Hee-Guk Byun

Gangneung-Wonju National University, Wŏnju, Gangwon, South Korea

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Publications (34)54.98 Total impact

  • Article: Nitric oxide-mediated vasorelaxation effects of anti-angiotensin I-converting enzyme (ACE) peptide from Styela clava flesh tissue and its anti-hypertensive effect in spontaneously hypertensive rats.
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    ABSTRACT: In our previous study, an anti-angiotensin I converting enzyme (ACE) peptide (Ala-His-Ile-Ile-Ile, MW: 565.3Da) was isolated from Styela clava flesh tissue. In this study the fractions obtained during the isolation process and the finally purified peptide were examined to see if they had vasorelaxation effects in isolated rat aortas, and then the peptide was investigated for anti-hypertensive effect in spontaneously hypertensive rats (SHRs). The induction of vasorelaxation in the rat aortas was observed with the isolated fractions and the peptide from the enzymatic hydrolysate of S. clava flesh tissue and could be markedly blocked by pretreatment with the nitric oxide synthase (NOS) inhibitor, N(G)-nitro-l-arginine methyl ester (l-NAME). In human endothelial cells, NO synthesis was found to be increased and eNOS phosphorylation was upregulated when the cells were cultured with the purified peptide. Furthermore, systolic blood pressure was reduced by administration of the potent vasorelaxation peptide in SHRs.
    Food Chemistry 09/2012; 134(2):1141-5. · 3.65 Impact Factor
  • Article: Lipase-catalyzed hydrolysis of fish oil in an optimum emulsion system
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    ABSTRACT: In this study, fish oil was hydrolyzed by lipase in a fish oil-in-water emulsion system in an effort to improve the functional properties of fish oil. Lipase activity was found to depend on the quality of the water/fish oil interface area. We selected several suitable emulsifiers, and their emulsifying activities were evaluated under a variety of conditions, including concentration, water-oil ratios, pH values, and temperature. Among the selected emulsifiers, the emulsifying activity of gelatin was higher than those of carboxymethyl chitin (CM-chitin), bovine serum albumin, and Tween-20, all of which are commercial emulsificers Moreover, the emulsifying activity of the gelatin solution was the highest at 0.5%, and was reduced with increasing concentrations of above 1%. The optimal water-oil ratio, pH, and temperature conditions were 40% (w/v), pH 8.0 and 40°C, respectively. Under these conditions, the emulsifying activity of gelatin solution was 86%. The emulsion structure of the gelatin solution was characterized by high density and small particle size. The degree of sardine oil hydrolysis in the emulsion system was 50% higher than that of the non-emulsion system. The lipid species of the lipase-prepared sardine oil hydrolysates were identified as triacylglycerol, 1,3- and 1,2-diacylglycerol, monoacylglycerol, and fatty acid.
    Biotechnology and Bioprocess Engineering 04/2012; 12(5):484-490. · 1.28 Impact Factor
  • Article: Lipase catalyzed production of monoacylglycerols by the esterification of fish oil fatty acids with glycerol
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    ABSTRACT: In this study, we attempted the efficient production of monoacylglycerols (MAG) via the lipase-catalyzed esterification of glycerol with fatty acids obtained from sardine oil. The reaction factors that influenced MAG synthesis were the glycerol to fatty acid mole ratio, amount of enzyme, organic solvent, temperature, and the type of lipase used. Porcine pancreas lipase was selected to catalyze this reaction. The optimum conditions we determined for MAG synthesis were a glycerol to fatty acid mole ratio of 1∶6, 100 mg/mL of lipase, and 30°C in dioxane. Under these conditions, the MAG content was 68% (w/w) after 72 h of reaction. The MAGs synthesized via the lipase-catalyzed esterification of glycerol with fatty acids included monomyristin, monopamiltin, and monoolein, as identified by GCMS.
    Biotechnology and Bioprocess Engineering 04/2012; 12(5):491-496. · 1.28 Impact Factor
  • Source
    Article: Continuous production of citric acid from dairy wastewater using immobilizedAspergillus niger ATCC 9142
    Se-Kwon Kim, Pyo-Jam Park, Hee-Guk Byun
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    ABSTRACT: The continuous production of citric acid from dairy wastewater was investigated using calcium-alginate immobilizedAspergillus niger ATCC 9142. The citric acid productivity and yield were strongly affected by the culture conditions. The optimal pH, temperature, and dilution rate were 3.0, 30°C, and 0.025 h−1, respectively. Under optimal culture conditions, the maximum productivity, concentration, and yield of citric acid produced by the calcium-alginate immobilizedAspergillus niger were 160 mg L−1 h−1, 4.5 g/L, and 70.3% respectively. The culture was continuously perfored for 20 days without any apparent loss in citric acid productivity. Conversely, under the same conditions with a batch shake-flask culture, the maximum productivity, citric acid concentration, and yield were only 63.3 mg L−1 h−1, 4.7 g/L and 51.4%, respectively. Therefore, the results suggest that the bioreactor used in this study could be potentially used for continuous citric acid production from dairy wastewater by applying calcium-alginate immobilizedAspergillus niger.
    Biotechnology and Bioprocess Engineering 04/2012; 7(2):89-94. · 1.28 Impact Factor
  • Article: β-secretase inhibitory activity of phenolic acid conjugated chitooligosaccharides.
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    ABSTRACT: Eight kinds of phenolic acid conjugated chitooligosaccharides (COSs) were synthesized using hydroxyl benzoic acid and hydroxyl cinnamic acid. These phenolic acid conjugated-COSs with different substitution groups, including p-hydroxyl, 3,4-dihydroxyl, 3-methoxyl-4-hydroxyl and 3,5-dimethoxyl-4-hydroxy groups, were evaluated for their inhibitory activities against β-site amyloid precursor protein (APP)-cleaving enzyme (BACE) and inhibited BACE with a ratio of 50.8%, 74.8%, 62.1%, 64.8% and 42.6%, respectively at the concentration of 1,000 μg/mL. BACE is a critical component to reduce the levels of Aβ amyloid peptide in Alzheimer's disease (AD) which is based on the amyloid cascade theory in the brain, as this protease initiates the first step in Aβ production. Among them, Caffeic acid conjugated-COS (CFA-COS) was further analysed to determine mode of inhibition of BACE and it showed non-competitive inhibition. Hence in this study, we suggest that CFA-COS derivatives have potential to be used as novel BACE inhibitors to reduce the risk of AD.
    Journal of Enzyme Inhibition and Medicinal Chemistry 03/2012; · 1.62 Impact Factor
  • Article: Characterization of bioactive peptides obtained from marine invertebrates.
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    ABSTRACT: Bioactive peptides as products of hydrolysis of diverse marine invertebrate (shellfish, crustacean, rotifer, etc.) proteins are the focus of current research. After much research on these muscles and by-products, some biologically active peptides were identified and applied to useful compounds for human utilization. This chapter reviews bioactive peptides from marine invertebrates in regarding to their bioactivities. Additionally, specific characteristics of antihypertensive, anti-Alzheimer, antioxidant, antimicrobial peptide enzymatic production, methods to evaluate bioactivity capacity, bioavailability, and safety concerns of peptides are reviewed.
    Advances in food and nutrition research 01/2012; 65:47-72.
  • Article: Anti-obesity effect of carboxymethyl chitin by AMPK and aquaporin-7 pathways in 3T3-L1 adipocytes.
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    ABSTRACT: The aim of this study was to investigate the anti-obesity effect of carboxymethyl-chitin (CM-chitin), a water-soluble derivative of chitin, by measuring lipid accumulation and adipogenesis related factors in 3T3-L1 adipocytes. CM-chitin was synthesized by means of carboxymethylation reaction. Its inhibitory effect on lipid accumulation was investigated by measuring triglyceride content and glycerol release level. The gene and protein levels associated with adipogenesis were determined using reverse transcriptase-polymerase chain reaction and Western blot analysis. Treatment with CM-chitin reduced triglyceride content and enhanced glycerol secretion in a dose-dependent manner. CM-chitin induced the down-regulation of adipogenesis related transcriptional factors and adipocyte specific gene promoters. Moreover, the specific mechanism by CM-chitin was confirmed by transcriptional activations of the phosphorylated adenosine monophosphate-activated protein kinase (AMPK) and aquaporin-7. These results suggest that CM-chitin exerts anti-adipogenic effect on lipid accumulation through modulations of AMPK and aquaporin-7 signal pathways.
    The Journal of nutritional biochemistry 03/2011; 22(3):276-81. · 4.29 Impact Factor
  • Article: Angiotensin I converting enzyme inhibitory peptide extracted from freshwater zooplankton.
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    ABSTRACT: In this study, hydrolysates obtained from the freshwater rotifer Brachionus calyciflonus were investigated for angiotensin I converting enzyme (ACE) inhibitory peptides. Freshwater rotifer protein was hydrolyzed using six separate enzymes in a batch reactor. The peptic hydrolysate had the highest ACE inhibitory activity compared to the other hydrolysates. The highest ACE inhibitory peptide was separated using Sephadex G-25 column chromatography and high-performance liquid chromatography on a C18 column. The 50% inhibitory concentration (IC(50)) value of purified ACE inhibitory peptide was 40.01 microg/mL. ACE inhibitory peptide was identified as being seven amino acid residues of Ala-Gln-Gly-Glu-Arg-His-Arg by N-terminal amino acid sequence analysis. The IC(50) value of purified ACE inhibitory peptide was 47.1 microM, and Lineweaver-Burk plots suggested that the peptide purified from rotifer protein acts as a competitive inhibitor against ACE. The results of this study suggest that peptides derived from freshwater rotifers may be beneficial as antihypertension compounds in functional foods or as pharmaceuticals.
    Journal of medicinal food 02/2010; 13(2):357-63. · 1.39 Impact Factor
  • Article: Purification and characterization of angiotensin I converting enzyme inhibitory peptides from the rotifer, Brachionus rotundiformis.
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    ABSTRACT: Angiotensin I converting enzyme (ACE) inhibitory peptide was isolated from the marine rotifer, Brachionus rotundiformis. ACE inhibitory peptides were separated from rotifer hydrolysate prepared by Alcalase, alpha-chymotrypsin, Neutrase, papain, and trypsin. The Alcalase hydrolysate had the highest ACE inhibitory activity compared to the other hydrolysates. The IC(50) value of Alcalase hydrolysate for ACE inhibitory activity was 0.63 mg/ml. We attempted to isolate ACE inhibitory peptides from Alcalase prepared rotifer hydrolysate using gel filtration on a Sephadex G-25 column and high performance liquid chromatography on an ODS column. The IC(50) value of purified ACE inhibitory peptide was 9.64 microM, and Lineweaver-Burk plots suggest that the peptide purified from rotifer protein acts as a competitive inhibitor against ACE. Amino acid sequence of the peptide was identified as Asp-Asp-Thr-Gly-His-Asp-Phe-Glu-Asp-Thr-Gly-Glu-Ala-Met, with a molecular weight 1538 Da. The results of this study suggest that peptides derived from rotifers may be beneficial as anti-hypertension compounds in functional foods resource.
    Bioresource technology 07/2009; 100(21):5255-9. · 4.25 Impact Factor
  • Article: Inhibitory effects and molecular mechanism of dieckol isolated from marine brown alga on COX-2 and iNOS in microglial cells.
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    ABSTRACT: To identify the neuroprotective effect of dieckol, a hexameric compound of phloroglucinol isolated from marine brown alga, Ecklonia cava , this study investigated the anti-inflammatory effect of dieckol on lipopolysaccharide (LPS)-stimulated murine BV2 microglia and elucidated the molecular mechanism. The results showed that dieckol suppresses LPS-induced production of nitric oxide (NO) and prostaglandin E(2) (PGE(2)) and expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in a dose-dependent manner, without causing cytotoxicity. It also significantly reduced the generation of proinflammatory cytokines, such as interleukin (IL)-1β and tumor necrosis factor (TNF)-α. Moreover, dieckol significantly reduced LPS-induced nuclear factor κB (NF-κB) and p38 mitogen-activated protein kinases (MAPKs) activation, as well as reactive oxygen species (ROS) production. Taken together, the inhibition of LPS-induced NO and PGE(2) production might be due to the suppression of NF-κB and p38 MAPK signal pathway and, at least in part, by inhibiting the generation of ROS. Hence, these effects of dieckol might assist therapeutic treatment for neurodegenerative diseases that are accompanied by microglial activation.
    Journal of Agricultural and Food Chemistry 06/2009; 57(10):4439-46. · 2.82 Impact Factor
  • Article: Purification and antioxidant properties of bigeye tuna (Thunnus obesus) dark muscle peptide on free radical-mediated oxidative systems.
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    ABSTRACT: To produce bioactive peptides from by-products of fish processing, bigeye tuna dark muscle was hydrolyzed using various enzymes (alcalase, alpha-chymotrypsin, neutrase, papain, pepsin, and trypsin), and the hydrolysates were evaluated for antioxidant activity. Considering the results of degree of hydrolysis and antioxidant activities, peptic hydrolysate was used for further studies to identify a potent antioxidant peptide. Antioxidant peptide was purified using consecutive chromatographic methods and was identified as being H-Leu-Asn-Leu-Pro-Thr-Ala-Val-Tyr-Met-Val-Thr-OH (MW 1,222 Da) by quantitative time-of-flight electrospray ionization mass spectrometry. Purified antioxidant peptide from bigeye tuna dark muscle (APTDM) was investigated for its antioxidant activities using both free radical scavenging effects and polyunsaturated fatty acid (PUFA) peroxidation inhibitory activity. The results showed that APTDM effectively quenched with low 50% inhibitory concentration values compared to vitamin C as a positive control against four different free radicals: 1,1-diphenyl-2-picrylhydrazyl, hydroxyl, superoxide, and alkyl radical. APTDM also inhibited PUFA peroxidation in a linoleic acid emulsion system, and the activity was similar to that of alpha-tocopherol. We further investigated its antioxidant activities on cellular systems, and the results showed that APTDM significantly scavenged cellular radicals and enhanced the viability of tert-butyl hydroperoxide-induced cytotoxicity. These results indicate that APTDM or a peptide fraction containing APTDM would be a beneficial ingredient for functional food and/or pharmaceuticals.
    Journal of medicinal food 01/2009; 11(4):629-37. · 1.39 Impact Factor
  • Article: Protective effect of an antioxidative peptide purified from gastrointestinal digests of oyster, Crassostrea gigas against free radical induced DNA damage.
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    ABSTRACT: In this study, in vitro gastrointestinal digestion was employed to obtain potent antioxidative peptide from protein of oyster, Crassostrea gias. The protein was subjected to hydrolysate using consecutive chromatographic methods, on a Hiprep 16/10 diethylaminoethyl fast flow (DEAE FF) anion exchange column and octadecylsilane (ODS) C18 reversed phase column. Finally, the amino acid sequence of the peptide was determined. The peptide, having the amino acid sequence Leu-Lys-Gln-Glu-Leu-Glu-Asp-Leu-Leu-Glu-Lys-Gln-Glu (1.60 kDa), exhibited the higher activity against polyunsaturated fatty acid (PUFA) peroxidation than that of native antioxidant, alpha-tocopherol. The free radical scavenging assay conducted using electron spin resonance (ESR) spectroscopy, clearly exhibited that it scavenged hydroxyl radical and superoxide radical at IC50 values of 28.76 microM and 78.97 microM, respectively. Further, we investigated its antioxidant activities on cellular system, and the results showed that purified peptide significantly scavenged cellular radicals and protective effect on DNA damage caused by hydroxyl radicals generated. Furthermore (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) MTT assay showed no cytotoxicity on human embryonic lung fibroblasts cell line (MRC-5) and mouse macrophages cell (RAW264.7), respectively. These results indicate that this peptide shows potent antioxidant.
    Bioresource Technology 07/2008; 99(9):3365-71. · 4.98 Impact Factor
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    Article: Free radical scavenging activity of a novel antioxidative peptide isolated from in vitro gastrointestinal digests of Mytilus coruscus.
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    ABSTRACT: A low-molecular-weight peptide with potent antioxidative activity was obtained from Mytilus coruscus muscle protein using an in vitro gastrointestinal digestion system. The potent antioxidant peptide, which was identified as Leu-Val-Gly-Asp-Glu-Gln-Ala-Val-Pro-Ala-Val-Cys-Val-Pro (1.59 kDa), exhibited higher protective activity against polyunsaturated fatty acid (PUFA) peroxidation than the native antioxidants, ascorbic acid and alpha-tocopherol. In a free radical scavenging assay using electron spin resonance spectroscopy, hydroxyl radical formation was quenched by 75.04% in the presence of M. coruscus peptide (50 microg/mL), which was similar to ascorbic acid. In addition, the purified peptide could also quench super-oxide and carbon-centered radicals, but those activities were weaker than for ascorbic acid. This study showed that the low-molecular-weight peptide released from in vitro gastrointestinal digestion of mussel exhibited potent antioxidant potential by inhibiting the formation of reactive oxygen species formed by the peroxidation of PUFAs.
    Journal of Medicinal Food 04/2007; 10(1):197-202. · 1.41 Impact Factor
  • Article: PURIFICATION AND CHARACTERIZATION OF A SERINE PROTEINASE FROM THE TUNA PYLORIC CAECA
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    ABSTRACT: ABSTRACTA 15.0 kDa serine proteinase with collagenase activity from pyloric caeca of tuna, Thunnus thynnus, was purified in four steps; acetone precipitation, gel filtration chromatography on a Sephadex G-100, ion-exchange chromatography on a DEAE-Sephadex α-50 and gel filtration chromatography on a Sephadex G-75 column. The purification and yield were 30.5-fold and 0.023%, respectively, as compared with those in the starting crude extract. The optimum pH and temperature for the purified collagenolytic enzyme were around pH 7.5 and 55C, respectively. The purified proteinase was strongly inhibited by metal ions (Hg2+ and Zn2+) and serine proteinase inhibitors (PMSF, TLCK and soybean trypsin inhibitor) suggesting it is a serine protease. The Km and Vmax of the purified enzyme for collagen type I were approximately 3.82 mM and 851.5 U, respectively.
    Journal of Food Biochemistry 02/2007; 26(6):479 - 494. · 0.81 Impact Factor
  • Article: RECOVERY OF FISH BONE FROM HOKI (JOHNIUS BELENGERI) FRAME USING A PROTEOLYTIC ENZYME ISOLATED FROM MACKEREL INTESTINE
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    ABSTRACT: ABSTRACTA new enzymatic treatment procedure was devised to recover and further utilize fish bones from processing which are normally discarded. This procedure includes the use of an enzyme preparation isolated from raw mackerel intestine by acetone precipitation. The caseinolytic activity of mackerel intestine crude enzyme (MICE) was approximately 0.58 U/mg protein, which was comparable to those of trypsin and -chymotrypsin, or even higher than those of papain and Aspergillus saitoi protease. The optimum pH, temperature and enzyme/substrate ratio of MICE for hydrolysis of protein with hoki (Johnius belengeri) frames were determined to be pH 9.0, 40C and 1:100 (w/w). When the hoki frame was treated by MICE for 6 h under the optimum reaction conditions, the yield of bone recovery was approximately 90%. Compared to Alcalase, trypsin, -chymotrypsin and Neutrase, the yield of bone recovery using MICE was higher. These results suggest that MICE may be utilized for bone recovery from fish frame.
    Journal of Food Biochemistry 02/2007; 27(3):255 - 266. · 0.81 Impact Factor
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    Article: Phlorotannins in Ecklonia cava extract inhibit matrix metalloproteinase activity.
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    ABSTRACT: Matrix metalloproteinase (MMP) inhibitors have been identified as potential therapeutic candidates for metastasis, arthritis, chronic inflammation and wrinkle formation. For the first time here we report a detailed study on the inhibitory effects of phlorotannins in brown algae, Ecklonia cava (EC) on MMP activities in cultured human cell lines. A novel gelatin digestion assay could visualize complete inhibition of bacterial collagenase-1 activity at 20 microg/ml of EC extract during preliminary screening studies. Sensitive fluorometric assay revealed that EC extract can specifically inhibit both MMP-2 and MMP-9 activities significantly (P < 0.001) at 10 microg/ml. In addition, artificially induced activities of MMP-2 and MMP-9 in human dermal fibroblasts and HT1080 cells were inhibited by EC extract in a more or less similar manner to the positive control doxycycline. Even though the expression levels of MMPs differ from one cell type to the other, gelatin zymography clearly revealed that both MMP expression and activity in cells can be inhibited by EC extract. More interestingly, EC extract did not exert any cytotoxic effect even at 100 microg/ml anticipating its potential use as a safe MMP inhibitor.
    Life Sciences 09/2006; 79(15):1436-43. · 2.53 Impact Factor
  • Article: Angiotensin I converting enzyme (ACE) inhibitory peptide derived from the sauce of fermented blue mussel, Mytilus edulis.
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    ABSTRACT: The angiotensin I converting enzyme (ACE) inhibitory activity of fermented blue mussel sauce (FBMS) was investigated. Blue mussels were fermented with 25% NaCl (w/w) at 20 degrees C for 6 months and the resultant mixture was passed through a 40-mesh sieve, desalted using an electrodialyzer and then lyophilized. The IC(50) value of FBMS for ACE activity was 1.01 mg/ml. An ACE inhibitory peptide was purified from FBMS using Sephadex G-75 gel chromatography, SP-Sephadex C-25 ion exchange chromatography and reversed-phase high-performance liquid chromatography on a C(18) column. The IC(50) value of purified ACE inhibitory peptide was 19.34 microg/ml, and 10 amino acid residues of the N-terminal sequence was EVMAGNLYPG. The purified peptide was evaluated for antihypertensive effect in spontaneously hypertensive rats (SHR) following oral administration. Blood pressure significantly decreased after peptide ingestion. This result suggested that FBMS may have beneficial effects on hypertension.
    Bioresource Technology 10/2005; 96(14):1624-9. · 4.98 Impact Factor
  • Article: Investigation of jumbo squid (Dosidicus gigas) skin gelatin peptides for their in vitro antioxidant effects.
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    ABSTRACT: Peptides derived from tryptic hydrolysate of jumbo squid (Dosidicus gigas) skin gelatin were assessed for their antioxidant properties in different in vitro assay systems. The hydrolysate itself exhibited a strong lipid peroxidation inhibition and it was much higher than that of natural antioxidant, alpha-tocopherol. In addition, it could scavenge highly active free radicals in oxidative systems, in the order of hydroxyl and carbon-centered radicals. Two representative peptides with comparatively higher antioxidant potency were purified and characterized as Phe-Asp-Ser-Gly-Pro-Ala-Gly-Val-Leu (880.18 Da) and Asn-Gly-Pro-Leu-Gln-Ala-Gly-Gln-Pro-Gly-Glu-Arg (1241.59 Da). Furthermore, viability of radical-mediated oxidation-induced human lung fibroblasts was enhanced following the treatment of two peptides. However it did not exhibit substantial ion chelation, and we presumed that the observed radical scavenging potency of these peptides play a vital role for their strong antioxidant activity. Based on our results we suggest that hydrophobic amino acids present in peptide sequences contributed greatly for observed antioxidant activities.
    Life Sciences 10/2005; 77(17):2166-78. · 2.53 Impact Factor
  • Article: Purification and in vitro antioxidative effects of giant squid muscle peptides on free radical-mediated oxidative systems.
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    ABSTRACT: Low molecular weight peptides obtained from ultrafiltration (UF) of giant squid (Dosidicus gigas) muscle protein were studied for their antioxidative effects in different in vitro oxidative systems. The most potent two peptides, Asn-Ala-Asp-Phe-Gly-Leu-Asn-Gly-Leu-Glu-Gly-Leu-Ala (1307 Da) and Asn-Gly-Leu-Glu-Gly-Leu-Lys (747 Da), exhibited their antioxidant potential to act as chain-breaking antioxidants by inhibiting radical-mediated peroxidation of linoleic acid, and their activities were closer to highly active synthetic antioxidant, butylated hydroxytoluene. Addition of these peptides could enhance the viability of cytotoxic embryonic lung fibroblasts significantly (P<.05) at a low concentration of 50 microg/ml, and it was presumed due to the suppression of radical-induced oxidation of membrane lipids. Electron spin trapping studies revealed that the peptides were potent scavengers of free radicals in the order of carbon-centered (IC(50) 396.04 and 304.67 microM), hydroxyl (IC(50) 497.32 and 428.54 microM) and superoxide radicals (IC(50) 669.34 and 573.83 microM). Even though the exact molecular mechanism for scavenging of free radicals was unclear, unusually high hydrophobic amino acid composition (more than 75%) of giant squid muscle peptides was presumed to be involved in the observed activities.
    The Journal of Nutritional Biochemistry 09/2005; 16(9):562-9. · 3.89 Impact Factor
  • Article: Reactive oxygen scavenging effect of enzymatic extracts from Sargassum thunbergii.
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    ABSTRACT: The free radical scavenging activity of water soluble natural antioxidants from Sargassum thunbergii, which is a brown marine alga, was evaluated by examining the radical scavenging activities of the extracts of hydrolyzates from S. thunbergii on hydroxyl, 1,1-diphenyl-2-picrylhydrazyl (DPPH), and alkyl radicals. A spin-trapping electron spin resonance (ESR) spectrometer was employed, and the results were compared for their ESR signal intensity. S. thunbergii was enzymatically hydrolyzed to prepare water soluble extracts by five carbohydrases (AMG, Celluclast, Termamyl, Ultraflo, and Viscozyme) and proteases (Alcalase, Flavorzyme, Kojizyme, Neutrase, and Protamex). The scavenging activity of the radicals increased with increased concentrations of the extracts. The scavenging results were higher for hydroxyl and alkyl radicals and lower for DPPH radical as compared with vitamin C as a reference. The hydrogen peroxide scavenging activity of the extracts was also investigated; the Alcalase extract showed the highest scavenging activity among the extracts prepared with the five proteases and five carbohydrates. In addition, the DNA damage was determined by using the comet assay with alkaline electrophoresis and was quantified by measuring the tail length. The preventive effect of Alcalase extract from S. thunbergii against DNA damage increased with increments of concentration of the enzymatic extracts.
    Journal of Agricultural and Food Chemistry 09/2005; 53(17):6666-72. · 2.82 Impact Factor

Institutions

  • 2009–2012
    • Gangneung-Wonju National University
      Wŏnju, Gangwon, South Korea
    • Chonnam National University
      • School of Food Science and Aqualife Medicine
      Yeoju, Gyeonggi, South Korea
  • 2002–2012
    • Pukyong National University
      • • Department of Chemistry
      • • Marine Bioprocess Research Center
      Pusan, Busan, South Korea
  • 2011
    • Silla University
      Pusan, Busan, South Korea
  • 2007
    • Pusan National University
      Pusan, Busan, South Korea
  • 2003
    • Marine Biological Research Institute of Japan Co., Ltd.
      Tokyo, Tokyo-to, Japan