• 미생물학회지
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• 제29권3호
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• pp.167-171
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• 1991

An intracellular protease from cells of Pseudomonas carboxydohydrogena grown on nutrient broth was purified to better than 95% homogeneity in five steps using azocaseine as a substrate. The molecular weight of the native enzyme was determined to be 125, 000. Sodium dodecyl sulfate-gel electrophoresis revealedat least two non-identical subunits of molecular weight 70, 000 and 56, 000. The enzyme activity was completely ingibited by phenylmethylsulfonyl fluoride and diisopropyl fluorophosphate. The enzyme was also inhibited by $Mg^{2+}$ , $Zn^{2+}$ , $Cd^{2+}$, $Cu^{2+}$ , and $Fe^{2+}$ , but was stimulated by iodoacetamide. Maximal reaction rate of the enzyme was observed at pH8.0 and 30.deg.C. The isoelectric point of the enzyme was found to be 7.5. The enzyme was unable to hydrolyze carbon monoxide dehydrogenase.

• Journal of Life Science
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• 제9권1호
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• pp.64-68
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• 1999

The properties of purified intracellular adenosine deaminase (adenosine aminohydrolase, EC 3.5.4.4) of Nocardioides sp. J-326TK isolated from soil have been studied. The enzyme deaminated adenosine and 2`-deoxyadenosine and the respective {TEX}$K_{M}${/TEX} values were 4.0×{TEX}$10^{-4}${/TEX} M and 5.0× {TEX}$10^{-4}${/TEX} M, but the enzyme was not active on 8-bromoadenosine, 6-methylaminopurine riboside, ATP, ADP, 2`-AMP, 3`-AMP, 5`-AMP, dAMP, cAMP, NAD, FAD, NADP and adenine. The enzyme activity was strongly inhibited by the addition of {TEX}$Hg^{2+}${/TEX} and {TEX}$Ag^{+}${/TEX}, {TEX}$Cu^{2+}${/TEX}, {TEX}$Co^{2+}${/TEX} and {TEX}$Mn^{2+}${/TEX} also inhibited the activity but much less extent. The effect of alkyl reagents, metal chelating reagents and certain other compounds on the enzyme activity were also examined. No reagent activated the enzyme. On the contrary, the enzyme reaction was slightly inhibited by o-phenanthroline and 6-benzyladenosine.

• Journal of Ginseng Research
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• 제7권1호
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• pp.80-87
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• 1983

In an endeavour to elucidate effects of ginseng on some characteristics of enzymes, malate dehydrogenase (EC 1.1.1.37) was chosen as a model enzyme and effects of ginseng saponin on the enzyme such as optimum pH, product inhibition, optimum temperature and the activity was investigated. The product inhibition by NADH-a reaction product of the enzyme-was increased 33% by 0.3% ginseng saponin. And the optimum pH of the enzyme was 8.3 but in the presence of 0.3% ginseng saponin it increased to 8.5. The enzyme activity and the optimum temperature was not affected by ginseng saponin in the concentration of 1.0% and 0.3%, respectively. In this work, the possibility of contribution of ginseng saponin to the adaptogen activity is suggested; Potentiation of the regulatory activity of an enzyme may contribute to the normalization of the physiological state and consequently may increase the nonspecific resistance of an organism.

• 한국식품영양학회지
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• 제7권2호
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• pp.87-94
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• 1994

A protease, actinidin, was isolated from Cheju kiwi fruit Actinidia chinesis. The enzyme was purified about 8.5 fold with the yield of 25% by column chromatographies of DEAE-Toyopearl and Sphadex. G-100. Purified enzyme gave a single protein band on polyacrylamide gel electrophoresis and its molecular weight estimated by SDS-PAGE was about 27, 000. The optimum pH and temperature were 7.0 and 4$0^{\circ}C$, respectively. This enzyme was stable at the ranges of pH 5.0~9.0 and below 5$0^{\circ}C$. It was also found that Fe+2, Fe+3, and Na+ ions increased enzyme activity, whereas Hg+2 and Co+2 ions decreased. The enzyme was inhibited by phenylmercuric acetate and leupeptin, which indicated that active center of the emzyme had thiol-group. The enzyme reaction followed the Michaelis-Men-ten dkinetics with the Km value of 0.32 mM for casein.

• 한국환경과학회지
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• 제8권1호
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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.

• Parasites, Hosts and Diseases
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• 제37권2호
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• pp.109-115
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• 1999

The present study observed the variation of antigenicity of Pneumocystis carinii and serum IgG antibody reastion to the antigens from different localtities in Korea. Antigens of rat P,carinii and sera of inhabitants were collected at Chunchon, Chungju, Kwangju and Seoul during 1995-1996. Enzyme-Linked Immunosorbent Assay and immunoblot were used for immune reaction. Absorbance of 1,294 human sera ranged between 0.01and 0.93. Sera from Chunchon showed higher absorbances than those from other areas. Immunoblotting revealed IgG antibody reactions to 116,100, and 45-55 kDa antigenic bands of rat P.carinii, but the frequencies of positive reaction to individual bands were variable by localities. Total 62.6% reacted to 100kDa band and 32.0% to 45-55 kDa bands. For the reaction to 116kda, the reaction rate was 60.0% of the sera showed the reaction to 116kda band while 37.7% reacted to 100kda, the reaction rate was 60.0% to 82.6% by localities. It is found that the reaction rates of the human sera to rat P.carinii antigen are variable according to the localities. Also, the high molecular antigen of 116kDa of rat P.carinii is the most frequent antigenic band reaction to human sera.

• 대한세포병리학회지
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• 제12권1호
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• pp.25-30
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• 2001

Tuberculous lymphadenitis is not uncommon in Korea. Therefore, an inexpensive, safe and rapid method is needed to diagnose the tuberculous lymphadenitis. Flne needle aspiration cytology Is a good method for this purpose, but has several limitations in the diagnosis of tuberculous lymphadenitis, especially when the presence of acid-fast bacilli is not proved. To evaluation the usefulness of the polymerase chain reaction with enzyme immunoassay technique in the detection of Mycobacterium tuberculosis (M. tuberculosis) In the cervical Iymph node asplrates, the authors performed fine needle aspiration cytology and M. tuberculosis PCR with enzyme immunoassay for mycobacterial DNA sequences from 15 cases of the fine needle aspirates. Cytomorphologically, the cases were categorized into three types: predominantly necrotic materials; typical epithelioid cell granulomas with or without slant cells and caseous necrosis; and non-tuberculous lesions, such as reactive lymphadenitis, abscess, metastatic carcinoma and malignant lymphoma. M. tuberculosis DNA was found in 8 of 15 cases by PCR with enzyme immunoassay. Negative findings on PCR were achieved in 7 cases, which revealed non-tuberculous tymphadenopathy. In conclusion, we suggest that M. tuberculosis PCR with enzyme immunoassay using the fine needle aspirates is a very useful tool for the diagnosis of tuberculous lymphadenitis.

• 한국식품과학회지
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• 제10권4호
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• pp.380-386
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• 1978

Streptomyces spp. K-14에서 생성되는 포도당 이성화효소의 특성에 대해서 연구하였다. 효소 반응의 최적 pH와 온도는 5 mM $MgSO_4{\cdot}7H_2O$와 2 mM $CoCl_2{\cdot}6H_2O$의 존재 아래에 각각 $7.5{\sim}8.0$ 그리고 $70^{\circ}{\sim}75^{\circ}C$로 나타났다. 이러한 이성화 효소는 $Mg^{++}$과 $Co^{++}$두 양이온에 의하여 활성화 되었는데 $Mg^{++}$는 이성화 반응의 초기 활성화에 소요 되었으며 $Co^{++}$는 효소 단백질을 안정화 하는데 소요 되었다. 포도당 농도 60%까지는 효소 반응속도나 효소의 이성화율에 영향을 끼치지 않았다.

• Applied Biological Chemistry
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• 제28권1호
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• pp.1-7
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• 1985

Pseudomonas stutzeri IAM 12097이 생산(生産)하는 Exo-maltotetraohydrolase는 soluble starch, amylose, amylopectin, oyster glycogen, corn, potato, glutinous rice, green banana, arrow root 의 호화전분(糊化澱粉), maltopentaose, maltohexaose, maltoheptaose, maltooctaose를 가수분해(加水分解)하였으나, ${\alpha},{\beta},{\gamma}-cyclodextin$, sucrose, raffinose, pullulan, maltose, maltotriose, maltotetraose는 분해(分解)하지 못하였다. 소당류중(少糖類中) maltohexaose를 가장 잘 분해(分解)하였으며, 각종기질(各種基質)의 주분해산물(主分解産物)은 maltotetraose였다. pullulanase의 혼용(混用)으로 호화전분(糊化澱粉)의 분해율(分解率)은 증가(增加)되었으나 생전분(生澱粉)에 대(對)하여는 혼용효과(混用效果)를 인정(認定)할 수 없었고 생전분중(生澱粉中)에서 corn starch가 가장 잘 분해(分解)되며 raw potato starch, raw arrow root starch, raw high amylose corn starch의 분해(分解)는 미약(微弱)하였다.

• Journal of Microbiology and Biotechnology
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• 제31권3호
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• pp.419-428
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• 2021

To efficiently recycle GH78 thermostable rhamnosidase (TpeRha) and easily separate it from the reaction mixture and furtherly improve the enzyme properties, the magnetic particle Fe3O4-SiO2-NH2-Cellu-ZIF8 (FSNcZ8) was prepared by modifying Fe3O4-NH2 with tetraethyl silicate (TEOS), microcrystalline cellulose and zinc nitrate hexahydrate. FSNcZ8 displayed better magnetic stability and higher-temperature stability than unmodified Fe3O4-NH2 (FN), and it was used to adsorb and immobilize TpeRha from Thermotoga petrophilea 13995. As for properties, FSNcZ8-TpeRha showed optimal reaction temperature and pH of 90℃ and 5.0, while its highest activity approached 714 U/g. In addition, FSNcZ8-TpeRha had better higher-temperature stability than FN. After incubation at 80℃ for 3 h, the residual enzyme activities of FSNcZ8-TpeRha, FN-TpeRha and free enzyme were 93.5%, 63.32%, and 62.77%, respectively. The organic solvent tolerance and the monosaccharides tolerance of FSNcZ8-TpeRha, compared with free TpeRha, were greatly improved. Using naringin (1 mmol/l) as the substrate, the optimal conversion conditions were as follows: FSNcZ8-TpeRha concentration was 6 U/ml; induction temperature was 80℃; the pH was 5.5; induction time was 30 min, and the yield of products was the same as free enzyme. After repeating the reaction 10 times, the conversion of naringin remained above 80%, showing great improvement of the catalytic efficiency and repeated utilization of the immobilized α-L-rhamnosidase.