• 동의생리병리학회지
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• 제19권1호
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• pp.234-241
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• 2005

Galla Rhois is a nest of parasitic bug, Mellaphis chinensis Bell, in Rhus chinensis Mill. Galla Rhois has been used for the therapy of diarrhea, peptic ulcer, hemauria, etc., that showed various antiinflammatory activity, and other biological properties. We studied the effect of Galla Rhois water extract(GRWE). The cytotoxic activity of GRWE in HL-60 cells was increased in a concentration-dependent manner. GRWE was cytotoxic to HL-60 cells, with $IC_50$ of $100{\mu}g/m{\ell}$. Treatment of GRWE to HL-60 cells showed the fragmentation of DNA in a concentration manner, suggesting that these cells underwent apoptosis. In addition, the flow cytometric analysis revealed GRWE concentration-dependently increased apoptotic cells with hypodiploid DNA content and arrested G1 phase of cell cycle. These results indicate that GRWE may have a possibility of potential anticancer activities. Treatment of HL-60 cells with GRWE was induced activation of caspase-3, caspase-8 and proteolytic cleavage of poly(ADP-ribose) polymerase. Also, caspase-3 was directly activated via caspase-8 activation. GRWE also caused the release of cytochrome c from mitochondria into the cytosol. GRWE-induced cytochrome c release was mediated by caspase-8-dependent cleavage of Bid and Bax translocation. These results suggest that caspase-8 mediates caspase-3 activation and cytochrome c release during GRWE-induced apoptosis in HL-60 cells.

• Journal of Microbiology and Biotechnology
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• 제24권2호
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• pp.160-167
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• 2014

Oligopeptidase B (OpdB) is a serine peptidase widespread among bacteria and protozoa that has emerged as a virulence factor despite its function has not yet been precisely established. By using an OpdB-overexpressing Escherichia coli strain, we found that the overexpressed peptidase makes the bacterial cells specifically less susceptible to several proline-rich antimicrobial peptides known to penetrate into the bacterial cytosol, and that its level of activity directly correlates with the degree of resistance. We established that E. coli OpdB can efficiently hydrolyze in vitro cationic antimicrobial peptides up to 30 residues in length, even though they contained several prolines, shortening them to inactive fragments. Two consecutive basic residues are a preferred cleavage site for the peptidase. In the case of a single basic residue, there is no cleavage if proline residues are present in the $P_1$ and $P_2$ positions. These results also indicate that cytosolic peptidases may cause resistance to antimicrobial peptides that have an intracellular mechanism of action, such as the proline-rich peptides, and may contribute to define the substrate specificity of the E. coli OpdB.

• Journal of Microbiology and Biotechnology
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• 제16권8호
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• pp.1262-1268
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• 2006

In the search for a novel cytotoxic substance from medicinal plants, HY53 ($C_{17}H_{32}O_2N_2$; molecular weight 296) was isolated from the leaves of Pata de Vaca (Bauhinia forficata). The growth of the HepG2 cells was inhibited in a dose-dependent manner when treated with 0.07 to 0.40 mM HY53 for 24 h (IC$_{50}$: 0.13 mM). Furthermore, nuclear DAPI staining revealed the typical nuclear features of apoptosis in the HepG2 cells exposed to 0.27 mM HY53, whereas a flow cytometric analysis of the HepG2 cells using propidium iodide showed that the apoptotic cell population increased gradually from 8% at 0 mM to 23% at 0.14 mM and 45% at 0.40 mM after being exposed to each concentration of HY53 for 24 h. Moreover, a TUNEL assay also exhibited the apoptotic induction of the HepG2 cells treated with HY53. To obtain further information on the HY53-induced apoptosis, the expression level of certain apoptosis-associated proteins was examined using a Western blot analysis. Treatment of the HepG2 cells with HY53 resulted in the activation of caspase-3, and subsequent proteolytic cleavage of poly(ADP-ribose) polymerase (PARP). Consequently, the results confirmed that the apoptosis in the HepG2 cells was induced by HY53 and the involvement of caspase-3-mediated PARP cleavage in the apoptotic process.

• Journal of Microbiology and Biotechnology
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• 제16권9호
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• pp.1399-1404
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• 2006

The roots of Aralia continentalis (AC) have been used traditionally in Korean as a folk medicine for anti-inflammation and as an anti-rheumatic. In this study, we report that the ethyl acetate-soluble traction (ACE) of the methanolic extract of AC root inhibited the cell growth of various human cancer cell lines and induced apoptosis of HL-60, human promyelocytic leukemia cells. Its $IC_{50}$ values on growth inhibition were estimated to be $56.3{\mu}g/ml$ on HL-60, $87.2{\mu}g/ml$ on HepG2, $93.2{\mu}g/ml$ on HeLa, $135.5{\mu}g/ml$ on DU-145, and $135.8{\mu}g/ml$ on HT-29 cells. Interestingly, ACE showed no antiproliferative effect on normal lymphocyte cells used as control. Furthermore, nuclear DAPI staining revealed the typical nuclear features of apoptosis in the HL-60 cells exposed to $80{\mu}g/ml$ ACE, and a flow cytometric analysis of the HL-60 cells using propidium iodide showed that the apoptotic cell population increased gradually from 5% at 0 h to 16% at 12 h and 20% at 24 h after treated with $50{\mu}g/ml$ of ACE. TUNEL assay also revealed the apoptotic induction of the HL-60 cells treated with ACE. To obtain further information on the ACE-induced apoptosis, the expression level of certain apoptosis-associated proteins was examined using a Western blot analysis. Treatment of the HL-60 cells with ACE resulted in the activation of caspase-3, and subsequent proteolytic cleavage of poly(ADP-ribose) polymerase (PARP). The above results confirmed that the apoptosis in the HL-60 cells was induced by ACE, and that caspase-3-mediated PARP cleavage was involved in the process.

• The Korean Journal of Physiology and Pharmacology
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• 제17권3호
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• pp.189-195
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• 2013

Amyloid-${\beta}$ peptide ($A{\beta}$), generated by proteolytic cleavage of the amyloid precursor protein (APP), plays a pivotal role in the pathogenesis of Alzheimer's disease (AD). The key step in the generation of $A{\beta}$ is cleavage of APP by beta-site APP-cleaving enzyme 1 (BACE1). Levels of BACE1 are increased in vulnerable regions of the AD brain, but the underlying mechanism is unknown. In the present study, we reported the effects of ferrous ions at subtoxic concentrations on the mRNA levels of BACE1 and a-disintegrin-and-metalloproteinase 10 (ADAM10) in PC12 cells and the cell responses to ferrous ions. The cell survival in PC12 cells significantly decreased with 0 to 0.3 mM $FeCl_2$, with 0.6 mM $FeCl_2$ treatment resulting in significant reductions by about 75%. 4,6-diamidino-2-phenylindole (DAPI) staining showed that the nuclei appeared fragmented in 0.2 and 0.3 mM $FeCl_2$. APP-${\alpha}$-carboxyl terminal fragment (APP-${\alpha}$-CTF) associations with ADAM10 and APP-${\beta}$-CTF with BACE1 were increased. Levels of ADAM10 and BACE1 mRNA increased in response to the concentrations of 0.25 mM, respectively. In addition, p-ERK and p-Bad (S112, S155) expressions were increased, suggesting that APP-CTF formation is related to ADAM10/ BACE1 expression. Levels of Bcl-2 protein were increased, but significant changes were not observed in the expression of Bax. These data suggest that ion-induced enhanced expression of AMDA10/BACE1 could be one of the causes for APP-${\alpha}/{\beta}$-CTF activation.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 2001년도 Proceedings of 2001 International Symposium
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• pp.40-45
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• 2001

Raw starch-digesting amylase (BF-2A, M.W. 93, 000 Da) from Bacillus circulans F-2 was converted to two components during digestion with subtilisin. Two components were separated and designated as BF-2A' (63, 000 Da) and BF-2B (30, 000 Da), respectively. BF-2A' exhibited the same hydrolysis curve for soluble starch as the original amylase (BF-2A). Moreover, the catalytic activities of original and modified enzymes were indistinguishable in $K_{m}$, Vmax for, and in their specific activity for soluble starch hydrolysis. However, its adsorbability and digestibility on raw starch was greatly decreased. Furthermore, the enzymatic action pattern on soluble starch was greatly different from that of the BF-2A. A smaller peptide (BF-2B) showed adsorb ability onto raw starch. By these results, it is suggested that the larger peptide (BF-2A') has a region responsible for the expression of the enzyme activity to hydrolyze soluble substrate, and the smaller peptide (BF-2B) plays a role on raw starch adsorption. A similar phenomenon is observed during limited proteinase K, thermolysin, and endopeptidase Glu-C proteolysis of the enzyme. Fragments resulting from proteolysis were characterized by immunoblotting with anti-RSDA. The proteolytic patterns resulting from proteinase K and subtilisin were the same, producing 63- and 30-kDa fragments. Similar patterns were obtained with endopeptidase Glu-C or thermolysin. All proteolytic digests contained a common, major 63-kDa fragment. Inactivation of RSDA activity results from splitting off the C-terminal domain. Hence, it seems probable that the protease sensitive locus is in a hinge region susceptible to cleavage. Extracellular enzymes immunoreactive toward anti-RSDA were detected through whole bacterial cultivation. Proteins of sizes 93-, 75-, 63-, 55-, 38-, and 31-kDa were immunologically identical to RSDA. Of these, the 75-kDa and 63-kDa proteins correspond to the major products of proteolysis with Glu-C and thermolysin. These results postulated that enzyme heterogeneity of the raw starch-hydrolysis system might arise from the endogeneous proteolytic activity of the bacterium. Truncated forms of rsda, in which the gene sequence encoding the conserved domain had been deleted, directed the synthesis of a functional amylase that did not bind to raw starch. This indicates that the conserved region of RSDA constitutes a raw starch-binding domain, which is distinct from the active centre. The possible role of this substrate-binding region is discussed.d.

• 한국수산과학회지
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• 제42권2호
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• pp.139-145
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• 2009

We cloned and sequenced the open reading frame (ORF) cDNA encoding myostatin from the muscle of abalone (Haliotis discus hannai). The ORF cDNA of the abalone myostatin is 1134 bp and encoded 377 amino acid residues that were 60-96% homologous with the amino acids of other organism myostatins. In addition, the ORF contained a conserved proteolytic cleavage site (RXRR) and nine conserved cysteine residues in the C-terminus. Semi-quantitative RT-PCR revealed the presence of myostatin mRNA in various tissues. The strongest expression was observed in the mantle of female abalone, and the gills and heart of male abalone.

• BMB Reports
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• 제48권5호
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• pp.277-282
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• 2015

We demonstrated previously that a disintegrin and metalloproteinase 15 (ADAM15) is released into the extracellular space as an exosomal component, and that ADAM15-rich exosomes have tumor suppressive functions. However, the suppressive mechanism of ADAM15-rich exosomes remains unclear. In this study, we show that the ADAM15 ectodomain is cleaved from released exosomes. This shedding process of the ADAM15 ectodomain was dramatically enhanced in conditioned ovarian cancer cell medium. Proteolytic cleavage was completely blocked by phenylmethylsulfonyl fluoride, indicating that a serine protease is responsible for exosomal ADAM15 shedding. Experimental evidence indicates that the ADAM15 ectodomain itself has comparable functions with those of ADAM15-rich exosomes, which effectively inhibit vitronectininduced cancer cell migration and activation of the MEK/extracellular regulated kinase signaling pathway. We present a tumor suppressive mechanism for ADAM15 exosomes and provide insight into the functional significance of exosomes that generate tumor-inhibitory factors. [BMB Reports 2015; 48(5): 277-282]

• Bulletin of the Korean Chemical Society
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• 제33권9호
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• pp.3048-3054
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• 2012

The use of aspirin is widely recommended for the prevention of heart attacks owing to its ability to inhibit platelet activation by irreversibly blocking cyclooxygenase 1. However, aspirin also affects the fibrinolytic and hemostatic pathways by mechanisms that are not well understood, causing severe hemorrhagic complications. Here, we investigated the ability of aspirin and aspirin metabolites to inhibit thrombin-activatable fibrinolysis inhibitor (TAFI), the major inhibitor of plasma fibrinolysis. TAFI is activated via proteolytic cleavage by the thrombin-thrombomodulin complex to TAFIa, a carboxypeptidase B-like enzyme. TAFIa modulates fibrinolysis by removing the C-terminal arginine and lysine residues from partially degraded fibrin, which in turn inhibits the binding of plasminogen to fibrin clots. Aspirin and its major metabolites, salicylic acid, gentisic acid, and salicyluric acid, inhibit TAFIa carboxypeptidase activity. Salicyluric acid effectively blocks activation of TAFI by thrombin-thrombomodulin; however, salicylates do not inhibit carboxypeptidase N or pancreatic carboxypeptidase B. Aspirin and other salicylates accelerated the dissolution of fibrin clots and reduced thrombus formation in an in vitro model of fibrinolysis. Inhibition of TAFI represents a novel hemostatic mechanism that contributes to aspirin's therapy-associated antithrombotic activity and hemorrhagic complications.

• Preventive Nutrition and Food Science
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• 제5권3호
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• pp.170-173
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• 2000

The inhibitory effect of extracts from 15 edible plants on the protease of human immunodeficiency virus (HIV) type 1 was investigated. Protease activity was determined by incubating the extracts in a reaction mixture containing protease and substrate His-Lys-Ala-Arg-Val-Leu-(p-NO$_2$-Phe)-Glu-Ala-Nle-Ser-NH$_2$ to inhibit proteolytic cleavage. Of various plants tested, the leaves of Cedrela sinensis inhibited the HIV-1 protease by 42% at a concentration of 100$\mu\textrm{g}$/ml. A major flavonoid isolated from the leaves of C. sinensis, quercetin 3-O-$\alpha$-L-rhamnoside showed inhibitory activity of 19% at a concentration of 100$\mu$M.