• Journal of Microbiology and Biotechnology
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• 제23권11호
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• pp.1544-1553
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• 2013

Despite the importance of acetate kinase in the metabolism of bacteria, limited structural studies have been carried out on this enzyme. In this study, a three-dimensional structure of the Escherichia coli acetate kinase was constructed by use of molecular modeling methods. In the next stage, by considering the structure of the catalytic intermediate, trifluoroethanol (TFE) and trifluoroethyl butyrate were proposed as potential inhibitors of the enzyme. The putative binding mode of these compounds was studied with the use of a docking program, which revealed that they can fit well into the enzyme. To study the role of these potential enzyme inhibitors in the metabolic pathway of E. coli, their effects on the growth of this bacterium were studied. The results showed that growth was considerably reduced in the presence of these inhibitors. Changes in the profile of the metabolic products were studied by proton nuclear magnetic resonance spectroscopy. Remarkable changes were observed in the quantity of acetate, but other products were less altered. In this study, inhibition of growth by the two inhibitors as reflected by a change in the metabolism of E. coli suggests the potential use of these compounds (particularly TFE) as bacteriostatic agents.

• 대한화학회지
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• 제19권3호
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• pp.149-155
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• 1975

플라스틱 결정체인 피발산의 temperature-dependent wide-line NMR line width, second monent 및 spin-lattice relaxation times 의 결과는 이 결정체의 특이한 운동학적 성질 및 수소결합에 기인된 것으로 해석된다. 이 분자의 운동학적 성질은 $C_3-C_3'$ reorientation 및 self-diffusion 으로 구성 되었음을 확인했다. Wide-line NMR 연구결과는 또한 Pople-Karasz 융해설과 비교검토되었고, 이 이론과의 차이점은 피발산의 수소결합에 기인되었음을 알아냈다.

• 대한환경공학회지
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• 제27권1호
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• pp.11-16
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• 2005

한강을 상수원으로 하는 재래식 정수처리 시설의 각 단위공정으로부터 휴믹물질(HS; humic substances)을 분리하여 작용기 분포, 화학적 조성, FT-IR(Fourier transform infrared) 그리고 $^1H-NMR$(proton nuclear magnetic resonance) 스팩트럼을 분석하여 구조 및 화학적 특성을 평가하였다. HS의 농도분포는 정수처리 동안 47.2%에서 26.4%(0.97 mgC/L에서 0.54 mgC/L)로 단계적으로 감소하였다. HS 중 페놀기(phenolic groups)의 농도분포는 정수처리 동안 60.5%에서 21.8%($12.2{\sim}6.0\;{\mu}M/L$ as phenolic-OH)로 점차 감소하였으며, 카르복실기(carboxylic groups)의 경우 전염소처리 이후 39.5%($7.9\;{\mu}M/L$ as COOH)에서 46.9%($10.6\;{\mu}M/L$ as COOH)로 증가하였지만 응집 침전 그리고 모래여과 이후 34.2%($9.4\;{\mu}M/L$ as COOH)까지 단계적으로 감소하였다. 또한 원소분석과 FT-IR 및 $^1H-NMR$ 분석결과 정수처리 공정을 거치면서 카르복실기의 분율이 증가하고 방향족에 대한 지방족 양성자의 비($P_{Al}/P_{Ar}$)가 증가하는 것으로 조사되어 상대적으로 지방족 화합물의 물질분율이 증가하는 것을 확인하였다.

• 대한화학회지
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• 제28권5호
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• pp.335-341
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• 1984

${\alpha},{\beta}$-불포화 알데히드의 아세탈은 브롬화 방향족화합물들과 팔라듐 촉매와 트리에틸아민 존재하에서 쉽게 반응하여 방향족의 conjugated enals을 생성하였다. 불포화 아세탈로서 acrolein diethyl acetal과 methacrolein diethyl acetal을 사용하여 이들을 메틸기와 이소프로필기로 치환된 브롬화 방향족화합물들과 $100^{\circ}C$에서 반응시킨 뒤 생성물들을 옥살산 수용액으로 처리하여 방향족의 conjugated enals를 합성하였다. o-bromotoluene과 methacrolein diethyl acetal과의 반응을 제외하고는 모두 60% 이상의 좋은 수득율을 얻을 수 있었으며 생성물의 구조는 proton NMR과 IR스펙트럼으로 확인하였다. 3-bromopropenal dimethyl acetal 및 (E)-3-bromo-2-methylpropenal diethyl acetal을 할로겐화 비닐화합물의 반응 부위로 하고 1-알켄과 ethyl acrylate등을 올레핀 반응 부위로 하는 반응물들의 역조합(reverse combination)에 의하여 지방족의 2,4-dienals를 50% 이상의 수득율로 합성 할 수 있다.

• 한국식품과학회지
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• 제25권2호
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• pp.148-153
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• 1993

최근 sucrose polyesters(SPE)와 더불어 유지대체 물질로서의 사용이 검토되고 있는 glucitol fatty acid polyesters(GPE)를 합성한 후, 화학적 구조 및 상대적 에스테르 분포에 따른 치환도를 조사하였다. 본 연구에서 합성한 GPE는 순상 HPLC에 의해 단일 에스테르 그룹으로 분리되었으며, 분리된 에스테르 그룹의 치환도는 6으로서 GPE 전체가 glucitol fatty acid hexaester임을 알 수 있었다. GPE의 IR 스펙트럼에서 $1747\;cm^{-1}$에 나타나는 흡수대는 GPE 분자내에 glucitol과 지방산을 연결하고 있는 에스테르 결합이 존재함을 보여주었다. GPE는 H-NMR 스펙트럼에서는 glucitol의 hydroxyl proton의 시그널이 존재하지 않음을 볼 때 glucitol의 모든 수산기가 지방산과의 에스테르 결합에 참여하고 있음을 알 수 있었다. 또한 GPE의 H-NHR 스펙트럼을 정량적으로 해석한 결과는 수산기가(hydroxyl value) 측정에 의해 결정된 GPE의 치환도와 일치하였다. 이상의 결과를 종합하여 볼 때 본 연구에서 합성한 GPE는 glucitol fatty acid hexaester임이 확인되었고 향후 유지대체물질로서 사용되어질 가능성을 지닌 것으로 생각되었다.

• 한국자기공명학회논문지
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• 제4권1호
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• pp.19-28
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• 2000

Authors evaluated alterations of observable metabolite ratios between the cerebral lesion and the contralateral region related to the clinical symptomatic side in levodopa-treated Parkinson's disease (PD) and investigated correlation between age in patients with PD and metabolite ratios of the lesion. Patients with levodopa-treated PD (n = 54) and age-matched normal controls (n = 15) underwent magnetic resonance spectroscopy (MRS) examinations using a stimulated echo acquisition mode (STEAM) pulse sequence that provided 2$\times$2$\times$2 cm3 volume of interest in the selected regions of substantia nigra (SN) and putamed-globus pallidus (PG). To evaluate dependence of metabolite ratios on age, we divided into two groups (i.e., younger and older age). We quantitatively measured N-acetylaspartate (NAA), creatine (Cr), choline-containing compounds (Cho), inositols (Ins), and the sum of glutamate (Glx) and GABA levels and obtained proton metabolite ratios relative to Cr using a Marquart algorithm. Compared with the contralateral region, a significant neuronal laterality of the NAA/Cr ratio in the lesion of SN related to the clinical symptomatic side was established (P = 0.01), but was not established in the lesion of PG (P = 0.24). Also, Cho/Cr ratio tended toward significance in the lesion of SN (P = 0.07) and was statistically significant in the lesion of PG(P = 0.01). Compared with that in the younger age group, NAA/Cr ratio in the older age was decreased in the lesion of SN (P = 0.02), while NAA/Cr ratio was not statistically significant in the lesion of PG ( P = 0.21). Significant metabolic alterations of NAA/Cr and Cho/Cr ratios might be closely related with functional changes of neuropathological process in SN and PG of levodopa treated PD and could be a valuable finding for evaluation of the PD. A trend of NAA/Cr reduction, being statistically significant in older patients, could be indicative of more pronounced neuronal damage in the SN of the progressive PD.

• Bulletin of the Korean Chemical Society
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• 제33권5호
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• pp.1647-1652
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• 2012

With the objective to design and synthesis of Schiff's base symmetrical liquid crystal dimmers and to study the effect of molecular structure variation ($o-ortho$, $m-meta$, $p-para$) and change in alkoxy terminal chain length on mesomorphic properties of liquid crystals, We have synthesized Schiff base dimers from dialdehyde derivative containing 2-hydroxy-1,3-dioxypropylene as short spacer with aniline derivatives having different lengths of terminal alkoxy chains ($n$ = 5, 7, 9). The chemical structure of the final products was characterized by proton nuclear magnetic resonance ($^1H$ NMR) spectroscopy and fourier transform infrared (FT-IR) spectroscopy. The mesomorphic properties and optical textures of the resultant dimers were characterized by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). The existence of smectic A phase transition was confirmed by the observation of batonnets and fan shaped textures in optical microscopy when compound were heated from crystalline phase. All of the dimers of this series, with the exception of $\mathbf{2S_5}$ -ortho, -meta, -para, were thermotropic liquid crystal. The compound $\mathbf{2S_9}$ -meta was monotropic, while the rest were enantiotropic. It was found that the change in terminal alkoxy chain length has pronounced effect on the mesomorphic properties. The temperature range of smectic A phase window widens with increasing alkoxy chain length.

• 농업과학연구
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• 제45권3호
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• pp.455-461
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• 2018

Deoxynivalenol (DON), a Fusarium mycotoxin, causes health hazards for both humans and livestock. Therefore, the aim of this study was to investigate the metabolic profiles of the liver, serum, and urine of piglets fed DON using proton nuclear magnetic resonance ($^1H-NMR$) spectroscopy. The $^1H-NMR$ spectra of the liver, serum, and urine samples of the piglets provided with feed containing 8 mg DON/kg for 4 weeks were aligned and identified using the icoshift algorithm of MATLAB $R^2013b$. The data were analyzed by multivariate analysis and by MetaboAnalyst 4.0. The DON-treated groups exhibited discriminating metabolites in the three different sample types. Metabolic profiling by $^1H-NMR$ spectroscopy revealed potential metabolites including lactate, glucose, taurine, alanine, glycine, glutamate, creatine, and glutamine upon mycotoxin exposure (variable importance in the projection, VIP > 1). Forty-six metabolites selected from the principal component analysis (PCA) helped to predict sixty-five pathways in the DON-treated piglets using metabolite sets containing at least two compounds. The DON treatment catalyzed the citrate synthase reactions which led to an increase in the acetate and a decrease in the glucose concentrations. Therefore, our findings suggest that glyceraldehyde-3-phosphate dehydrogenase, citrate synthase, ATP synthase, and pyruvate carboxylase should be considered important in piglets fed DON contaminated feed. Metabolomics analysis could be a powerful method for the discovery of novel indicators underlying mycotoxin treatments.

• 폴리머
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• 제34권1호
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• pp.69-73
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• 2010

Effects of reaction time and temperature on the isomerization and dehydrobromination reactions of brominated butyl rubber were investigated. The structural composition of brominated butyl rubber was determined by Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance spectroscopy($^1H$-NMR), Density functional theory (DFT) was used to study on the isomerization and dehydrobromination mechanisms of model compounds. The geometries for model compounds of 3-bromo-5,5,7,7-tetramethyl-2(2',2',4',4'-tetramethyl)pentyl-1-octylene (3BrOE), 1-bromo-5,5,7,7-tetramethyl-2(2',2',4',4'-tetramethyl)pentyl-2-octylene (1Br2OE) and 5,5,7,7-tetramethyl-2(2',2', 4',4'-tetramethyl)pentyl-1,3-octadiene (CD) had been optimized by using density functional theory at B3LYP/3-21G and B3LYP/6-31G levels. The predicted energy of 3BrOE lies higher than that of 1Br2OE which suggests that 1Br2OE configuration is more stable than the 3BrOE configuration. Compared with the energy barrier, the pathway of dehydrobromination is less competitive than that of isomerization. This is qualitatively consistent with the experimental results.

• Elastomers and Composites
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• 제50권2호
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• pp.110-118
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• 2015

In this study, diethylaminoethyl methacrylate-styrene-butadiene terpolymer (DEAEMA-SBR), in which diethylaminoethyl methacrylate (DEAEMA) was introduced to the SBR molecule as a third monomer, was synthesized by cold emulsion polymerization. It is expected that amine group introduced to a rubber molecule would improve dispersion of silica by the formation of hydrogen bond (or ionic coupling) between the amine group and silanol groups of silica surface. The chemical structure of DEAEMA-SBR was analyzed using proton nuclear magnetic resonance spectroscopy (H-NMR), Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC) and differential scanning calorimetry (DSC). Then, various properties of DEAEMA-SBR/silica composite such as crosslink density, bound rubber content, abrasion resistance, and mechanical properties were evaluated. As a result, bound rubber content and crosslink density of DEAEMA-SBR/silica compound were higher than those of the SBR 1721 composite. Abrasion resistance and moduli at 300% elongation of the DEAEMA-SBR/silica composite were better than those of SBR 1721 composite due to the high bound rubber content and crosslink density. These results are attributed to high affinity between DEAEMA-SBR and silica. The proposed study suggests that DEAEMA-SBR can help to improve mechanical properties and abrasion resistance of the tire tread part.