• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 1986년도 추계학술대회
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• pp.532.2-532
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• 1986

Alkaline protease which is an important enzyme used in detergents, leather tanning and food industry was produced by alkalophilic bacterium, Bacillus sp. KCTC 1723 isolated from soil. The maximum productivity of the enzyme in alkaline medium containing 1% sodium bicarbonate was obtained by incubating for 3 days at 37$^{\circ}C$. The optimum pH of the enzyme was 11.5 and calcium ion was effective on stabilization of the enzyme at high temperature. The enzyme was not inhibited by metal chelating agent such as El)TA but inhibited by diisopropyl fluorophosphate. Purification of the enzyme was carried out DEAE- and CM-cellulose column chromatographies and molecular weight of the purified enzyme was determined

• 한국결정성장학회지
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• 제8권2호
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• pp.350-355
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• 1998

Ethylene glycol을 polymeric carrier로 사용한 새로운 화학적 세라믹 분말 제조 공정에 의하여 $(Dy_2TiO_5)$ 분말을 제조하였다. Chelation 공정의 생략에도 불구하고, 고순도의 미세한 입자를 갖는 세라믹 분말 제조가 가능함을 확인하였다. 열분석, 미세구조분석, 회절분석 등으로 분말특성을 평가하였다.

• Bulletin of the Korean Chemical Society
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• 제29권1호
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• pp.43-46
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• 2008

The aim of present study was to examine the inhibitory effects of hydroxamic acid derivatives on the melanogenesis. We found that hydroxamic acid moiety was important for anti-melanogenic activity. Compounds 1a and 1b strongly inhibited melanin synthesis via deactivation of tyrosinase. Hydroxamic acid has metal ion chelating ability which is similar to that kojic acid, however, anti-tyrosinase mechanism of compounds 1a and 1b was different from that of kojic acid. They showed noncompetitive inhibition kinetics

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권5호
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• pp.379-382
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• 2004

Entomopathogenic nematodes are used for insect control. Herein, an extracellular protease was partially purified from a culture supernatant of Xenorhabdus nematophilus, a symbiotic bacterium of an entomopathogenic nematode, Steinernema glaseri: using precipitation with $80\%$ v/v isopropyl alcohol followed by gel permeation chromatography with a packed Sephacryl S-300 HR media. The partially purified protease exhibited maximal activity at pH 7 in the presence of 1 mM $CaCl_2$. The protease was identified as a metallo-protease based on the inhibition of its activity by the metal chelating agent, EDTA.

• Journal of Microbiology and Biotechnology
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• 제9권6호
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• pp.861-869
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• 1999

An extracellular protease was purified to homogeneity from the culture supernatant of psychrotrophic bacteria Bacillus sp. JH 108 using procedures including ammonium sulfate fractionation, anion exchange chromatography, gel filtration chromatography, and cation exchange chromatography. The enzyme exhibited a molecular weight of 36 kDa, an optimum pH of 8 to 9, and optimum temperature of $60^{\circ}C$. The enzyme preferentially hydrolyzed leucine at the N-terminus of peptides and thus can be classified as an aminopeptidase. It was strongly inhibited by metal chelating agents such as EDTA and l, l0-phenanthroline. The activity lost by EDTA was restored with $Zn^{2+}{\;}or{\;}Co^{2+}$. These divalent cations also stimulated the native enzyme. This suggests that the enzyme is a metalloprotease acting as a leucine aminopeptidase.

• Natural Product Sciences
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• 제12권4호
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• pp.226-231
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• 2006

Artemisia vulgaris, one of the most religious plants in Nepal, is used in the treatment of various ailments. In this study, antioxidative activity of essential oil from A. vulgaris was evaluated, using different in vitro methods and antimicrobial activity by disc diffusion method against skin disease microorganisms such as Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, Candida albicans and Propionibacterium acnes. The essential oil exhibited a concentration-dependent antioxidant activity. It showed strong metal chelating activity with low reducing and antioxidant power. However, gradual increase in radical scavenging activity was obtained with increasing concentration and reaction time. It also possessed a broad spectrum of antimicrobial activity and notable susceptibility was observed against S. pyogenes and P. acnes.

• 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 Microbiology and Biotechnology
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• 제9권4호
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• pp.381-385
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• 1999

Taq DNA polymerase from Thermus aquaticus has been shown to be very useful in a polymerase chain reaction. Taq DNA polymerase has a domain at the amino terminus (residues 1 to 290) that has 5'-3' exonuclease activity and a domain at the C-terminus that catalyzes the polymerase reaction. Taq DNA polymerase is classified into the Pol I family, which is represented by E. coli DNA polymerase I. The alignment of amino acid sequences for the 5'-3' exonuclease domains of the Pol I family DNA polymerases shows ten highly conserved carboxylic amino acids. Crystallographic studies suggested that six of the carboxylic amino acids are clustered within a 7 $\AA$ radius by chelating three metal ions in the active site. Those six carboxylic residues are mutagenized to alanines in order to better understand their function. All six carboxylic residues, Asp l8, Glu1l7, Asp1l9, Asp120, Asp142, and Aspl44, are crucial for catalysis of 5'-3' exonuclease.

• 한국환경과학회지
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• 제16권6호
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• pp.689-698
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• 2007

Mesoporous silicas for heavy metals adsorption were prepared by co-condensation of surfactant as a template and Ludox HS-40 as a silica precursor. Various mesoporous silicas with the introduction of chelating ligands (mercaptopropyl and aminopropyl groups) were synthesized to remove heavy metal ions from aqueous solutions. The surface modification was conducted with a co-condensation process using the sequential or simultaneous addition of mesoporous silica and high concentration of the organosilane(3-mercaptopropyltrimethoxysilane and 3-aminopropyltriethoxysilane). These materials have been characterized by elemental analysis, XRD, SEM and TEM analysis. Adsorbents synthesized with 3-mercaptopropyltrimethoxysilane and 3-aminopropyltriethoxysilane shows a high loading capacity for Hg(II), Pb(II), Cd(II) and anion Cr(VI). Especially the one synthesized with a mercaptopropyl function has the highest adsorption capacity for Hg(II) and Cd(II).

• Nutrition Research and Practice
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• 제2권4호
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• pp.247-251
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• 2008

This study investigated the antioxidant activity of methanol (MeOH) and water extracts from roots of Cirsium japonicum in vitro, MeOH extract showed a stronger tree radical scavenging activity than water extract. However, both of extracts showed a concentration dependent hydroxyl radical scavenging activity, reducing power and metal chelating ability, MeOH extract had greater phenolic and flavonoid contents than water extract. The antidiabetic activity of these two extracts was evaluated by the a-glucosidase inhibition assay, The water extract showed a considerable a-glucosidase inhibitory activity. To our knowledge, this may be the first time to report the antioxidant and antidiabetic activities in Cirsium japonicum roots.