• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.5
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• pp.721-726
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• 2012

Lactic acid bacteria (LAB) are able to secrete antimicrobial peptides called bacteriocins, which inhibit other bacteria such as pathogenic microorganisms. Therefore, bacteriocin-producing starters can be used as natural biopreservatives for various foods. The objective of this study was to screen and characterize bacteriocin-producing LAB from Kimchi and to investigate their applicability as a starter in Kimchi fermentation. To screen bacteriocin-producing LAB, gram-positive and gram-negative bacteria were used as indicators. To measure the antimicrobial activities of isolates, agar well diffusion assay method was used. According to the results, bacteriocin produced by $Lb.$ $sakei$ B16 showed antimicrobial activity against $Listeria$ $monocytogenes$ ATCC 19115, $Escherichia$ $coli$ KCTC 1467, and$Lactobacillus$ $plantarum$ KTCT 3104. Furthermore, bacteriocin was very stable after treatment with high temperature and high and low pH, but its effects were inhibited by treatment with proteolytic enzymes such as trypsin, proteinase K, and ${\alpha}$-chymotrypsin, revealing their bacteriocin-like protein- based structure. These results suggest that $Lb.$ $sakei$ B16 and its bacteriocin are good candidates as a functional probiotic and natural biopreservative, respectively, in fermented foods.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.311-318
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• 2002

A new bacteriocin producing lactic acid bacteria having antagonistic activity against Lactobacillus plantarum, was isolated from Kimchi. It was identified as Leuconostoc mesenteroides, and designated as Leuconostoc mesenteroides B7. The bacteriocin from Leuconostoc mesenteroides B7 named as bacteriocin B7 was stable in the pH range $2.5{\sim}9.5$. Bacteriocin B7 was active over a wide temperature range from $4^{\circ}C$ to $120^{\circ}C$. It was inactivated by proteinase K, trypsin, ${\alpha}-chymotrypsin$, and protease treatments indicating its proteinous nature. Tricine-SDS-PAGE of the purified bacteriocin B7 showed the presence of a single band, having a molecular mass of about 3,500 dalton. Mixed culture of the producer and the indicator, Lb. plantarum KFRI 464 or Lb. delbruekii KFRI 347, increased production of bacteriocin B7. This result suggested the presence of bacteriocin inducing factor in the indicator strain. The inducing factor was localized in cell debris and intracellular faction of the indicator cell, Lb. plantarum KFRI 464. Treatment of the inducing factor with proteinase K destroyed inducing activity. This result strongly suggested that the inducing factor is a protein.

• Microbiology and Biotechnology Letters
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• v.15 no.2
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• pp.129-134
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• 1987

Aspergillus sp. (MK-24) producing a biological active substance that inhibited the venom proteinase activity was isolated from soil. The substance also inhibited the activity of trypsin and coagulation of blood, but did not inhibit papain, $\alpha$-chymotrypsin and pepsin. The substance was partially purified from culture filtrate by precipitaion with acetone, and by chromatography of DEAE-Sepadex A-50 column and Amberlite IRC-50 ion exchange. The inhibitory substance was stable in the wide pH range from 2.0 to 12.0 at 37$^{\circ}C$, but not stable at $65^{\circ}C$ in the alkaline pH. Only 12% of the activity was decreased by the heat treatment at 10$0^{\circ}C$ for two hours. The inhibition on venom proteinase (Agkistrodon bromohoffi brevicaudus) was a mixed type. The inhibitory activity depended on the preincubation time and completely depressed by cupric, zinc and cobalt ions. The inhibition on the venom proteinase was appeared strongly on casein but not on ovalbumin or hemoglobin as a substrate.

• Korean Journal of Veterinary Research
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• v.35 no.3
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• pp.447-458
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• 1995

This study was carried out to characterize nonadrenergic, noncholinergic(NANC) relaxation of porcine retractor penis(PRP) muscle induced by electrical field stimulation(EFS) and to investigate the actions of niric oxide(NO) and vasoactive intestinal polypeptide(VIP) as candidates for NANC neurotransmitters. Biphasic relaxations of PRP muscle were induced by EFS to NANC nerve. Rapid-phase relaxation was observed at low frequency(0.5-16Hz) and slow-phase relaxation followed during high frequency(8-60Hz). Both relaxations were frequency-dependent and TTX($1{\times}10^{-6}M$)-sensitive. L-NAME($2{\times}10^{-5}M$) inhibited the rapid-phase relaxation, but not the slow-phase relaxation. The inhibition of the rapid-phase relaxation with L-NAME was reversed by L-arginine ($1{\times}10^{-3}M$) but not by D-arginine($1{\times}10^{-3}M$). Methylene blue($4{\times}10^{-5}M$) reduced the rapid-phase relaxation. Exogenous No(ExoNO, $1{\times}10^{-5}-1{\times}10^{-4}M$) induced dose-dependent relaxations of PRP muscle. Oxyhemoglobin($5{\times}1^{-5}M$) blocked the relaxation induced by ExoNO and inhibited EFS-induced relaxation. Hydroquinone($1{\times}10^{-4}M$) also abolished the relaxation induced by ExoNO, but did not affect EFS-induced relaxation. L-NAME resistant slow-phase relaxation to EFS was inhibited by ${\alpha}$-chymotrypsin(2.5 U/ml). Both methylene blue($4{\times}10^{-5}M$) and Nethylmaleimide($1{\times}10^{-4}M$) reduced the slow-phase relaxation by EFS. [4-Cl-D-$Phe^6$, $Leu^{17}$]-VIP($3{\times}10^{-6}M$) inhibited the slow-phase relaxation by EFS. External applications of VIP ($1{\times}10^{-7}M$) caused relaxations that were simillar to the L-NAME resistant slow-phase relaxations induced by EFS, and relaxant effects of exogenous VIP were blocked by ${\alpha}$-chymotrypsin(2.5 U/ml).

• Journal of Life Science
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• v.23 no.11
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• pp.1404-1408
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• 2013

(-)-Epigallocatechin-3-gallate (EGCG), a green tea polyphenol, has been shown to have strong antibacterial, antiviral, antioxidant, anti-inflammatory, and chemopreventive effects. However it is unknown whether EGCG can recover alcohol-associated pancreatitis. The aim of this study was to investigate the effects of EGCG on pancreatic enzyme activities and the expressions of pancreatic regenerating related markers, such as adenosine monophosphate-activated protein kinase (AMPK), raf-1 kinase inhibitor protein (RKIP), and Regenerating gene 1 (Reg1), in mice pancreatic primary acinar cells. Our results revealed that activities of ${\alpha}$-amylase and chymotrypsin were significantly increased in the cells treated with ethanol compared to the untreated control cells; however, the increased activities of both enzymes were markedly reduced by pretreatment with EGCG. Phosphorylation of AMPK and total expression of RKIP were decreased in the ethanol-treated primary acinar cells; however, these were both significantly increased in the EGCG-pretreated cells. In addition, when EGCG was treated, expression of Reg1 was markedly increased compared with that of the control or the ethanol-treated primary acinar cells, demonstrating that EGCG can modulate pancreatic regenerating related genes. Therefore, our findings suggest that EGCG may have therapeutic utility in the prevention or treatment of alcohol-associated pancreatitis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.2
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• pp.127-134
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• 2018

Arteriosclerosis is the major cause of coronary artery and cerebrovascular disease, which are leading causes of death. Pro-inflammatory cytokines induce injury to vascular endothelial cells by increasing cell adhesion molecules, leading to vascular inflammation, a major risk factor for the development of arteriosclerosis. In the current study, we investigated the inhibitory effect of enzymatic hydrolysate from Japanese mud shrimp Upogebia major on the inflammation of tumor necrosis $factor-{\alpha}$ ($TNF-{\alpha}$)-stimulated human umbilical vein endothelial cells (HUVECs). We first evaluated the antioxidant and angiotensin I-converting enzyme (ACE) inhibitory activities of eight U. major enzymatic hydrolysates: alcalase, papain, ${\alpha}$-chymotrypsin (${\alpha}-Chy$), trypsin, pepsin, neutrase, protamex and flavourzyme. Of these, ${\alpha}-Chy$ exhibited potent antioxidant and ACE inhibitory activities. The ${\alpha}-Chy$ hydrolysate was fractionated by two ultrafiltration membranes of 3 and 10 kDa. The ${\alpha}-Chy$ hydrolysate of U. major and its molecular weight cut-off fractions resulted in a significant reduction in NO production and a decrease in cell adhesion molecules [vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1) and endothelial-selectin (E-selectin)] and pro-inflammatory cytokines [interleukin-6 (IL-6), interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1)] in $TNF-{\alpha}$-stimulated HUVECs. These results suggest that enzymatic hydrolysate from U. major can be used in the control and prevention of vascular inflammation and arteriosclerosis.

• Food Science of Animal Resources
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• v.37 no.1
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• pp.62-70
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• 2017

The aim of this study was identifying a suitable food grade enzymes to hydrolyze whey protein concentrates (WPCs), to give the highest bioactivity. WPCs from ultrafiltration retentate were adjusted to 35% protein (WPC-35) and hydrolyzed by enzymes, alcalase, ${\alpha}-chymotrypsin$, pepsin, protease M, protease S, and trypsin at different hydrolysis times (0, 0.5, 1, 2, 3, 4, and 5 h). These 36 types of hydrolysates were analyzed for their prominent peptides ${\beta}-lactoglobulin$ (${\beta}-Lg$) and ${\alpha}-lactalbumin$ (${\alpha}-La$), to identify the proteolytic activity of each enzyme. Protease S showed the highest proteolytic activity and angiotensin converting enzyme inhibitory activity of IC50, 0.099 mg/mL (91.55%) while trypsin showed the weakest effect. Antihypertensive and antioxidative peptides associated with ${\beta}-Lg$ hydrolysates were identified in WPC-35 hydrolysates (WPH-35) that hydrolyzed by the enzymes, trypsin and protease S. WPH-35 treated with protease S in 0.5 h, responded positively to usage as a bioactive component in different applications of pharmaceutical or related industries.

• The Korean Journal of Zoology
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• v.33 no.1
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• pp.53-62
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• 1990

Fully grown amphibian oocytes undergo their maturation (germinal vesicle breakdown, GVBD) during in vitro follicle culture when they are stimulated with frog pituitary homogenate (FPH) or progesterone. Present experiments were designed to determine whether proteolytic enzymes are involved in the regulation of the matunation process. Treatment of a $\alpha$ -chymoiyypsin inhibitor, N a -tosyl-L-phenylalanine-chloromethyl-ketone(TP) to the oocytes exhibited a biphasic phenomenon, the induction of the maturation without added hormone at relatively low doses (0.001-1 $\mu$M) and inhibition of the hormone induced oocyte maturation at a high dose (100 $\mu$M). Treatment of a trypsin inhibitor, N a -tosyl-L-lysine-chloromethyl ketone(TLCK) to the oocytes did not induce the maturation, but rather suppressed the hormone induced oocyte maturation in a high dose(100 $\mu$ M). Treatment of exogenous iyypsin to the oocyte induced their maturation without added hormone in a dose dependent manner (0.001-1 $\mu$ M). The data presented here indicate that some proteolytic enzymes play a role in the regulation of the maturation(meiotic arrest or reinitiation) in amphibians.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.489-494
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• 2008

In order to develop a potent antidementia $\beta$-secretase inhibitor from phytochemicals, $\beta$-secretase inhibitory activities of extracts from many medicinal plants and herbs were determined. Water extracts from Rubus coreanus showed the highest $\beta$-secretase inhibitory activity of 84.5%. After purification of the $\beta$-secretase inhibitor from R. coreanus using systematic solvent extraction, ultrafiltration, Sephadex G-10 column chromatography, and reverse-phase high performance liquid chromatography (HPLC), a purified $\beta$-secretase inhibitor with $IC_{50}$ inhibitory activity of $6.3{\times}10^3\;ng/mL$ ($1.56{\times}10^{-6}\;M)$ was obtained with a 0.08% solid yield. The molecular mass of the purified $\beta$-secretase inhibitor was estimated to be 576 Da by liquid chromatography-mass spectrometry (LC-MS) and $\beta$-secretase inhibitor also is a new tetrapeptide with the sequence Gly-Trp-Trp-Glu. The purified $\beta$-secretase inhibitory peptide inhibited $\beta$-secretase non-competitively and also show less inhibition on trypsin, however no inhibition on other proteases such as $\alpha$-secretase, chymotrypsin, and elastase.

• Journal of Marine Bioscience and Biotechnology
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• v.7 no.1
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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.