• 한국자기공명학회논문지
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• 제19권2호
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• pp.67-73
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• 2015

The microcystin is a cyclic heptapeptide from metabolites of cyanobacteria in the genera mycrocystis, anabaeba as a result of eutrophication. It has been known that microcystin-LR is a potent inhibitor of the catalytic subunits of protein phosphatase-1 (PP-1) as well as powerful tumor promoter. The active site of microcystin actually has two metal ions $Fe^{2+}/Zn^{2+}$ close to the nucleophilic portion of PP-1-microcystin complex. We report the isolation and purification of this microcystin-LR from cyanobacteria (blue-green algae) obtained from Daechung Dam in Chung-cheong Do, Korea. Microcystin-LR was extracted from solid-phase extraction (SPE) sample preparation using a CN cartridge. The cyanobacteria extract was purified to obtain microcystin-LR by HPLC method and identified by LC/MS. The detail structural studies that can elucidate the possible role of monovalent and divalent metal ions in PP-1-microcystin complexation were carried out by utilizing molecular dynamics. Conformational changes in metal binding for ligands were monitored by molecular dynamic computation and potential of mean force (PMF) using the method of the free energy perturbation. The microcystin-metal binding PMF simulation results exhibit that microcystin can have very stable binding free energy of -10.95 kcal/mol by adopting the $Mg^{2+}$ ion at broad geometrical distribution of $0.5{\sim}4.5{\AA}$, and show that the $K^+$ ion can form a stable metal complex rather than other monovalent alkali metal ions.

• KSBB Journal
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• 제32권2호
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• pp.160-167
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• 2017

Coating of individual cells with organic or inorganic materials has drawn a great deal of attention, because it provides the cells with physicochemical durability, which would contribute to the development of bioreactors, biosensor, and lab-on-a-chip, as well as to the fundamental studies in single cell-based biology. Although many strategies have been developed for coating of microbial cells, limited methods are available to coat mammalian cells because most mammalian cells do not have a robust membrane or exoskeleton. Instead, they are enclosed in a lipid bilayer, which is fluidic and vulnerable to changes in its environments. It is more difficult to treat mammalian cells in vitro than microbial cells because the surfaces of mammalian cells are not protected or reinforced by a tough coat. In this work, we report a cytocompatible and degradable nanocoat for mammalian cells. Three types of mammalian cells (HeLa cells, NIH 3T3 fibroblasts, and Jurkat T cells) were individually coated within metal-polyphenol. To maintain the viability of the mammalian cells, we performed the whole processes under strictly physiological culture conditions, and carefully selected nontoxic materials.

• Bulletin of the Korean Chemical Society
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• 제35권1호
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• pp.218-224
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• 2014

In order to explore new coordination frameworks with novel designed 3-nitrophthalic acid and the same N-donor ancillary ligand, a series of novel coordination complexes, namely, $[Cd_2(3-NPA)_2(TBZ)_2(H_2O)_2]{\cdot}2H_2O$(1), $[Zn_2(3-NPA)_2(TBZ)_2]$(2), $[Zn_2O(3-NPA)(TBZ)(H_2O)]_n$(3), $[Co(3-NPA)(TBZ)(H_2O)]_n$(4) (3-$NPAH_2$ = 3-nitrophthalic acid), have been hydrothermally synthesized through the reaction of 3-nitrophthalic acid with divalent transition-metal salts in the presence of N-donor ancillary coligand (TBZ = thiabendazole). As a result of various coordination modes of the versatile 3-$NPAH_2$ and the coligand TBZ, these complexes exhibit structural diversity. X-ray structure analysis reveals that 1 and 2 are 0D molecular rings, while 3 and 4 are one-dimensional (1D) infinite chain polymers. And the weak O-H${\cdots}$O hydrogen bonds and C-H${\cdots}$O nonclassical hydrogen bonds as well as ${\pi}-{\pi}$ stacking also play important roles in affecting the final structure where complexes 1, 3 and 4 have 3D supramolecular architectures, while complex 2 has a 2D supramolecular network. Also, IR spectra, fluorescence properties and thermal decomposition process of complexes 1-4 were investigated.

• 자원환경지질
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• 제26권2호
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• pp.117-127
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• 1993

월류(月留) 은(銀)-금(金) 열수광상(熱水鑛床)의 맥상광석(脈狀鑛石)내에는 평균 34.9g/ton, 최대 145g/ton에 이르는 상당량의 게르마늄 (Ge)이 아지로다이트 (argyrodite)의 형태로 산출된다. 본 연구에서는, 전자현미분석법(電子顯微分析法)에 의하여 아지로다이트와 수반 광물의 광물화학(鑛物化學)을 검토하였고, ICP 질량(質量) 분광분석법(分光分析法)에 의하여 13개 광석시료내에 함유된 28개 원소(元素)의 정량분석(定量分析)을 수행하였다. 아지로다이트는 탄산염(炭酸鹽) 광물(鑛物)+석영(石英)+자연은(自然銀)+휘은석(煇銀石)+함은(含銀) 유염(硫鹽) 광물의조합으로 구성되는 후기 광물군(鑛物群)내에 산출되며, 이는 게르마늄의 침전(沈澱)작용이 초기 금(金) 및 후기의 은(銀) 침전(沈澱)으로 구성된 복잡한 광화작용(鑛化作用)중 후반부에서 진행되었음을 지시한다. 아지로다이트의 평균(平均) 화학조성(化學造成)은 $Ag_{7.90}(Ge_{0.76}Sn_{0.04})S_6$이며, 미량의 Cu, Fe, Sb, As, Sn 및 Zn이 함유되고, 특히 Cu에 의한 Ag, Sb에 의한 Ge의 체계적인 치환(置換)현상이 인지된다. 광석(鑛石)시료에 대한 정량분석결과, 금속원소의 침전작용(沈澱作用)은 $Fe{\rightarrow}Pb$, $Zn{\rightarrow}Cu{\rightarrow}Ag$, Sb, As, Ge의 순서로 진행되었고, 특히 Ge은 As 및 Sb와 강한 지화학적(地化學的) 친화도(親和度)를 가졌음을 규명하였다. Ge은 Cu, Pb, Zn, Mo 및 Sr과도 미약한 정(正)의 수반관계를 나타낸다. 월류(月留) 천열수계(淺熱水系)내 순환천수(循環天水)의 유입량(流入量) 증가에 기인한 냉각작용(冷却作用)에 수반하여, Ge은 주로 $175^{\circ}{\sim}210^{\circ}C$의 온도 범위에서 침전(沈澱)하였다.

• 한국환경보건학회지
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• 제14권2호
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• pp.65-71
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• 1988

In this study, the method of adsorption by activated carbon in the removal of Hg(II) ion in waste water was treated. The influence of kinds of activated carbon and effect of temperature and the influence of coexistent salt on adsorption rates, the influence of pH in the adsorption, equilibrium and adsorption of mercury from activated carbon were investigated. From the adsorption on activated carbon of mercury(II) ion in the presence of cyanide or thiocyanate ion was found that mercury(II) was easily adsorved onto the activated carbon in the form of complex artion such as Hg(CN)$_4^{2-}$, Hg(SCN)$_4^{2-}$ respectively. ZnCl$_2$ activation method had a higher adsorptive ability than steam activation method in adsorption of Hg on activated carbon. Activated carbon adsorbed iodide ion is very effective on adsorption of Hg.

• 생명과학회지
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• 제23권10호
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• pp.1246-1251
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• 2013

산업공단지역의 폐수에서 분리한 유기용매 내성 Pseudomonas sp. BCNU 154 리파아제의 최적조건은 $37^{\circ}C$, pH8로 조사되었다. BCNU 154의 crude 리파아제는 toluene에서 2시간 반응시 효소활성 약 6.01 U/ml (117.53%)로 가장 안정한 것으로 나타났다. 한편 $Ca^{2+}$, $Mg^{2+}$, $NH_4{^+}$, $Na^+$ 이온 및 triton X-100은 효소를 활성화시킨 반면에 $Ba^{2+}$, $Hg^{2+}$ 및 $Zn^{2+}$ 이온은 효소활성을 억제하였다. Pseudomonas sp. BCNU 154 리파아제는 상용 고정화 효소인 Novozym 435와 비교해서도 안정한 활성을 보였다. 그러므로 유기용매 내성 리파아제는 별도의 고정화 처리없이도 화학산업공정에서 가능성 있는 whole cell 생물촉매로서 유용할 것으로 판단된다.

• 한국토양비료학회지
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• 제51권2호
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• pp.128-141
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• 2018

Industrial complex releasing huge amounts of dusts, fumes and wastewater containing heavy metal(loid)s could be a source of heavy metal(loid)s pollution in arable soil. Heavy metal(loid)s pollution in arable soil adversely affect crops safety, subsequently human being. Hence, it is important to accurately assess the heavy metal(loid)s pollution in soil using pollution indices. The objectives of this study are 1) to compare assessment methods of heavy metal(loid)s pollution in arable soils located near industrial complex in Gyeongsang provinces and 2) to determine the relationship between concentration of plant available heavy metal(loid)s and chemical properties of soil. Soil samples were collected from 85 sites of arable lands nearby 10 industrial complex in Gyeongsang provinces. The average total concentration of all heavy metal(loid)s of the studied soils was higher than that of Korean arable soils but did not exceed the warning criteria established by the Soil Environmental Conservation Act of Korea. Only six sites of arable soils for the total concentration of As, Cu and Ni exceeded the warning criteria (As: $25mg\;kg^{-1}$, Cu: $150mg\;kg^{-1}$, Ni: $100mg\;kg^{-1}$). The contamination factor (CF) and geoaccumulation index ($I_{geo}$) of the heavy metal(loid)s in arable soils varied among the sampling sites, and the average values of As and Cd were relatively higher than that of other metals. Results of integrated indices of As and Cd in arable soils located near industrial complex indicated that some arable soils were moderately or heavily polluted. The plant available concentration of heavy metal(loid)s was negatively related to the soil pH and negative charge of soil. Available Cd, Pb, and Zn concentrations had relatively high correlation coefficient with pH and negative charge of soil when compared with other heavy metal(loid)s. Based on the above results, it might be a good soil management to control pH with soil amendments such as lime and compost to reduce phytoavailability of heavy metal(loid)s in arable soil located near industrial complex.

• 공업화학
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• 제7권6호
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• pp.1053-1060
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• 1996

Sodium amide에 의한 methyl propyl ketone과 ethyl formate의 반응으로 킬레이트 추출제의 하나인 $\beta$-ketohexanal(이하 KHA)를 합성하고, KHA-클로로포름에 의한 구리의 추출평형 실험을 통하여 추출특성을 고찰하였다. 흡광도를 측정하여 추출제 KHA의 상간 분배계수와 해리상수, KHA와 구리간 킬레이트의 안정도 상수와 분배계수 및 총괄 추출 평형상수등을 구하고, 추출기구를 구명하였다 합성한 추출제에 의한 구리의 추출율은 pH 5 이상에서 거의 100%이었고, Cu-Zn-Cd 혼합 금속으로부터 구리의 선택적 추출이 가능하였다. KHA-클로로포름에 의한 구리의 추출 화학종은 $CuR_2$였으며 추출 평형 식은 $Cu^{2+}+2{\overline{HR}}{\rightarrow}{\overline{CuR{_2}}}+2H^+$로 표시되었다.

• Bulletin of the Korean Chemical Society
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• 제31권11호
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• pp.3291-3296
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• 2010

A gelastatins (1), natural MMP inhibitors, and their hydroxamate analogues (2) in TACE enzyme evaluated for discovery of potent TACE inhibitors. We have employed molecular dynamics simulations to compute the relative free energy of hydration and binding to TACE for gelastatin (1) and its hydroxamate analogue (2). The relative free energy difference is directly described in this article using the free energy perturbation approach as a means to accurately predict the TACE inhibitor of gelastatin analogues. The results show that the good agreement between the experimental and theoretical relative free energies of binding, gelastatin hydroxamate (2) binds stronger to TACE by -3.37 kcal/mol. The desolvation energy costs significantly reduced binding affinity, hydroxamate group associated with high desolvation energy formed strong favorable interactions with TACE with more than compensated for the solvation costs and therefore led to an improvement in relative binding affinity.

• 대한화학회지
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• 제23권6호
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• pp.385-391
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• 1979

CuS-$Ag_2S$ 분말에 PVC 분말을 4 : 1 의 비율로 섞어서 눌러 만든 구리이온 선택성전극은 재현성이 좋으며 견고하고 오래 사용할 수 있는 전극임을 알았다. 이 전극을 이용하여 구리이온에 대한 감응전위를 측정한 결과 Cu(Ⅱ)용액의 농도 1.0 ${\times}$$10^{-1}M$부터 1.0 ${\times}$ $10^{-5}M$사이의 범위에서 직선관계를 나타내었고 기울기는 $298^{\circ}K$에서 Nernst의 법치긍로부터 약간 벗어난 25.0mV이었다. 이 전극을 지시전극으로 사용하여 시료용액 1.0 ${\times}$ $10^{-2} M Cu(NO_3)_2$를 0.1M NaOH 표준용액으로 침전법 적정을 할 수 있었다. 또한 이 지시전극으로 Zn(II), Mg(II), Ca(II), 등의 이온을 pH 10에서 EDTA로 적정할 수 있었고 이미 알려진 Cu-$EDTA^{2-}$이 안정도상수($-pK_{Cu-EDTA^{2-}}$=18.80)를 이용하여 칼슘 및 마그네슘의 EDTA착물의 안정도 상수 ($-pK_{Ca-EDTA^{2-}}$=10.30, $-pK_{Mg-EDTA^{2-}}$=8.00)를 결정할 수 있었다.