• 제목/요약/키워드: Isomerization

검색결과 226건 처리시간 0.027초

A Straightforward Synthesis of K-7174, a GATA-Specific Inhibitor

  • Majik, Mahesh S.;Yu, Jin-Ha;Jeong, Lak-Shin
    • Bulletin of the Korean Chemical Society
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    • 제33권9호
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    • pp.2903-2906
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    • 2012
  • K-7174, a GATA-specific inhibitor, is a putative anti-inflammatory agent that attenuates effects of inflammatory cytokines in certain cell types. An expeditious four-step synthesis of K-7174 is described in this paper. The route employs Wittig olefination and bis-alkylation of homopiperazine as the key reactions. The iodine-catalyzed isomerization of the Z-isomer results in complete conversion to the E-isomer is the highlight of our synthetic endeavors.

포도당 이성화를 위한 Alkalophilic Streptomyces sp. B-2의 균체 고정화에 관한 연구 (Studies on the Cell Immobilization of Alkalophilic Streptomyces sp. B-2 for the Glucose Isomerization)

  • 이은숙
    • 한국식품영양학회지
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    • 제11권3호
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    • pp.319-322
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    • 1998
  • 본 실험에서는 GI 활성이 높은 alkalophilic Streptomyces sp.를 사용하여 2% $ extsc{k}$-carrageenan에 균체를 고정화 균체의 효소학적 특성을 살펴보았다. pH stability는 pH가 7.5~8.5에서 GI 활성이 가장 높았으며, reaction temperature는 7$0^{\circ}C$, Co2+는 10-3M, Mg2+는 10-3M일 때 GI 활성이 가장 높은 것으로 나타났다.

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Interaction of a 22 kDa Peptidyl Prolyl cis/trans Isomerase with the Heat Shock Protein DnaK in Vibrio anguillarum

  • Kang, Dong Seop;Moon, Soo Young;Cho, Hwa Jin;Lee, Jong Min;Kong, In-Soo
    • Journal of Microbiology and Biotechnology
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    • 제27권3호
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    • pp.644-647
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    • 2017
  • Peptidyl prolyl cis/trans isomerases (PPIases) catalyze the cis/trans isomerization of peptidyl-prolyl peptide bonds preceding prolines. We investigated the protein-protein interaction between a 22 kDa PPIase (VaFKBP22, an FK506-binding protein) and the molecular chaperone DnaK derived from Vibrio anguillarum O1 (VaDnaK) using GST pull-down assays and a bacterial two-hybrid system for in vivo and in vitro studies, respectively. Furthermore, we analyzed the three-dimensional structure of the protein-protein interaction. Based on our results, VaFKBP22 appears to act as a cochaperone of VaDnaK, and contributes to protein folding and stabilization via its peptidyl-prolyl cis/trans isomerization activity.

Structure, Spectroscopic Properties and Reactions of Interstellar Molecule HC2N and Isomers :Ab initio Study

  • Park, Sung-Woo;Lee, Seong-Yul
    • Bulletin of the Korean Chemical Society
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    • 제23권11호
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    • pp.1553-1559
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    • 2002
  • Calculations are presented for the molecule HC2N and its geometrical isomers. The structures, harmonic frequencies and dipole moments are reported. The potential energy surface of the [H,C,C,N] system is investigated in detail, and the transition states, intermediate complexes, and the energies of barrier for the isomerization and dissociation reactions are computed in order to determine the reaction paths and to estimate the stability of the isomers. The barriers of isomerization among HCCN, HCNC and HNCC are computed to be rather large and dissociations of these molecules are highly endothermic, indicating that these molecules are kinetically stable. The association reactions HC + CN→HCCN, HC + NC→HCNC, and HN + CC →HNCC are barrierless and very exothermic, suggesting that they may be considered as efficient means of producing the HCCN and the isomers in the laboratory and in interstellar space.

EFFECT OF NITROGEN POSITION ON EXCITED STATE PROPERTIES OF 1-(9- ANTHRYL )-2-(n-QUINOLINYL)ETHENES

  • Shin, Eun-Ju
    • Journal of Photoscience
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    • 제6권2호
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    • pp.61-65
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    • 1999
  • The fluorescence properties and photoisomerization behavior of 1-(9-anthryl)-2-(n-quinolinyl)ethene (n-AQE, n=2-4) have been investigated in various solvents. t-3-AQE is strongly fluorescent, but does not accomplish photoisomerization, similar to parent hydrocarbon compound, t-1-(9-anthryl)-2-phenylethene (t-9-APE) or t-1-(9-anthryl)-2-(1-naphthyl)ethene (t-1-ANE). Fluorescence and photoisomerization oft-2-AQE and t-4-AQE are strongly affected by solvent polarity. Dependence of fluorescence quantum yield on the solvent polarity is moderate for t-2-AQE and large for t-4-AQE. In nonpolar solvent (in n-hexane), they exhibit relatively strong fluorescence, but do not isomerize to cis isomer on irradiation, even if inefficient isomerization is observed for t-4-AQE. However, as solvent polarity increases, their fluorescences become weak with efficient photoisomerization to corresponding cis isomer. Intramolecular charge-transfer excited state is presumed to contribute to photoisomerization. The S$_1$ decay parameters were found to be solvent-dependent due to the charge-transfer character of lowest S$_1$ state. In polar solvents, the activation barrier to twisting is reduced enhancing the isomerization of r-2-AQE and t-4-AQE in the singlet manifold.

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