• 제목/요약/키워드: Acidic

검색결과 3,299건 처리시간 0.025초

Aspergillus niger의 Acidic Nucleotidase의 특성 (Characterization of Acidic Nucleotidase from Aspergillus niger)

  • 김기남;박인식
    • 한국미생물·생명공학회지
    • /
    • 제20권1호
    • /
    • pp.40-45
    • /
    • 1992
  • Aspergillus niger로부터 acidic nucleotidase를 Sepharose CL-6B gel 여과와 DEAE-Sephacel 이온교환수지를 이용하여 부분정제하였다. 5'-AMP 와 3'-AMP를 기질로 사용했을 경우에 효소의 최적 pH는 4.5, 그리고 최적온도는 $55^{\circ}C$였다. 그러나, p-nitrophenyl phosphate를 기질로 사용했을 경우에는 최적 pH는 변화가 없었으나, 최적 온도는 $70^{\circ}C$였다. 효소의 활성화에너지는 3'-AMP, 5'-AMP 그리고 p-nitrophenyl phosphate를 기질로 사용했을 경우에 각각 4.76kcal/mole, 6.95kcal/mole 그리고 11.82kcal/mole 였다.

  • PDF

산으로 개질된 활성탄을 이용한 메틸 메르캅탄 악취물질 제거 (Removal of Odor- containing Sulfur Compound, Methyl Mercaptan using Modified Activated Carbon with Various Acidic Chemicals)

  • 김대중;서성규;김상채
    • 한국대기환경학회지
    • /
    • 제21권2호
    • /
    • pp.155-160
    • /
    • 2005
  • Removal of methyl mercaptan was investigated using adsorption on virgin activated carbon (VAC) and modified activated carbons with acidic chemicals in the present work. CAC, NAC, AAC and SAC were represented as activated carbons modified with HCI, HNO$_{3}$, CH$_{3}$COOH and H$_{2}$S0$_{4}$ ,respectively The pore structures were evaluated using nitrogen isotherm. The surface properties of virgin activated carbon and modified activated carbons were characterized by EA, pH of carbon surface and acid value from Boehm titration. The modification of activated carbon with acidic chemicals resulted in a decrease in BET surface area, micropore volume and surface pH, but an increase in acid value. The order of the adsorption capacity of activated carbons was NAC>AAC>SAC>CAC>VAC, and in agreement with that of acid value of activated carbons, whereas in disagreement with that of micropore volume of activated carbons. It appeared that chemical adsorption played an important role in methyl mercaptan on modified activated carbons with acidic chemicals compared to virgin activated carbon. Modifying activated carbon with acidic chemicals enabled to significantly enhance removal of methyl mercaptan.

콩 발효식품으로부터 분리한 페놀물질획분의 성분분석과 항산화 작용 특성 (Composition and Antioxidative Characteristics of Phenolic Fraction Isolated from Soybean Fermented Food)

  • 이정수;최홍식
    • 한국식품영양과학회지
    • /
    • 제26권3호
    • /
    • pp.383-389
    • /
    • 1997
  • Doenjang(fermented soybean paste) was prepared by the series of processes including soaking, cooking, first fermentation(3 days at 30$\pm$2$^{\circ}C$) for the preparation of meju(soybean koji) after inoclulation of Aspergillus oryzae, and further fermentation (60 days at 30$\pm$2$^{\circ}C$) for the ripening after addition of salt 13% to meju. the crude phenolics extracted from defatted soybean and doenjang were fractionated onto the neutral phenolics(isofavonoids) and acidic phenolics(phenolic acids), respectively. Composition and antioxidative characteristics of phenolic fractions were determined. The neutral phenolic fractions contained genistin, genistein and daidzein; on the other hand, acidic phenolic fractions had syringic acid and seven other components. The content of genistin in doenjang dramatically decreased at the early stage of fermentation, whereas the content of genistein rather increased. In addition, the content of syringic acid of acidic phenolic fractions were increased during fermentation. These changes in individual phenolic components affected the antioxidative activity of neutral phenolics or acidic phenolics. antioxidative activity of phenolic compounds were evaluated during soybean fermentation. The antioxidative and free radical scavenging activity of neutral phenolic fractions and acidic phenolic fractions on linoleic acid autoxidation were also investigated.

  • PDF

산수용액에서 처리된 흑연 구조와 열적 특성 (Structural and Thermal Characteristics of Graphites Treated in Acidic Solutions)

  • 송승원;민의홍;이동원;김정수;오원태
    • 한국재료학회지
    • /
    • 제27권2호
    • /
    • pp.113-118
    • /
    • 2017
  • Natural and expandable graphites were chemically treated in acidic aqueous solutions such as acetic acid or mixtures of acetic acid and nitric acid. Structures and thermal conductivities of the as-treated graphites were characterized in detail. Both graphites were significantly oxidized in the mixed acidic solution of $H_2SO_4$ and $HNO_3$, which condition was generally used for the oxidation of carbon nanotubes. This considerable oxidation of graphites caused a depression of their thermal conductivity. The structural characteristics, obtained by XRD and XPS, show that the graphites treated in the relatively weak acidic conditions (acetic acid or mixture of acetic acid and nitric acid) were quite similar to the untreated graphites. However, the thermal conductivities of both acidic-treated graphites were remarkably increased.

Study on Atitumor and Immunomodulating Acivities of Polysaccharide Fractions from Panax ginseng : Comparison of effects of neutral and acidic polysaccharide fraction

  • Kim, Young-Sook;Kang, Kyu-Sang;Kim, Shin-Il
    • Archives of Pharmacal Research
    • /
    • 제13권4호
    • /
    • pp.330-337
    • /
    • 1990
  • The crude polysaccharide from Panax ginseng prepared by hot water extration and precipiation with ethanol was further fractionated into neutral and acidic fractions by DEAE- cellulose ion exchange chromatography. The chemical compositions were 85.0% carbohydrorate and 15.0% protein for the neutral fraction, and 28.4% carbohydrate, 10.0% protein and 29.0% uronic acid for the acidic fraction. The acidic fraction was more effective in increasing of the ratio of spleen to body weight, the number of antibody secreting cells to SRBC and phagocytic activity of reticuloendothelial system, as well as antitumor activity against the solid form of sarcoma 180 in ICR mice than the neutral fraction. All polysaccharide fractions were mitogenic to cultured spleen cells of C57BL/6 mice. However, FA was different from FN in the co-mitogenicities with lectin mitogens. Both crude and acidic fractions potentiated remarkably the mitogenic activity of PHA-P or LPS in dose-dependent manner but neutral fraction enhanced only that of LPS. Three polysaccharide fractions had no effect on that of Con A. These results suggest that the acidic fraction may stimulate B and Td cells as well as macrophages while the neutral fraction may simulate only B cells and macropages.

  • PDF

백삼 알코올 추출박을 이용한 산성다당체 다량 함유 백삼 농축액 제조 (Preparation of Ginseng Concentrate with High Content of Acidic Polysaccharide from White Tail Ginseng Marc)

  • 강태화;박경준;강성태
    • 한국식품영양과학회지
    • /
    • 제33권4호
    • /
    • pp.736-740
    • /
    • 2004
  • 50% 에탄올 추출박으로부터 기존의 백삼농축액보다 산성다당체가 다량 함유된 백삼 농축액 제조 방법에 대해서 연구하였다. 50% 에탄올을 사용하여 제조한 백삼농축액의 추출 수율과 산성다당체 함량은 에탄올의 농도가 증가할수록 감소하였다. 반면에 백삼을 0∼90% 에탄올로 추출하고 남은 백삼박 내의 산성다당체 함량은 에탄올 농도가 증가할수록 증가하였다. 백삼박으로부터 산성다당체를 얻을 수 있는 최적의 조건은 $\alpha$-amylase를 390∼650 unit/g residue/15 mL 증류수의 농도로 4$0^{\circ}C$에서 5분 동안 처리하는 것으로 확인되었다. 50% 에탄을 추출 후 남은 백삼박에 $\alpha$-amylase를 처리함으로써 백삼박의 물추출액 중의 산성다당체 함량은 무처리구의 8.3%에서 10.5%로 증가하였다. 기존의 50% 에탄올 백삼추출농축액과 본 실험을 통하여 얻어진 백삼박 추출액을 8:2(w/w)로 혼합한 새로운 흔합백삼농축액을 제조한 결과 기존의 인삼농축액에 비해 조사포닌 함량은 비슷하며 약2배 정도의 산성다당체를 함유하고 색도가 짙은 농축액을 제조할 수 있었다.

Effects of acidic pH on voltage-gated ion channels in rat trigeminal mesencephalic nucleus neurons

  • Han, Jin-Eon;Cho, Jin-Hwa;Choi, In-Sun;Kim, Do-Yeon;Jang, Il-Sung
    • The Korean Journal of Physiology and Pharmacology
    • /
    • 제21권2호
    • /
    • pp.215-223
    • /
    • 2017
  • The effects of acidic pH on several voltage-dependent ion channels, such as voltage-dependent $K^+$ and $Ca^{2+}$ channels, and hyperpolarization-gated and cyclic nucleotide-activated cation (HCN) channels, were examined using a whole-cell patch clamp technique on mechanically isolated rat mesencephalic trigeminal nucleus neurons. The application of a pH 6.5 solution had no effect on the peak amplitude of voltage-dependent $K^+$currents. A pH 6.0 solution slightly, but significantly inhibited the peak amplitude of voltage-dependent $K^+$ currents. The pH 6.0 also shifted both the current-voltage and conductance-voltage relationships to the depolarization range. The application of a pH 6.5 solution scarcely affected the peak amplitude of membrane currents mediated by HCN channels, which were profoundly inhibited by the general HCN channel blocker $Cs^+$ (1 mM). However, the pH 6.0 solution slightly, but significantly inhibited the peak amplitude of HCN-mediated currents. Although the pH 6.0 solution showed complex modulation of the current-voltage and conductance-voltage relationships, the midpoint voltages for the activation of HCN channels were not changed by acidic pH. On the other hand, voltage-dependent $Ca^{2+}$ channels were significantly inhibited by an acidic pH. The application of an acidic pH solution significantly shifted the current-voltage and conductance-voltage relationships to the depolarization range. The modulation of several voltage-dependent ion channels by an acidic pH might affect the excitability of mesencephalic trigeminal nucleus neurons, and thus physiological functions mediated by the mesencephalic trigeminal nucleus could be affected in acidic pH conditions.

무화과 잎의 용매분획 및 항미생물 활성 (Solvent Fractionation of Fig Leaves and its Antimicrobial Activity)

  • 강성국;정희종
    • Applied Biological Chemistry
    • /
    • 제38권4호
    • /
    • pp.289-292
    • /
    • 1995
  • 무화과잎으로부터 천연 항미생물 물질의 개발을 검토할 목적으로 무화과잎을 메탄올로 추출하고 ethyl acetate와 buffer용액을 이용하여 용매분획하였고 각 분획에 대한 항미생물 활성을 측정하였으며 활성이 강한 분획에 대한 최소저해농도(MIC)와 최소치사농도(MLC)를 측정하였다. 무화과 잎중의 항미생물 활성은 산성 분획과 페놀성 분획에서 강하게 나타났으며 미생물의 종류에 관계없이 활성범위가 넓었다. 페놀성 분획이 산성 분획에 비하여 MIC와 MLC값이 상대적으로 낮았고 MIC값의 경우 두 분획이 공통적으로 세균보다는 진균류에 대하여 낮았으며 특히 저온세균인 Pseudomonas aeruginosa에 대한 MIC와 MLC값이 대단히 낮음을 알 수 있었다.

  • PDF

Production of an Acidic Polygalacturonase from Aspergillus kawachii by Solid State Fermentation and Their Application for Pectin Extraction

  • Martinez-Avila, Guillermo Cristian Guadalupe;Wicker, Louise;Aguilar, Cristobal Noe;Rodriguez-Herrera, Raul;Contreras-Esquivel, Juan Carlos
    • Food Science and Biotechnology
    • /
    • 제18권3호
    • /
    • pp.732-738
    • /
    • 2009
  • An acidic polygalacturonase (PG) from Aspergillus kawachii was produced by solid state fermentation employing a polyurethane foam support. The conditions used for the production of acidic PG were particle size of support (0.6 or 500 $mm^3$) and fermentation time. From the factors studied, the particle size had important influence on enzyme production. The best conditions for acidic PG production were $0.6\;mm^3$ particle size, 18 hr at $30^{\circ}C$ and initial pH of 5.0. In addition, pectin was extracted from citrus pomaces (grapefruit, lime, and tangerine) by acidic PG at $50^{\circ}C$ for 24 hr with citric acid solution. Infrared spectroscopy showed that lime pomace had more high-methoxylated (65%) endogenous pectin than was obtained than from grapefruit or tangerine pomaces. The enzymatically extracted pectin yield in dry basis (d.b.) for grapefruit and lime pectins were 6.95 and 4.25%, respectively. The citric acid solution alone also contributed to pectin extraction from citrus pomaces (7-9%, d.b.). Limited pectin extraction by acidic PG from tangerine pomace was most likely due to the presence of low-methoxylated endogenous pectin. The enzymatic method for pectin extraction using acidic PG from A. kawachii is a promising technique for releasing highly polymerized pectic substances from high-methoxylated lime or grapefruit pomaces.

화학사고 빈도가 높은 산 계열 물질의 취급 특성 연구 (A Study on the Characteristics of Production and Using for Acidic Chemicals with High Accident Frequency)

  • 김기준;이진선;윤영삼;정미숙;윤준헌;석광설
    • 한국위험물학회지
    • /
    • 제2권1호
    • /
    • pp.1-5
    • /
    • 2014
  • Acidic chemicals like sulfuric acid, nitric acid and hydrogen chloride take up 37% of the total chemical accidents which took place for the past 10 years. When an acidic chemical leak happens, fume is generated, diffusing into the air, which might cause serious damage to health of local residents and the environment. However, we have only little reference data for production and using of acidic chemicals. In this study, we investigated characteristics of production and using for acidic chemicals with high accident frequency. As a results, domestic chemical accidents were categorized according to chemical types and production, using, and handling characteristics of acidic chemicals were identified. Sulfuric acid was handled in the largest amount, followed in the order of hydrogen chloride, nitric acid, acrylic acid, and hydrogen fluoride. Sulfuric acid is used in the industry of manufacturing composite fertilizer and mainly used for manufacturing fertilizer. Hydrogen chloride is used in the industry of manufacturing basic chemicals for petrochemical family and mainly used for pH regulator. It is expected that this results could be used as preliminary data for making decisions on facilities required intensive management in order to prevent chemical accidents and prepare countermeasures against such accidents.