• Title, Summary, Keyword: enzyme activity

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Thermostability of Superoxide Dismutase from Cucumber(Cucumis sativa) (오이 추출물에 존재하는 Superoxide Dismutase의 열안정성)

  • 박인식;김은애;김기남;길지은;이민경;김석환;서정식
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.27 no.6
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    • pp.1105-1109
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    • 1998
  • The superoxide dismutase(SOD) in peeled pericarp of cucumber was most stable at pH 8.0 and relatively stabe between pH 5.0 and 9.0. The enzyme was stable up to 6$0^{\circ}C$ and retained 12% by heat treatment at 10$0^{\circ}C$ for 5 min. At pH 2.0, the peeled pericarp enzyme activity was decreased to 10% by incubation for 3 hrs. However, the enzyme activity was increased above 25% after incubating the enzyme at pH 7.0 for 6 hrs. Retention of SOD activity in cucumber by various heating methods was also measured. The residual SOD activities of peeled pericarp and whole cucumber was estimated to be 25% and 27% after blanching(2 min), respectively. The skin enzyme retained 53% of its activity after steaming (3 min). When the peeled pericarp enzyme was incubated at 4$^{\circ}C$ for 20 days, the enzyme activity remained about 81%. However, when the enzyme incubated at 3$0^{\circ}C$ for 20 days, the peeled pericarp enzyme activity decreased to 17% of its original activity. The enzyme activity of peeled pericarp cucumber was not changed after exhaustive dialysis for 3 days, which indicated that the SOD activity in cucumber seems to have molecular weight above 12,000.

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The Effects of Amino Acids and Metaolites on the Biosynthesis of Biodegradative Theronine Dehydratase in Serratia matcescens ATCC25419 (아미노산과 대사산물들이 Serratia marcescens Biodegradative Threonine Dehydratase의 생합성에 미치는 영향)

  • 최병범;김승수
    • Microbiology and Biotechnology Letters
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    • v.23 no.1
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    • pp.24-30
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    • 1995
  • The effects of amino acids in growth media on the biosynthesis of Serratia marcescens biodegradative threonine dehydratase activity were examined. The enzyme activity was decreased by 44 and 34% by 10 mM isoleucine and valine, respectively, whereas it was increased approximately by 20% by 10 mM threonine. Among several metabolites tested, pyruvate increased the enzyme activity by 60% at 5 mM, but decreased the enzyme activity approximately by 20 to 70% above 20 mM. The enzyme activity was increased by 64% by 5 mM glyoxylate, whereas it decreased the enzyme activity approximately by 40 to 70% above 20 mM glyoxylate. The thiamine, monopyrrole derivative, also increased the enzyme activity by 84% at 50 $\mu $g/ml, but did not affected the enzyme activity above 300 $\mu $g/ml. cAMP increased the enzyme activity by 58% at 0.5 mM, but decreased the enzyme activity by 15% at 2 mM. These data suggested that the biosynthesis of Serratia marcescens biodegradative threonine dehydratase is regulated by concentrations of pyruvate, glyoxylate and cAMP.

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Enzyme Activity and Beating Properties for Preparation of MicroFibrillated Cellulose(MFC) (MicroFibrillated Cellulose(MFC) 제조를 위한 전처리 효소의 활성 및 고해 특성)

  • Kim, Kang-Jae;Jung, Jin-Dong;Jung, Soo-Eune;Ahn, Eun-Byeoul;Eom, Tae-Jin
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.47 no.1
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    • pp.59-65
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    • 2015
  • In this study, we evaluated optimum condition of enzyme with pH and temperature for preparation of microfibillated cellulose(MFC). Well-known endo-glucanase, three enzymes were used and CMC was used for substrate. Enzyme activity was evaluated using DNS method and absorbance with UV/VIS spectrophotometer. The enzyme shown the greatest activity was reacted with pulps at optimum condition for 1 hour and treated pulps beated until 100 mL CSF. Enzyme B and Enzyme L was the higher enzyme activity below 0.1% concentration and Enzyme N was the lowest enzyme activity. At various pH and temperature conditions, enzyme activity of Enzyme B was higher than the others at the same concentration. Especially enzyme activity at $50^{\circ}C$ of Enzyme B was almost not changed over pH 6.0. Optimum condition of three enzyme was pH 6 or pH 7 and $50^{\circ}C$ or $60^{\circ}C$. Also beating efficiency of enzyme treated pulps with Enzyme B is 55.6%.

Purification and Biochemical Analysis of Rice Bran Lipase Enzyme

  • Kim, Young Hee
    • Journal of Plant Biotechnology
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    • v.6 no.1
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    • pp.63-67
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    • 2004
  • A simple procedure for the extraction of the lipolytic enzyme from rice bran has been developed. High activity of lipolytic enzyme was obtained by first defatting the rice bran to remove lipid components with various extraction conditions. Then, after rove cycles of aqueous extraction, rice bran lipolytic enzyme was purified using micro- and ultrafiltration apparatus. Lipolytic enzyme activity was estimated by its hydrolytic action of tributyrin. The result indicated that the standard activity curve of butyric acid showed that the potential rice bran enzyme is a hydrolytic lipase enzyme. In addition, it showed higher lipolytic activity and specific enzyme activity with further purification by micro- and ultrafiltration. The size of rice bran lipase enzyme was identified through 15 % SDS-PAGE. The molecular weight of the rice bran lipase enzyme was 41 kDa.

Chemical Modification of Extracellular Cytosine Deaminase from Chromobacterium violaceum YK 391

  • Kim, Tae-Hyun;Yu, Tae-Shick
    • Journal of Microbiology and Biotechnology
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    • v.8 no.6
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    • pp.581-587
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    • 1998
  • Essential amino acids involved in the catalytic role of the extracellular cytosine deaminase from Chromobacterium violaceum YK 391 were determined by chemical modification studies. The enzyme activity required the reduced form of Fe (II) ion, since the enzyme was inhibited by ο-phenanthroline. The enzyme activity was completely inhibited by the chemical modifiers, such as p-chloromercuribenzoate (p-CMB), p-hydroxymercuribenzoate, and chloramine-T at 1 mM each. The enzyme activity was also markedly inhibited by pyridoxal-5'-phosphate, diethyl pyrocarbonate, and phenylmethylsulfonyl fluroride at 1 mM each. The inactivation of the enzyme activity with p-CMB was reversed by a high concentration of cytosine. Furthermore, the inactivation of the enzyme activity with p-CMB was also reactivated by 1 mM dithiothreitol, 1 mM 2-mercaptoethanol, 1 mM cysteine-HCI, 10% ethyl alcohol, and 10% methyl alcohol. These results suggested that cysteine and methionine residues might be located in or near the active site of the enzyme, while lysine, histidine, and serine residues might be indirectly involved in the enzyme activity.

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A Study on the Remaining Concentration of Pesticides in Tap Water of Taejon City by Ellman′s Enzyme Method and the Countermeasure (Ellman 효소법에 의한 대전시 상수도내 살충제의 잔류농도 결정 및 그 대책에 관한 연구)

  • 이봉호;이영순;전종한
    • Journal of Environmental Science International
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    • v.8 no.1
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    • pp.19-26
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    • 1999
  • The degree of pesticides accumulation in tap water in Taejon from June 1995 to Apr 1996 was measured by Ellman's coupled enzyme assay. Since organic phosphate and carbamate pesticides specifically inhibit the neurotransmitter modulating enzyme acetylcholinesterase(AChE), the enzyme activity can be used as a diagnosis for the pesticides accumulation in water and various samples. During the period of this study, the enzyme activity was changed almost every week. The lowest enzyme activity was 64 % of that of the control reaction and there are several days showing about 100 % enzyme activity. In general, the enzyme activity is higher in summer than other seasons especially early spring times. The pH value of tap water was very close to neutral(pH 7.0) and it seems that the enzyme activity was not affected by the small pH changes. Either boiling of tap water or addition of NaOH solution decomposed the pesticide components. These results show that AChE assay is a convenient, sensitive, and reliable method for detection of pesticides in water samples.

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Studies on Higher Fungi in Korea (I) -Activity of Proteolytic Enzyme from Sarcodon aspratus (Berk) S. Ito- (한국산 고등균류에 관한 연구(제 1보) -능이버섯의 단백분해효소 활성-)

  • Eun, Jae-Soon;Yang, Jae-Heon;Cho, Duck-Yee;Lee, Tae-Kyu
    • Journal of Pharmaceutical Investigation
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    • v.18 no.3
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    • pp.125-131
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    • 1988
  • This study was undertaken to investigate the proteolytic enzyme from Neungee mushroom [Sarcodon aspratus (Berk) S. Ito]. The proteolytic activity of Neungee was higher than other several edible mushrooms under various pHs. The potency of proteolytic enzyme of Neungee was same as the digestive drugs containing protease. So the proteolytic activity of the enzyme was increased in neutral or weak alkaline pH, whose characteristics would be alkaline protease. The specific activity of the purified enzyme obtained by using Tris acryl CM-cellulose ion exchange increased 20 times as compared with that of the crude extract. The proteolytic enzyme was stable at room temperature, but decomposition was fast when incubated at higher temperature more than $40^{\circ}C$. The half life of the enzyme was longest in neutral pH and rate constant was increased in acidic or alkaline solution.

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Recycling of Wastepaper(Ⅶ)-The Effect of Stock Composition on Enzyme Activity- (고지재생연구(제 7보)-지료조성이 효소활성에 미치는 영향-)

  • 여성국;류정용;신종호;송봉근;오세균
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.31 no.3
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    • pp.1-9
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    • 1999
  • Effect of furnish on enzyme activity was investigated by using the three components (cellulose, enzyme, and cationic polyelectrolyte) model papermaking system. Avicel was used as a cellulose model compound to observe the effect of adsorption and desorption of enzyme with other component and the resultant change of particle size. As an experimental result, the enzyme loses considerably its apparent activity due to the adsorption onto cellulose and cationic polyelectrolyte. Activities of enzyme applied to the actual papermaking stocks having controlled fiber length showed different behavior in terms of pulp species UKP and KOCC stocks. That is, the enzyme activity in UKP was increased as fines content increased, however, vice versa in KOCC stock . This result can be considered to be the existence of various contaminants included in the fines of KOCC . The effect of possible contaminants such as inorganic materials, calcium ion, surfactant, and conductivity on enzyme activity were also investigated.

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Purification and Biochemical Analysis of Rice Bran Lipase Enzyme (쌀겨로부터 lipase 효소의 정제 및 생화학적인 분석)

  • Kim Younghee
    • Proceedings of the KAIS Fall Conference
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    • pp.299-301
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    • 2004
  • A simple procedure for the extraction of the lipolytic enzyme from rice bran has been developed. High activity of lipolytic enzyme was obtained by first defatting the rice bran to remove lipid components with various extraction conditions. Then, after five cycles of aqueous extraction, rice bran lipolytic enzyme was purified using micro- and ultrafiltration apparatus. Lipolytic enzyme activity was estimated by its hydrolytic action of tributyrin. The result indicated that the standard activity curve of butyric acid showed that the potential rice bran enzyme is a hydrolytic lipase enzyme. In addition, it showed higher lipolytic activity and specific enzyme activity with further purification by micro- and ultrafiltration.

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Purification and Enzymatic Characteristics of Myrosinase from Korea Cabbage (배추 Myrosinase의 정제 및 효소학적 특성)

  • 심기환;강갑석;서권일
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.24 no.4
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    • pp.563-569
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    • 1995
  • Myrosinase from Korean cabbage(Bogdoli) was purified and its enzymatic properties were investigated. Myrosinase from the Korean cabbage was purified by DEAE Bio-Gel Sepharose, Concanavalin-A, and Mono-Q column chromatography and exhibited a 55KD molecular weight with a single band on the gel of SDS-PAGE. The enzyme was purified about 21-fold compared to its crude enzyme and a specific activity of purified enzyme was 15, 120units/mg. Optimum pH of the myrosinase was 7.0 in both phosphate and Tris-HCl buffer solutions, the enzyme was stable at pH 6.5~7.0. Optimum temperature of enzyme was 37~38$^{\circ}C$. The enzyme activity was significantly inhibited by Cu2+ and Hg2+, but enhanced by ascorbic acid, resulting in a maximum activity at 1mM ascorbic acid. Among the ascorbic acid analogues, dehydro-ascorbic acid did not affect, whereas others showed a little effect on the enzyme activity, but less than ascorbic acid itself. Reducing agents such as 2-mercaptoethanol and dithiothreitol had no effect on the enzyme activity, but the enzyme activity was enhanced when 2-mercaptoethanol was mixed with ascorbic acid.

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