• KSBB Journal
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• 제29권5호
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• pp.380-384
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• 2014

Inhibition effects of peptide hydrolysates from Astragalus membranaceus Bunge. on the expression of the matrix metalloproteinases (MMPs) in human dermal fibroblasts were evaluated in vitro. Crude peptides were obtained by the hydrolysis of proteins extracted from A. membranaceus. Peptides were purified partially by the basis on the molecular weight using 40% polyacrylamide gel electrophoresis before treatment with human dermal fibroblasts. Basis on the doseeffect experiments, expressions of MMPs including MMP-1, MMP-3, MMP-8, MMP-13 in human dermal fibroblasts were evaluated. Expressions of MMP-1, MMP-3, MMP-8 and MMP-13 were reduced in 43%, 5%, 22% and 57% respectively. The mass spectrometric analysis of partially purified peptides from A. membranaceus, which strongly inhibit expressions of MMPs, indicated that the peptides were composed of molecules below 1500 Da.

• 한국해양바이오학회지
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• 제7권1호
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• pp.19-27
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• 2015

The objective of the current study was to evaluate the inhibitory and antioxidant activities of powdered katsuobushi (dried bonito) protein hydrolysates and their corresponding fractions. The powdered katsuobushi (dried bonito) hydrolysates were obtained by enzymatic hydrolysis using Alcalase, ${\alpha}$-chymotrypsin, Neutrase, pepsin, papain, and trypsin. The antioxidant efficacy of the respective hydrolysates were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, superoxide, and alkyl radical-scavenging activities. Among the hydrolysates, the peptic-derived hydrolysate exhibited the highest antioxidant activity compared to other enzymatic hydrolysates. Therefore, the peptic-derived hydrolysate was further analyzed, and was found to contain an active peptide with an amino acid sequence identified as Pro-Met-Pro-Leu-Asn-Ser-Cys (756 Da). The purified peptides from powdered katsuobushi (dried bonito) had an $EC_{50}$ value of $105.82{\mu}M$, and exhibited an inhibitory effect against DNA oxidation induced by hydroxyl radicals. Taken together, these results suggests that powdered katsuobushi (dried bonito) could be used as a natural antioxidant in functional foods and prevent oxidation reactions in food processing.

• 한국식품영양과학회지
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• 제42권7호
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• pp.1162-1166
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• 2013

해바라기씨박 단백질 가수분해물로부터 철분 결합 펩타이드를 분리하기 위해 해바라기씨박 단백질을 단백 가수분해 효소인 alcalase와 flavourzyme을 이용하여 가수분해하였고, 가수분해물을 3 kDa 이하로 한외여과를 하였다. 한외여과된 가수분해물은 QAE Sephadex$^{TM}$ A-25 column과 Superdex$^{TM}$ peptide 10/300 GL column을 사용하여 철분 결합 펩타이드를 분리하였고, 분리된 분획 중 철분 결합력이 가장 높은 F22를 얻었다. 본 연구에서 얻어진 해바라기씨박 단백질 가수분해물로부터 분리된 분획들은 향후 기능성식품 소재 원료로 사용될 수 있다고 판단된다.

• 생명과학회지
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• 제10권2호
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• pp.210-217
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• 2000

A kinetic profile of the catalytic domain of stromelysin-1 (SCD) using the fluorescent peptide substrate has been determined by the stopped-flow technique. The pH profile has a pH optimum of about 5.5 with an extended shoulder above pH 7. Three pKa values, 5.0, 5.7, and 9.8 are found for the free enzyme state and two pH independent Kcat/Km values of 4.1$\times$104 M-1 s-1 and 1.4$\times$104 M-1 s-1 at low and high pH, respectively. The profile is quite different in shape with other MMP family which has been reported, having broad pH optimum with two pKa values. The substrate specificity of SCD towards fluorescent heptapeptide substrates has been also examined by thin layer chromatography. The cleavage sites of the substrates have been identified using reverse-phase HPLC method.SCD cleaves Dns-PLA↓L↓WAR and Dns-PLA↓L↓FAR at two positions. However, the Dns-PLA↓LRAR, Dns-PLE↓LFAR, adn Dns-PLSar↓LFAR are cleaved exclusively at one bond. The double cleavages of Dns-PLALWAR and Dns-PLALFAR by SCD are in marked contrast to the close structurally related matrilysin. A notable feature of SCD catalysis agrees with the structural data that the S1' pocket of SCD is deeper than that of matriysin. The differences observed between SCD and matrilysin may form the basis of understanding the structural relationships and substrate specificities of the MMP family in vivo.

• 대한화학회지
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• 제14권2호
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• pp.155-160
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• 1970

The kinetics of the pepsin-catalyzed hydrolysis of N-carbobenzoxy-L-glutamyl-L-tyrosine at pH 3.5 and $37^{\circ}C$ were determined by a spectrophotometric technique. The pepsin used was further purified on a Sephadex G-75 column. The kinetics data were Km = l.7 ${\times}10^{-3}M,\;-{\Delta}F^{\circ}$ = 3.99Kcal/mole, and $k^3=\;2.1{\times}10^{-2}\;sec^{-1}$. An analysis of the above data and other investigators' data obtained from some dipeptides led to the following conclusions. (1) Phenylalanyl residues in a synthetic peptide are bound to pepsin more strongly than glutamyl or tyrosyl residues, supporting the theory that a part of the binding region of the active center is hydrophobic. (2) Dipeptides are bound to pepsin principally through their side chains and the binding involves both side-chain residues. (3) The nature of amino acids in dipeptides $R_2-R_1,\;affect\;the\;k_3$ values.

• Journal of Microbiology and Biotechnology
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• 제23권12호
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• pp.1779-1784
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• 2013

Although enzyme-hydrolyzed silk fibroin has been reported to enhance cognitive function before, it has been still unknown which peptides can improve memory. Here we report that amino acid sequences of three novel peptides were identified from fibroin hydrolysate. Fibroin hydrolysate was obtained by hydrolysis with protease after partial hydrolysis with 5M $CaCl_2$. Synthesized peptides derived from these sequences improved scopolamine-induced memory impairments in mice. We confirmed this hydrolysate had effects that improved learning and memory abilities by performing the Rey-Kim test. From this hydrolysate of silk fibroin, amino acid sequences of eight peptides were identified by LC-MS/MS. Three peptides (GAGAGTGSSGFGPY, GAGAGSGAGSGAGAGSGAGAGY, and SGAGSGAGAGSGAGAGSGA) were synthesized to investigate whether they could improve memory. Passive avoidance test and Morris water maze test were performed, and all peptides showed memory-enhancing abilities on scopolamine-induced memory impairments in mice. In this study, we identified three novel peptides that could improve memory, and that silk fibroin hydrolysate was a mixture of various active peptides that could enhance memory.

• 한국식품과학회지
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• 제2권2호
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• pp.43-48
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• 1970

When of the synthetic peptides were subjected hydrolysis with Mucor-rennin which crystalline milk-clotting enzyme from Mucor pusillus, the peptides of Z-L-Glu-L- Phe-OH, Z-L-Phe-L-Tyr-OH, Z-L-Phe-L-Leu-OH, Z-L-Tyr-L-Leu and Z-L-Glu-L-Phe-OH, were found to be hydrolysis.

• 한국잠사곤충학회지
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• 제39권2호
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• pp.197-202
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• 1997

To hydrolyze silk fibroin was treated with NaOH solution on various concentrations and times. And it was examined that the addition effects of NaHSO3 solution on the solubility and colouring of silk fibroin. As obtained results are as follows; The more increasement of concentration and time of NaOH treatment, the more increasement of solubility but solubility was slight above 3% concentration of NaOH. Fibroin yield was decreased above 3% concentration. This was due to formation of peptide or amino acids below molecular weight 3,000. Most of molecular weight distribution came out to be under 3,000 in 2% concentration and 4hrs of NaOH treatment. The more increasement of adding concentration and 4hrs of NaOH treatment. The more increasement of adding concentration of NaHSO3, the more reduction of solubility but white index of powder increased. In the results of FT-IR spectras of silk fibroin powder obtained by various concentrations of NaHSO3 treatment, the absorbent peak at 3,400 cm-1 which was considered as -CH=N- (azomethine) was disappeared by the more addition of NaHSO3. It showed that absorbent peak of $\beta$-fibroin moved into low temperature region and transferred to $\alpha$- and random coil structure through the DSC experiment. In the results of amino acid analysis, alkali hydrolysis reduced the oxy amino contents acid like serine and tyrosine, but increased the glycine content by the more addition of NaHSO3.

• 농업과학연구
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• 제39권4호
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• pp.561-568
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• 2012

The aim of this study was to introduce a simple method for isolation of ${\alpha}$-lactalbumin, ${\beta}$-lactoglobulin and bovine serum albumin from cow's milk, and peptides produced by enzymatic hydrolysis of ${\alpha}$-lactalbumin, ${\beta}$-lactoglobulin and bovine serum albumin with alcalase. Whey protein were precipitated from whey by ammonium sulfate and, ${\alpha}$-lactalbumin and ${\beta}$-lactoglobulin were isolated using Hi Prep 26/60 Sephacryl S-100 column gel filtration chromatography. Bovine serum albumin and ${\beta}$-lactoglobulin were isolated by Mono-Q 5/50 GL column anion exchange chromatography of the 50% Ammonium Sulfate-supernatant. Isolated whey proteins were hydrolyzed by proteolytic alcalase. Tricine SDS-PAGE and reverse-phase HPLC analyses revealed that almost hydrolyzed all the ${\alpha}$-lactalbumin, ${\beta}$-lactoglobulin and bovine serum albumin with alcalase. Molecular weight of various peptides derived from alcalase hydrolysate were small molecular weight than 3.5 kDa.

• 한국식품저장유통학회지
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• 제22권2호
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• pp.297-302
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• 2015

저활용 단백질로부터 칼슘 결합물질을 분리하기 위해 돼지 육골분과 진주담치 단백질을 단백질 분해 효소인 alcalase를 이용하여 가수분해물을 제조하였고, 체내 흡수가 용이한 3 kDa 이하로 한외여과 하였다. 돼지 육골분 가수분해물은 Mono Q 컬럼을 통해 분리하였고, 진주담치 가수분해물의 경우 Q-Sepharose로 분리 하여 각각 2개, 3개의 peptide fraction을 얻어 각 fraction의 칼슘 결합력을 측정하였다. 그 결과 MBM F2와 Mussel F3에서 가장 높은 칼슘 결합력을 나타내었고, 따라서 본 연구 결과로 얻어진 가수분해물들은 칼슘 보충 소재로 활용될 수 있다고 판단된다.