• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1996년도 춘계학술대회
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• pp.183-183
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• 1996

Bacteriophage T4 endonuclease V initiates the repair of ultraviolet (UV)-induced pyrimidine dimer photoproducts in duplex DNA. The mechanism of DNA strand cleavage involves four sequential stens: linear diffusion along dsDNA, pyrimidine dimer-specific binding,l pyrimidine dimer-DNA glycosylase activity, and Af lyase activity. Although crystal structure is known for this enzyme, solution structure has not been yet known. In order to elucidate the solution structure of this enzyme NMR spectroscopy was used. As a basis for the NMR peak assignment of the protein, HSQC spectrum was obtained on the uniformly $\^$15/N-labeled T4 endonuclease V. Each amide peak of the spectrum were classified according to amino acid spin systems by interpreting the spectrum of $\^$15/N amino acid-specific labeled T4 endonuclease V. The assignment was mainly obtained from three-dimensional NMR spectra such as 3D NOESY-HMQC, 3D TOCSY-HMQC. These experiments were carried out will uniformly $\^$15/N-labeled sample. In order to assign tile resonance of backbon atom, triple-resonance theree-dimensional NMR experiments were also performed using double labeled($\^$15/N$\^$13/C) sample. 3D HNCA, HN(CO)CA, HNCO, HN(CA)HA spectra were recorded for this purpose. The results of assignments were used to interpret the interaction of this enzyme with DNA. HSQC spectrum was obtained for T4 endonuclease V with specific $\^$15/N-labeled amino acids that have been known for important residue in catalysis. By comparing the spectrum of enzyme*DNA complex with that of the enzyme, we could confirm the important role of some residues of Thr, Arg, Tyr in activity. The results of assignments were also used to predict the secondary structure by chemical shift index (CSI).

• 대한화학회지
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• 제40권6호
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• pp.394-400
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• 1996

결합성 사슬이합체를 형성할 수 있는 올리고펩티드-$(HPPHPPP)_n$-(H: 소수성 아미노산, P: 친수성 아미노산)는 온도, 수소이온 농도, 이온세기, 변성시약 등에 의해 구조적인 변화가 가능하다. 본 연구에서는 변성시약과 온도에 의한 올리고펩티드의 전이 현상을 이론적으로 고찰하였다. 사슬이합체로는 올리고펩티드20R, 변성시약으로는 구아니듐-염산을 사용하였다(20R에는 사슬 내의 정전기적 반발력이 10개가 존재하고, 사슬사이의 정전기적 반발력이 10개가 존재한다). 변성 시약에 의한 올리고펩티드의 나선에서 코일로의 전이는 급격한 것으로 보아, 변성이 일어나는 전이상태에서 올리고펩티드들은 완전한 나선구조와 무질서한 코일구조로만 되어있다. 반면에 온도에 의한 전이는 변성시약에 의한 전이보다 완만하게 일어난다. 낮은 온도에서 긴 나선 구조를 가지는 올리고펩티드가 짧은 나선 구조를 가지는 것보다 다량으로 존재한다. 온도가 증가할수록 부분적으로 변성된 분자들의 몰분율이 증가하여, 전이가 일어나는 온도에서 부분적으로 변성된 올리고펩티드가 널리 분포되어 있다.

• 한국인쇄학회지
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• 제16권2호
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• pp.61-74
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• 1998

Some photopolymer, poly(vinyl cinnamoyl acetate)(PVCiA) was synthesized by esterification of polymer(vinyl alcohol)(PVA) with monochloroacetic acid, followed by reaction poly(vinyl monochloroacetate)(PVAhA) and potassium cinnamate. When esterification of PVA with monochloroacetic acid was reacted in the dimethyl sulfoxide(DMSO), in the synthesis of PVChA, it is very good yield and the successive cinnamoyl acetoxyl esterification of PVCiA can be successfully synthesized. But PVCiA is low photosensitive polymer if net added photosensitizing dyes. Here, we synthesized photosensitizing dyes.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2010년도 춘계학술발표회 논문집
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• pp.79-92
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• 2010

In the presence of laccase, generation of monomeric aromatic acids from nonphenolic lignin model dimer veratrylglycerol-$\beta$-vanillate ether (VVE) was observed. The addition of acetovanillone (AV) or acetosyringone (AS) intensified this process, i.e. transformation was more extensive than in the experiments omitting mediators. Among the products isovanillic (IA) and vanillic (VA) acids were identified.

• BMB Reports
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• 제32권6호
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• pp.594-598
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• 1999

The Jun and Fos families of eukaryotic transcription factors form heterodimers capable of binding to their cognate DNA enhancer elements. We are interested in searching for inhibitors or antagonists of the binding of the Jun-Fos heterodimer to the activator protein-1 (AP-1) site. The basic-region leucine zipper (bZIP) domain of c-Fos was expressed as a fusion protein with glutathione S-transferase, and allowed to form a heterodimer with the bZIP domain of c-Jun. The heterodimer was bound to glutathione-agarose, to which were added radiolabeled AP-1 nucleotides. After thorough washing, the gel-bound radioactivity was counted. The assay is faster than the coventional electrophoretic mobility shift assay because the gel electrophoresis step and the autoradiography step are eliminated. Moreover, the assay is very sensitive, allowing the detection of picomolar quantities of nucleotides, and is not affected by up to 50% dimethylsulfoxide, a solvent for hydrophobic inhibitors. Curcumin and dihydroguaiaretic acid, recently known inhibitors of Jun-Fos-DNA complex formation, were applied to this Jun-GST-fused Fos system and revealed to decrease the dimer-DNA binding.

• 대한핵의학회지
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• 제28권2호
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• pp.167-171
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• 1994

Ethylcystein dimer (ECD) was synthesized by dimerizatlon of L-thiazolidine-4-carboxylic acid in liquid ammania with sodium metal and successive esterification in ethanolic solution of hydrogen chlorde. The purified product was labeled with $^{99m}Tc$ in the presence of sodium glucarate(pH= 5.6) and stannous chloride. Best result was obtained from the preparation con sisting of 0.1mg ECD, $40{\mu}l$ of 0.4M sodium glucarate (pH=5.6), and $20{\mu}g$ of stannous chloride. The labeling efficiency was 90% with previous condition. The labeled $^{99m}Tc$-ECD was stable at least for 3 hours in PBS(pH=7.4) at room temperature. About 10mCi of $^{99m}Tc$-ECD was injected to normal volunteer, and SPECT image of brain was obtained by triple head camera 10 minutes after inection. The image showed similar distribution of radioactivity in brain with that of HMPAO image.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2003년도 정기총회 및 학술발표회
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• pp.26-26
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• 2003

The backbone dynamics of ketosteroid isomerase, a homodimeric enzyme with 125 amino acid residues per subunit, has been studied in the presence/absence of a steroid ligand and 5％ trifluoroethanol (TFE) by $^{15}$ M relaxation measurements. The relaxation data were analyzed using the model-free formalism to extract the model-free parameters (S$^2$, $\tau$$_{e}$, and R$_{ex}$ ). The results show that a large number of the residues, particularly those involved in the dimer interaction, exhibit reduced order parameters (S$^2$) in the steroid-bound enzyme, indicating the increased high-frequency (pico- to nanosecond) motions in the interface region upon ligand binding. The results also show that that the presence of 5 ％ TFE in free enzyme causes little change or slight increase in the order parameters for a number of residues in the dimer interface region. However, the majority of the residues in free enzyme exhibit reduced order parameters in the presence of 5 ％ TFE, indicating that the increase in entropy is partially responsible for the increased stability of KSI by 5％ TFE.E.E.

• Bulletin of the Korean Chemical Society
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• 제31권4호
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• pp.941-948
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• 2010

Ab initio and density functional theory methods have been employed to study all theoretically possible conformers of fluoroacetic acid. Molecular geometries and energetic of cis and trans monomers and cis dimers in gaseous phase have been obtained using HF, B3LYP and MP2 levels of theory, implementing 6-311++G(d,p) basis set. It was found that cis rotamers are more stable. In addition, it was found that in comparison with acetic acid the strength of hydrogen bonding in fluoroacetic acid decreased. The infrared spectrum frequencies and the vibrational frequency shifts are reported. Natural population and atom in molecule analysis performed to predict electrostatic interactions in the cyclic H-bonded complexes and charges. The proton transfer reaction is studied and activation energy is compared with acetic acid proton transfer reaction.

• 공업화학
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• 제16권5호
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• pp.684-688
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• 2005

산도가 각기 다른 양성자산(HF, HCI, HBr, HI, $H_2SO_4$)의 수용액내에서 아닐린을 중합하였다. 이때 산도(pH)와 상대이온(counter ion)의 반응성에 따른 반응속도에 관하여 조사하였다. 반응속도에 대한 양성자산의 영향을 조사하기 위하여, open-circuit potential을 측정하였다. 그 결과 HF 수용액내에서 중합속도가 가장 느리게 나타났고, HI 수용액내에서는 중합반응이 진행되지 않았으며, 이러한 결과들을 산도(pH)와 산화력과의 관계로 설명하였다. 양성자산의 종류에 따라 dimer들의 생성비율도 각기 다르게 나타났으며, 이러한 결과들을 상대이온(음이온)의 친핵성도 (nucleophilicity), 용매화효과 및 이동도의 영향으로 설명하였다.

• 한국식품과학회지
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• 제24권1호
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• pp.37-41
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• 1992

고형상의 모델시스템에서 베타-카로틴과 알파-토코폐롤의 산화에 미치는 리폭시게나아제, 리놀레산, 수분활성도의 영향에 대해 검토하였다. 리놀레산 존재하에서 리폭시게나아제에 의한 베타-카로틴과 알파-토코페롤의 산화반응은 높은 수분활성도에서 잘 일어났으며 반응 48시간 경과 후에는 베타-카로틴의 경우 초기함량에 대해 19% 잔존량만을 보였고 알파-토코페롤은 5%를 나타내어 현저히 감소되는 경향을 보였다. 이와같이 동일 조건에서 알파-토코페롤은 베타-카로틴보다 더 많은 감소량을 보여 peroxy radical과의 반응성이 베타-카로틴보다 뛰어난 것을 알 수 있었다. 또한 베타-카로틴의 농도가 높을수록 베타-카로틴의 산화속도도 비례적으로 빨라지는 양상을 보였다. 그러나 스펙트럼상으로 볼 때 베타카로틴의 산화로 인한 최대파장의 이동은 일어나지 않았다. 알파-토코페롤의 산화생성물로는 ${\alpha}-tocopheryl\;quinone$과 ${\alpha}-tocopheryl\;dimer$가 검출되었으며 주요 산화생성물은 ${\alpha}-tocopheryl\;quinone$으로서 반응경과에 따라 크게 증가하였다. 또한 이들 산화생성물은 리폭시게나아제와의 반응에 의해 그 함량이 훨씬 많음을 나타내었다.