• 제목/요약/키워드: size exclusion

검색결과 245건 처리시간 0.039초

Molecular Cloning and Enzymatic Characterization of Cyclomaltodextrinase from Hyperthermophilic Archaeon Thermococcus sp. CL1

  • Lee, Jae-Eun;Kim, In-Hwan;Jung, Jong-Hyun;Seo, Dong-Ho;Kang, Sung-Gyun;Holden, James F.;Cha, Jaeho;Park, Cheon-Seok
    • Journal of Microbiology and Biotechnology
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    • 제23권8호
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    • pp.1060-1069
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    • 2013
  • Genome organization near cyclomaltodextrinases (CDases) was analyzed and compared for four different hyperthermophilic archaea: Thermococcus, Pyrococcus, Staphylothermus, and Thermofilum. A gene (CL1_0884) encoding a putative CDase from Thermococcus sp. CL1 (tccd) was cloned and expressed in Escherichia coli. TcCD was confirmed to be highly thermostable, with optimal activity at $85^{\circ}C$. The melting temperature of TcCD was determined to be $93^{\circ}C$ by both differential scanning calorimetry and differential scanning fluorimetry. A size-exclusion chromatography experiment showed that TcCD exists as a monomer. TcCD preferentially hydrolyzed ${\alpha}$-cyclodextrin (${\alpha}$-CD), and at the initial stage catalyzed a ring-opening reaction by cleaving one ${\alpha}$-1,4-glycosidic linkage of the CD ring to produce the corresponding single maltooligosaccharide. Furthermore, TcCD could hydrolyze branched CDs (G1-${\alpha}$-CD, G1-${\beta}$-CD, and G2-${\beta}$-CD) to yield significant amounts (45%, 40%, and 46%) of isomaltooligosaccharides (panose and $6^2$-${\alpha}$-maltosylmaltose) in addition to glucose and maltose. This enzyme is one of the most thermostable maltogenic amylases reported, and might be of potential value in the production of isomaltooligosaccharides in the food industry.

폴리락티드-글리콜리드 마이크로스피어에 봉입된 단백질의 항원성 평가 (Antigenicity of Protein Entrapped in Poly(lactide-co-glycolide) Microspheres)

  • 송세현;조성완;신택환;윤미경;최영욱
    • Journal of Pharmaceutical Investigation
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    • 제31권3호
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    • pp.191-196
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    • 2001
  • Biodegradable polymeric microspheres were studied for their usefulness as carriers for the delivery of vaccine antigens. However, protein antigen could be denatured during microencapsulation processes due to the exposure to the organic phase and stress condition of cavitation and shear force. Therefore this study was carried out to re-evaluate the degree of protein denaturation during microencapsulation with poly(lactide-co-glycolide) (PLGA) copolymer. PLGA microspheres containing ovalbumin (OVA), prepared by W/O/W multiple emulsification method, were suspended in pH 7.4 PBS and incubated with shaking at $37.5^{\circ}C$. Drug released medium was collected periodically and analyzed for protein contents by micro-BCA protein assay. In order to evaluate the protein integrity, release medium was subjected to the analyses of SDS-PAGE and size exclusion chromatography (SEC). And enzyme-linked immunosorbent assay (ELISA) was introduced to measure the immunoreactivity of entrapped OVA and to get an insight into the three-dimensional structure of epitope. The structures of entrapped protein were not affected significantly by the results of SDS-PAGE and SEC. However, immunoreactivity of released antigen was varied, revealing the possibility of protein denaturation in some microspheres when it was evaluate by ELISA method. Therefore, in order to express the degree of protein denaturation, antigenicity ratio (AR) was obtained as follows: amount of immunoreactivity of OVA/total amount of OVA released ${\times}100(%)$. ELISA method was an efficient tool to detect a protein denaturation during microencapsulation and the comparison of AR values resulted in more accurate evaluation for immunoreactivity of entrapped protein.

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Which is the Best Chinese Herb Injection Based on the FOLFOX Regimen for Gastric Cancer? A Network Meta-analysis of Randomized Controlled Trials

  • Wang, Jian-Cheng;Tian, Jin-Hui;Ge, Long;Gan, Yu-Hong;Yang, Ke-Hu
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권12호
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    • pp.4795-4800
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    • 2014
  • Background: Few studies have directly compared clinical efficacy and safety among Chinese herb injections (CHIs) for gastric cancer (GC). The present study aimed to compare CHIs combined with FOLFOX regimens for GC to show which provides the best CHIs results. Materials and Methods: 9 electronic databases and 6 gray literature databases were comprehensive searched in April 20, 2013. According to inclusion and exclusion criteria, two reviewers independently selected and assessed the included trials. The risk of bias tool described in the Cochrane Handbook version 5.1.0 and CONSORT statement were used to assess the quality of the trials. All calculations and graphs were performed and produced using ADDIS 1.16.5 software. Results: A total of 541 records were searched and 38 RCTs met the inclusion criteria (2,761 participants), involving 10 CHIs. The results of network meta-analysis showed that compared with FOLFOX alone, combinations with Kanglaite, Astragalus polysaccharides, Cinobufacini, or Yadanziyouru injections could furthest strengthen ORR, improve the quality of life, reduce nausea and vomiting, and reduce the incidence of leukopenia (III-IV). Conclusions: Kanglaite injection, Astragalus polysaccharides injection, Yadanziyouru injection were superior to other CHIs in clinical efficacy and safety for GC. The conclusions now need to be confirmed by large sample size direct head-to-head studies.

Identification of Lys49-PLA2 from crude venom of Crotalus atrox as a human neutrophil-calcium modulating protein

  • Sultan, Md. Tipu;Li, Hong-Mei;Lee, Yong Zu;Lim, Soon Sung;Song, Dong-Keun
    • The Korean Journal of Physiology and Pharmacology
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    • 제20권2호
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    • pp.177-183
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    • 2016
  • We fortuitously observed a human neutrophil intracellular free-calcium concentration ($[Ca^{2+}]_i$) increasing activity in the commercially available phosphodiesterase I (PDE I), which is actually dried crude venom of Crotalus atrox. As this activity was not observed with another commercially available pure PDE I, we tried to find out the causative molecule(s) present in 'crude' PDE, and identified Lys49-phospholipase A2 (Lys49-PLA2 or K49-PLA2), a catalytically inactive protein which belongs to the phospholipase A2 family, by activity-driven three HPLC (reverse phase, size exclusion, reverse phase) steps followed by SDS-PAGE and LC-MS/MS. K49-PLA2 induced $Ca^{2+}$ influx in human neutrophils without any cytotoxic effect. Two calcium channel inhibitors, 2-aminoetoxydiphenyl borate (2-APB) ($30{\mu}M$) and SKF-96365 ($20{\mu}M$) significantly inhibited K49-PLA2-induced $[Ca^{2+}]_i$ increase. These results suggest that K49-PLA2 modulates $[Ca^{2+}]_i$ in human neutrophils via 2-APB- and SKF-96365-sensitive calcium channels without causing membrane disruption.

어류 알로부터 Protease Inhibitors의 크로마토그래피법에 의한 분획 (Chromatographic Fractionation of Protease Inhibitors from Fish Eggs)

  • 김진수;김기현;김현정;김민지;박성환;이현지;허민수
    • 한국수산과학회지
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    • 제46권4호
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    • pp.351-358
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    • 2013
  • A protease inhibitor from fish eggs was fractionated using chromatographic methods. The fractionation efficiency was evaluated in terms of specific inhibitory activity (SIA, U/mg), purity (fold), total inhibitory activity (TIA, U), and recovery (%). The protease inhibitor (PI) from egg extracts of skipjack tuna (ST Katsuwonus pelamis), yellowfin tuna (YT Thunnus albacares) and Alaska pollock (AP Theragra chalcogramma) was fractionated using Sephadex G-50 gel filtration and DEAE-Sepharose CL-6B anion exchange chromatography based on protein size exclusion and net charge, respectively. Fractions exhibiting strong inhibitory activity were contained in the 30-50 kDa fraction on gel filtration and in the range of 0.4-0.7 M NaCl gradient fraction on anion exchange chromatography. The respective TIA and percent recovery of the fraction obtained with gel filtration toward trypsin and $N{\alpha}$-benzoyl-L-arginine-p-nitroanilide (BAPNA) were 2,758.7 U and 29.6% for ST, 1,005.5 U and 25.6% for YT, and 1,267.5 U and 26.0% for AP. Gel filtration chromatography was more effective at fractionating PI than using ion exchange chromatography. These results suggest that fish eggs act as serine protease inhibitors and might be useful for protease inhibition in foodstuffs.

Production and Characterization of Acid-stable Pectin Lyase from Bacillus sp. PN33

  • Kim, Jong-Chon;Kim, Hwa-Young;Choi, Yong-Jin
    • Journal of Microbiology and Biotechnology
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    • 제8권4호
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    • pp.353-360
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    • 1998
  • A bacterial strain PN33 producing large amounts of extracellular pectin lyase (PNL, EC 4.2.2.10) was isolated from soil. The isolated bacterium was identified as a strain of Bacillus sp. Production of PNL by the strain was induced only by pectins, with a higher degree of esterification, which had been added to the culture medium as a sole carbon source. The optimal medium for PNL production was determined to consist of 10 g pectin, 2 g yeast extract, 4 g $K_2HPO_4{\cdot}3H_2O$, 0.6 g $MgSO_4$, and 0.11 g $CaCl_2$ per liter (pH 7.0). The PNL activity in the culture supernatant reached the highest level of 132 mU/ml after 32 h cultivation at $37^{\circ}C$ in the optimal medium. The PNL produced was purified to homogeneity by ammonium sulfate fractionation (50~80%), and cation exchange and size exclusion chromatographies. The molecular mass of the enzyme was estimated to be approximately 52 kDa by SDS-PAGE. Almost the same mass was determined by nondenaturing PAGE, indicating that the functional enzyme had a monomeric structure. As expected, the PNL exhibited higher activities on the highly esterified pectins whereas it gave no detectable activity on polygalacturonic acid. The enzyme showed the highest activity at the acidic pH of 6.0, exceptional for a bacterial PNL. Maximum activity was measured at $40^{\circ}C$, although the stability f the purified enzyme was poor at this temperature. alcium (1 mM) was found to activate the PNL activity by $50\%$, and also remarkably increased the thermal stability f the enzyme. Phenylmethylsulfonylfluoride (PMSF) and iethylpyrocarbonate (DEPC) inhibited the PNL activity lmost completely at the concentration of 5 mM. This result ndicates that some serine and histidine residues of the nzyme may play an essential role for catalytic function of he enzyme.

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An Efficient Method for Synthesis of PEO-Based Macromonomer and Macroinitiator

  • Kim, Jung-Ahn;Choi, Song-Yee;Kim, Kyung-Min;Go, Da-Hyeon;Jeon, Hee-Jeong;Lee, Jae-Yeol;Park, Hyeong-Soo;Lee, Cheol-Han;Park, Heung-Mok
    • Macromolecular Research
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    • 제15권4호
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    • pp.337-342
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    • 2007
  • The n-butyllithium-initiated ring-opening polymerization of ethylene oxide, in a mixture of benzene and dimethylsulfoxide (DMSO), between $25-45^{\circ}C$, with potassium tert-butoxide, is a useful and powerful method to control the molecular weight as well as achieve a quantitative chain-end functionalization yield of the resulting polymeric alkoxide via a one pot synthesis. The molecular weight of the product could be controlled by adjusting the ratio of grams of monomer to moles of initiators, such as n-butyllithium ([n-BuLi]) and potassium t-butoxide ([t-BuOK]). The yields for the macromonomer and ${\omega}-brominated$ poly(ethylene oxide) (PEO) were quantitative in relation to the chain-end functionalizations of the polymeric alkoxide formed. The resulting products were characterized by a combination of $^1H-NMR$ spectroscopic and size exclusion chromatographic analyses.

인삼다당체 진산과 유사구조 다당체의 면역증강활성작용 (Comparison between Immunostimulatory Activity and Molecular Structure of Different Polysaccharides)

  • 심지영;정인성;김찬화;윤연숙;송지영
    • IMMUNE NETWORK
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    • 제4권2호
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    • pp.94-99
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    • 2004
  • Background: We previously reported that ginsan, a polysaccharide extracted from Panax ginseng had an immunostimulatory activity such as mitogenic activity, activation of macrophages and killer cells, and production of a variety of cytokines which resulted in antitumor and antiseptic effects. We further purified $\alpha$-(1$\longrightarrow$6)-glucan and $\beta$-(2$\longrightarrow$6)-fructan from the ginsan with size exclusion and ion-exchange column chromatography successively. In this study, we performed the structure-based activity of ginsan by comparison with known polysacchrides such as $\beta$-glucan, curdlan, laminarin, levan, dextran, lentinan and OK-432. Methods: To investigate the immunostimulatory activity of several polysaccharide compounds, we investigated the stimulation of lymphocytes proliferation, the generation of activated killer cells and the secretion of nitrites from activated macrophages. Results: Of polysaccharides tested, curdlan and ginsan stimulated lymphocyte proliferation, suggesting that the molecular weight and composition of polysaccharide are dependent on the mitogenic activity. The production of nitric oxide was significantly increased in curdlan, levan, ginsan and its fraction, indicating that fructan has also capacity to activate macrophages and may devote to kill pathogens. In addition, the activation of macrophages was seemed to be independent of molecular weight of polysaccharide. The generation of AK cells was exhibited in order of curdlan, OK-432> F1, ginsan, F3> levan> etc. The AK activity may be dependent on molecular weight and composition of polysaccharides. Conclusion: Unfortunately, purified polysaccharide from ginsan were less active on immunostimulatory activity than mixed compounds of polysaccharides. From the viewpoint of structure and activity relationships, we found several characteristic features.

A Growth-Stimulating Protein in Cow's Milk

  • Ki, Eun-Kyung;Park, Yong-Bok;Choi, Myung-Sook
    • 동아시아식생활학회지
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    • 제4권3호
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    • pp.59-65
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    • 1994
  • 이 실험에서는 소의 유즙에 있는 성장인자를 세포배양을 통해 확인하고 크로마토그래피를 사용하여 분리 정제하였다. 5%의 우유를 포함하는 배지를 FBS(fetal bovine serum)를 포함한 배지와 비교했을때 Africal green monkey kidney cell의 성장 촉진 효과가 비슷하게 나타났으며, 우유의 성장인자를 분리 정제한 결과 FBS배지에서보다 2,000배 이상의 성장 촉진 효과가 나타났다. 이 성장인자는 hydrophobic column(phenyl-sepharose)과 gel-filtration column(sephadex G-100)을 사용하여 분리했으며 그 결과 milk-deriven growth factor는 phenyl-sepharose에서 50% ethylene glycol step에서 용출되므로 hydrophobic protein임이 증명되었고 size exclusion column chromatography로 부터 분자량이 100,000-15,0000 범위의 고분자 물질임이 밝혀졌다. 또한 우유의 성장인자는 매우 다양하며 그중 본 실험으로부터 정제된 물질이 주요 성장인자로 밝혀졌다.

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Recent advances in the characterization and the treatment methods of effluent organic matter

  • Ray, Schindra Kumar;Truong, Hai Bang;Arshad, Zeshan;Shin, Hyun Sang;Hur, Jin
    • Membrane and Water Treatment
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    • 제11권4호
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    • pp.257-274
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    • 2020
  • There are many previous review articles are available to summarize either the characterization methods of effluent organic matter (EfOM) or the individual control treatment options. However, there has been no attempt made to compare in parallel the physicochemical treatment options that target the removal of EfOM from biological treatments. This review deals with the recent progress on the characterization of EfOM and the novel technologies developed for EfOM treatment. Based on the publications after 2010, the advantages and the limitations of several popularly used analytical tools are discussed for EfOM characterization, which include UV-visible and fluorescence spectroscopy, Fourier transform infrared spectroscopy (FTIR), size exclusion chromatography (SEC), and Fourier transform-ion cyclotron resonance-mass spectrometry (FT-ICR-MS). It is a recent trend to combine an SEC system with various types of detectors, because it can successfully track the chemical/functional composition of EfOM, which varies across a continuum of different molecular sizes. FT-ICR-MS is the most powerful tool to detect EfOM at molecular levels. However, it is noted that this method has rarely been utilized to understand the changes of EfOM in pre-treatment or post-treatment systems. Although membrane filtration is still the preferred method to treat EfOM before its discharge due to its high separation selectivity, the minimum requirements for additional chemicals, the ease of scaling up, and the continuous operation, recent advances in ion exchange and advanced oxidation processes are greatly noteworthy. Recent progress in the non-membrane technologies, which are based on novel materials, are expected to enhance the removal efficiency of EfOM and even make it feasible to selectively remove undesirable fractions/compounds from bulk EfOM.