• Journal of Microbiology and Biotechnology
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• 제29권3호
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• pp.373-381
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• 2019

Site-directed mutagenesis was employed to generate five different triple point mutations in the double mutant (C295A/I86A) of Thermoanaerobacter ethanolicus alcohol dehydrogenase (TeSADH) by computer-aided modeling with the aim of widening the small alkyl-binding pocket. TeSADH engineering enables the enzyme to accept sterically hindered substrates that could not be accepted by the wild-type enzyme. The underline in the mutations highlights the additional point mutation on the double mutant TeSADH introduced in this work. The catalytic efficiency ($k_{cat}/K_M$) of the ${\underline{M151A}}$/C295A/I86A triple TeSADH mutant for acetophenone increased about 4.8-fold higher than that of the double mutant. A 2.4-fold increase in conversion of 3'-methylacetophenone to (R)-1-(3-methylphenyl)-ethanol with a yield of 87% was obtained by using ${\underline{V115A}}$/C295A/I86A mutant in asymmetric reduction. The ${\underline{A85G}}$/C295A/I86A mutant also produced (R)-1-(3-methylphenyl)-ethanol (1.7-fold) from 3'-methylacetophenone and (R)-1-(3-methoxyphenyl)-ethanol (1.2-fold) from 3'-methoxyacetophenone, with improved yield. In terms of thermal stability, the ${\underline{M151A}}$/C295A/I86A and ${\underline{V115A}}$/C295A/I86A mutants significantly increased ${\Delta}T_{1/2}$ by $+6.8^{\circ}C$ and $+2.4^{\circ}C$, respectively, with thermal deactivation constant ($k_d$) close to the wild-type enzyme. The ${\underline{M151A}}$/C295A/I86A mutant reacts optimally at $70^{\circ}C$ with almost 4 times more residual activity than the wild type. Considering broad substrate tolerance and thermal stability together, it would be promising to produce (R)-1-(3-methylphenyl)-ethanol from 3'-methylacetophenone by ${\underline{V115A}}$/C295A/I86A, and (R)-1-phenylethanol from acetophenone by ${\underline{M151A}}$/C295A/I86A mutant, in large-scale bioreduction processes.

• Bulletin of the Korean Chemical Society
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• 제23권1호
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• pp.65-70
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• 2002

We have evaluated the specific hydroxyl group-solvent and carbonyl group-solvent interactions by using an Alltima C18 stationary phase and by measuring the retention data of carefully selected solutes in 60/40, 70/30, and 80/20(v/v%) acetonitrile/water eluents at 25, 30, 35, 40, 45, and 50 oC. The selected solutes are phenol, acetophenone, alkylbenznes(benzene to hexylbenznene), 4 positional isomers of phenylbutanol, 5-phenyl-1-pentanol, 3 positional isomers of alkylarylketone derived from butylbenzene, and 1-phenyl-2-hexanone. The magnitudes of hydroxyl group-acetonitrile/water specific interaction enthalpies are larger than those of carbonyl group-acetonitrile/water specific interaction enthalpies in general while the magnitudes of carbonyl group-methanol/water specific interaction enthalpies are larger than those of hydroxyl group-methanol/water specific interactions. We observed clear discrepancies in functional group-solvent specific interaction among positional isomers. The variation trends of solute transfer enthalpies and entropies with mobile phase composition in the acetonitrile/water system are much different from those in the methanol/water system. The well-known pocket formation of acetonitrile in aqueous acetonitrile mixtures has proven to be useful to explain such phenomena.

• 한국의류산업학회지
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• 제9권1호
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• pp.113-118
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• 2007

It is well recognized that the wicking of liquids in a textile fabric takes place mainly through a capillary system composed of the individual fibers. Considering typical dyeing stages, it is thought that a high dye uptake on the fabric probably depends on the wickability. Three kinds of barely water soluble ketones, acetophenone(A), 2-pentanone(2P) and 3-pentanone(3P) were separately dissolved in methanol(M) and then each was mixed with aqueous solution of C. I. Red Acid 114. Wicking heights of dyeing solutions were measured under such conditions that the effect of gravity was negligible. The result could be graphed as a series of straight lines having the form s = $kt^{1/2}$, where s was distance traveled by the solutions, t was time, and k was slope of the line. The surface tension(${\gamma}$) of the ketones had more signifcant effect on the wickability compared to the viscosity(${\eta}$) of them. The greater wickability resulted in the higher dye uptake on the fabric and the order of wickabilty was equal to that of the surface tension(${\gamma}$) and dye uptake on the fabric, A>3P>2P>M.

• Bulletin of the Korean Chemical Society
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• 제26권4호
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• pp.563-568
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• 2005

The Pt/C and Pd/C catalysts were prepared from conventional chloride precursors by adsorption or precipitation-deposition methods. Their activities for hydrogenation reactions of cyclohexene and acetophenone were compared with those of commercial catalysts. The Pt/C and Pd/C catalysts obtained from the adsorption procedure reveal higher hydrogenation activity than commercial catalysts and the catalysts prepared by the precipitation-deposition method. Their improved performances are attributed to the decreased metal crystallite sizes of Pt or Pd formed on the active carbon support upon the adsorption of the precursors probably due to the same negative charges of the chloride precursor and the carbon support. Under the preparation conditions studied, the reduction of the supported catalysts using borohydrides in liquid phase is superior to a gas phase reduction by using hydrogen in the viewpoint of particle size, hydrogenation activity and convenience.

• 센서학회지
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• 제21권1호
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• pp.13-20
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• 2012

Due to its high conductivity, pyrylium has been frequently used in electron transfer reactions or in the synthesis of various organic materials. It has also been used as a sensor material. Traditionally, the compounds have been synthesized using various methods; mostly in a multiple steps. In this study, two pyrylium salts, 2, 6-di-(4'-methylphenyl) pyrylium fluoroborate and perchlorate were synthesized. The synthesis of these products was confirmed by 1H-NMR, LC/TOF-MS and FT-IR analyses while their photo-properties were analyzed using UV/VIS spectrophotometry. In addition, the electron transfer capacities of the salts were analyzed with a conductivity meter, it was found that their electron conductivities were high. When the synthesized compounds were dissolved in acetone, a green fluorescent material was observed to form. The fluorescent material can be used as a sensitizer in the electrical industry.

• 생약학회지
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• 제47권3호
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• pp.226-231
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• 2016

The present GC-MS analysis elucidated the composition of the essential oil obtained from the herb of Elsholtzia ciliata(Lamiaceae). Overall, the content of monoterpenes was higher than that of sesquiterpenes. Monoterpenes rich in this oil were carvone (peak area, 26.180%), camphor (2.304%), borneol (9.974%), dihydrocarveol (3.296%), ${\alpha}$-citral (=geranial, 4.025%), geranic acid (2.961%), while sesquiterpenes occupying relatively higher percentage were ${\alpha}$-humulene (0.918%), (-)-spathulenol (0.974%), ${\alpha}$-caryophyllene oxide (2.014%), globulol (1.362%), ${\beta}$-caryophyllene oxide (0.750%). The components characterizing this oil were 1-octen-3-ol, acetophenone, and butylated hydroxytoluene. The $IC_{50}$ of this oil on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) were $42.37{\mu}g/ml$ and $121.34{\mu}g/ml$, respectively, suggesting that the essential oil of E. ciliata may be active on the memory loss of patients suffering from Alzheimer's disease.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1608-1610
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• 2000

In this work, the effect of annealing on physical and electrical properties of XLPE cable insulation was investigated. One sample was non-annealed and the other two samples were treated under air circulated oven at 80$^{\circ}C$ for five and ten days. In the DSC patterns of annealed specimen, new peaks appeared at near 80$^{\circ}C$ as a proof of thermal history. The degree of crystallinity increased by annealing effect. In the FT-IR spectrums, the change of absorbances to acetophenone and cumyl alcohol were observated according to the radial direction of cable insulation. They slowly diffused into both semi-conductive layer of the cable in proportion to annealing time and lastly led to near equilibrium state through cable insulation. The AC breakdown strength did not increased but the values were stabilized by effects of crystallinity and diffusion of by-products.

• 대한화학회지
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• 제28권6호
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• pp.425-432
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• 1984

難染性纖維인 폴리프로필렌用 反應性染料를 開發하기 위하여 反應部位로서 카르벤을 染料에 生成케하여 폴리프로필렌의 C-H結合에 揷入反應을 시켜 堅固한 染着物을 얻을 수 있었다. 反應性카르벤染料의 前驅體로서 알데히드係, 메틸케톤係 및 페닐케톤係 反應性染料를 合成하고 카보닐基에 토실히드라진 및 부틸리튬을 各各 作用하여 各種染料의 토실히드라존리튬鹽을 만들어 폴리프로필렌상에서 加熱分解시킴으로써 染料分子에 生成된 카르벤이 폴리프로필렌에 共有結合을 하여 染着하였다. 여기에서 合成한 各種 카르벤染料들은 카르벤이 生成되는 隣接位에 있는 置換基의 種類와 位置에 따라 反應性에 差異點을 나타내었다. 특히 페닐케톤係 反應性染料가 反應性이 優秀하였으며 이들 페닐케톤係 反應性染料의 前驅體中에서도 클로로基를 가지는 클로로아미노벤조페논으로부터 合成한 染料가 他에 비해 反應性이 良好하였다.

• Archives of Pharmacal Research
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• 제14권4호
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• pp.290-294
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• 1991

For the determination of peripheral COMT activity, we synthesized $[2-^{14}C]-3',4'-dihydroxyacetophenone([^{14}C]-DHAP)$, a model substrate closely related to catecholamines, which cannot be attacked by monoamine oxidase. After i.v.-injection of $[^{14}C]-DHAP$ in living animals, only 3',4'-dihydroxy-acetophenone (3',4'-DHAP) and 3'-methoxy-4'-hydroxyacetophenone (3'-MHAP) were detected in blood by thin layer radio chromatography. It could be speculated that 3',4'-DHAP was primarily O-methylated by COMT, followed by subsequent conjugations. The concentration of 3',4'-DHAP, a substrate for COMT, in blood at 5 min after injection of $[^{14}C]-DHAP$, were similar in all animals. The rate of 3'-MHAP formation can be therefore used as an indicator for peripheral COMT activity. The velocity of methylation in 15 min after i.v.-administration of $[^{14}C]-DHAP$ was $0.28\;{\mu}g/ml{\cdot}min$. From these results, 3',4'-DHAP was shown to be used as an appropriate substrate to determine the COMT activity in vivo.

• 대한화학회지
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• 제59권3호
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• pp.215-224
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• 2015

Unsymmetrical tetradentate Schiff base N-(2-hydroxy-5-methylacetophenone)-N'-(2-hydroxy acetophenone) ethylene diamine (H₂L) and its complexes with Cr(III), Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) have been synthesized and characterized by elemental analyses, magnetic susceptibility measurements, IR, electronic spectra and thermogravimetric analyses. ¹H, ¹³C-NMR and FAB Mass spectra of ligand clearly indicate the presence of OH and azomethine groups. Elemental analyses of the complexes indicate that the metal to ligand ratio is 1:1 in all complexes. Infrared spectra of complexes indicate a dibasic quadridentate nature of the ligand and its coordination to metal ions through phenolic oxygen and azomethine nitrogen atoms. The thermal behavior of these complexes showed the loss of lattice water in the first step followed by decomposition of the ligand in subsequent steps. The thermal data have also been analyzed for the kinetic parameters by using Horowitz-Metzger method. The dependence of the electrical conductivity on the temperature has been studied over the temperature range 313-403 K and the complexes are found to show semiconducting behavior. XRD and SEM images of some representative complexes have been recorded. The antimicrobial activity of the ligand and its complexes has been screened against various microorganisms and all of them were found to be active against the test organisms. The Fe(III) and Ni(II) complex have been tested for the catalytic oxidation of styrene.