could be used as a good model for the design of effective antibiotic agents with powerful antibiotic activity yet without any cytotoxic effects against the host organism.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 춘계학술발표대회
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• pp.8.1-8.1
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• 2009

The self-assembly of peptide-based building blocks into nanostructures is an attractive route for fabricating novel materials because of their capacity for molecular recognition and functional flexibility as well as the mild conditions required in the fabrication process. Among various peptide-based building blocks forming nanostructures, the simplest building blocks are aromatic dipeptides like diphenylalanine, which can readily self-assemble into nanotubes in aqueous solutions at ambient conditions. Recently, we have developed a high-temperature solid-phase self-assembly process for diphenylalanine. Through this novel process, we succeeded in the growth of vertically well-aligned, uniform nanowires from amorphous peptide thin film. To demonstrate the versatility of our approach, we also fabricated a micropattern of peptide nanowires by combining our solid-phase growth method and simple soft lithographic techniques. We believe that our studies on peptide self-assembly will provide a new horizon for peptide-based nanofabrication.

• 한국축산식품학회지
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• 제43권1호
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• pp.184-194
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• 2023

Recently, interest in food-derived bioactive peptides as promising ingredients for the prevention and improvement of hypertension is increasing. The purpose of this study was to determine the structure and antihypertensive effect of an antioxidant peptide purified from velvet antler in a previous study and evaluate its potential as a various bioactive peptide. Molecular weight (MW) and amino acid sequences of the purified peptide were determined by quadrupole time-of-flight electrospray ionization mass spectroscopy. The angiotensin I-converting enzyme (ACE) inhibition activity of the purified peptide was assessed by enzyme reaction methods and in silico molecular docking analysis to determine the interaction between the purified peptide and ACE. Also, antihypertensive effect of the purified peptide in spontaneously hypertensive rats (SHRs) was investigated. The purified antioxidant peptide was identified to be a pentapeptide Asp-Asn-Arg-Tyr-Tyr with a MW of 730.31 Da. This pentapeptide showed potent inhibition activity against ACE (IC₅₀ value, 3.72 μM). Molecular docking studies revealed a good and stable binding affinity between purified peptide and ACE and indicated that the purified peptide could interact with HOH2570, ARG522, ARG124, GLU143, HIS387, TRP357, and GLU403 residues of ACE. Furthermore, oral administration of the pentapeptide significantly reduced blood pressure in SHRs. The pentapeptide derived from enzymatic hydrolysate of velvet antler is an excellent ACE inhibitor. It might be effectively applied as an animal-based functional food ingredient.

• 한국식품저장유통학회지
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• 제24권4호
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• pp.542-549
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• 2017

In this study, a peptide exhibiting antioxidant activity was isolated from sandfish (Arctoscopus japonicus) roe hydrolysate (SRH) in order to evaluate their practical uses as materials for manufacturing functional foods. The A. japonicus roe protein was hydrolyzed using Collupulin MG, and isolation of antioxidant peptide was performed using ultrafiltration (UF), prep-HPLC, and RP-HPLC. The SRH with a molecular weight below 3 kDa constituted about 38% of the whole hydrolysate, and the fraction with a molecular weight below 3 kDa showed significantly greater antioxidant activity compared to the original SRH and other fractions. The isolation fold of the antioxidant peptide isolated from SRH throughout the four-step procedure was 7.11-fold, and protein yield was 14.8%. The DPPH radical scavenging activity of isolated antioxidant peptide was above 90% at a concentration of 1.0 mg/mL, which was similar to that of the Trolox at a concentration of 0.1 mg/mL. These results suggested that the antioxidant peptide derived from A. japonicus roe could be a useful additive for producing functional foods and protein supplements. However, it is necessary to perform further study the structural characteristics of this antioxidant peptide isolated from A. japonicus roe.

• Bulletin of the Korean Chemical Society
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• 제32권2호
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• pp.503-509
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• 2011

New types of lariat type crown ethers containing peptide sidearms were prepared by using a novel strategy employing single electron transfer (SET)-induced photocyclization reactions of $\alpha$-silylether terminated phthalimides. Reactions of chiral substrates in this series produced diastereomeric mixtures of crown ether products as a result of the formation of new stereogenic center generation in the photocyclization process.

• 한국환경과학회지
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• 제22권11호
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• pp.1465-1471
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• 2013

To develop the protein materials by the reutilization of dead flatfish from fish farms in Jeju island, the physicochemical characteristics and the functional activities of collagen peptide extracts were investigated. Flatfish skin collagen peptide (FSCP) and flatfish protein hydrolysate (FPH) were manufactured from dead flatfish. The differences of pH, moisture and fat contents between FSCP and FPH were not significant, fat contents were analyzed less than 0.3%, and trans-fat, saturated fat and cholesterol were not detected in both samples. Protein contents of FSCP and FPH showed about 92% and 95%, respectively. In the analysis of amino acids, glycine and hydroxy proline content in FSCP was 24.22% and 6.15%, respectively, showed a typical characteristics of the collagen protein, but essential amino acids contents such as threonine, valine, methionine, isoleusine, leusine and phenylalanine were relatively higher than those of FPH. Average molecular weight of FSCP was measured as 1,102 which was almost equal value with that of tuna collagen peptide. The antioxidant activities and functional properties showed high but did not show significant difference between two samples.

• Bulletin of the Korean Chemical Society
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• 제32권12호
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• pp.4337-4340
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• 2011

The vitamin D receptor binding peptide, VDRBP, was overexpressed as a fused form with the ubiquitin molecule in Rosetta(DE3)pLysS, a protein production strain of Escherichia coli harboring an induction controller plasmid. The fusion protein was bound to the immobilized metal ions, and the denaturation and renaturation of the fusion protein were performed as a part of the purification procedure. After the elution of the fusion protein, the peptide hormone was released from its fusion partner by using yeast ubiquitin hydrolase (YUH), and subsequently purified by reverse phase chromatography. The purity of the resulting peptide fragment was checked by MALDI-TOF mass and NMR spectroscopy. The final yields of the target peptide were around 5 and 2 mg per liter of LB and minimal media, respectively. The recombinant expression and purification of this peptide will enable structural and functional studies using multidimensional NMR spectroscopy and X-ray crystallography.

• Journal of Microbiology and Biotechnology
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• 제11권5호
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• pp.798-803
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• 2001

Peptide synthetases produced from various microorganisms are multifunctional enzyme complexes and their substrates are recognized and activated by adenylation domains. To identify the substrate specificity of the peptide synthetase isolated from Bacillus subtilis 713, known to produce an antifungal peptide, two adenylation domains containing the minimal functional portion were expressed and purified. ATP-ppi exchange experiments and kinetic studies revealed that the two adenylation enzymes had a substrate specificity to $_{L}-lysine{\;}and{\;}_{L}-tryptophan$, respectively. In addition, based on a signature sequence comparison, the substrate of the third domain was predicted to be L-glutamic acid. These results suggest that this peptide synthetase is novel because there has been no previous report on a peptide synthetase that uses $_{L}-lysine,{\;}_{L}-tryptophan,{\;}and{\;}_{L}-glutamic$ acid as substrates in that order.

• Bulletin of the Korean Chemical Society
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• 제35권3호
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• pp.770-774
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• 2014

The bond dissociation energy (BDE) of the chemical bond between the carbon and oxygen atoms of a simple TEMPO-derivative is calculated by employing the density functional theory, the $2^{nd}$ order M${\phi}$ller-Plesset (MP2) perturbation theory, and complete basis set (CBS) methods. We find that BDE of the positive ion of the TEMPO-derivative is larger at least by 7 kcal/mol than that of the negative ion, which implies that the dissociation reaction rate of the positive ion should be slower than that of the negative ion. Such theoretical predictions are contrary to the results of our previous experiments (Anal. Chem. 2013, 85, 7044), in which the larger energy was required for negative o-TEMPO-Bz-C(O)-peptides to undergo the dissociation reactions than for the positive ones. By comparing our theoretical results to those of the experiments, we conclude that the dissociation reaction of o-TEMPO-Bz-C(O)-peptide should occur in a complicated fashion with a charge, either positive or negative, probably being located on the amino acid residues of the peptide.

• 동아시아식생활학회지
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• 제12권5호
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• pp.364-369
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• 2002

본 연구는 천연 자원인 뽕나무에서 혈당강하 효능을 가진 뽕잎(상엽)의 열수 추출법을 이용하여 상엽 추출물의 공정화 확립과 Formulation 개발을 위해 상엽 추출물과 silk peptide 및 한약재를 첨가한 시제품을 동물실험을 통하여 Formulation을 최종 결정하여 제품화하여 기능성 음료를 개발하고자 하였다. 연구 결과, 상엽 추출의 최적 조건은 상엽 크기는 3mm 이하로 하고, 2/3 정도 packing된 면포자루로 포장된 상엽을 사용하며, 상엽 사용량은 50~100 g/L, 추출 온도는 9$0^{\circ}C$, 추출 시간은 2 hr으로 하였으며 이때 수율은 20~25%였다. 또한 시료 배합에 따른 혈당강하 실험을 통하여 상엽 추출물과 silk peptide 의 농도는 각각 1%, 0.1%일 때 혈당강하 작용이 가장 우수하였으며 부재료로 사용된 둥글레는 상엽추출물의 10% 첨가한 경우가 혈당강하작용이 가장 컸으며, polydextrose도 효과가 있으므로 첨가하는 것이 바람직하다고 사료된다.