• Title/Summary/Keyword: Metalloenzyme

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Synthesis of 2'-Hydroxydihydrochalcone from Flavone

  • Kim, Mi-Hyang;Shin, Bok-Kyu;Won, Dong-Ho;Han, Jae-Hong
    • Journal of Applied Biological Chemistry
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    • v.50 no.2
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    • pp.85-87
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    • 2007
  • To establish the synthetic method for dihydrochalcones as an important bioactive compounds, 2'-hydroxydihydrochalcone has been synthesized from the reduction of flavone in 20% yield. Flavone with five equivalents of ammonium formate in the presence of Pd/C in methanol under $N_2$ atmosphere produced the C-ring opened product. It was characterized by UV-VIS, ESI-MS and $^1H-NMR$ spectroscopy, and identified as 2'-hydroxydihydrochalcone.

Bactericidal Activity of Grapefruit (Citrus paradisl) Seed Extract-Based Disinfectant

  • Han, Jae-Hong;Kim, Yong-Ung;Kim, Ki-Yeon;Hahm, Young-Tae
    • Journal of Applied Biological Chemistry
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    • v.49 no.3
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    • pp.90-94
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    • 2006
  • Bactericidal activity of grapefruit seed extract (GSE)-based disinfectant, as a safe disinfectant, was measured against five bacteria by Korean Food & Drug Administration (KFDA) dilution-neutralization method. GSE-based disinfectant showed a 99.9999% bactericidal activity against Escherichia coli ATCC 10536, Salmonella typhi ATCC 29629, Staphylococcus aureus ATCC 6538, Bacillus cereus ATCC 11778, and Listeria monocytogenes ATCC 1911 at the concentration of 2.15% GSE. It showed better bactericidal activity against Gram-negative bacteria of E. coli ATCC 10536 and S. typhi ATCC 29629 at lower concentration of GSE (0.43%). Based on the results, it was suggested that a possible bactericidal mechanism of GSE active ingredients was due to the abrupt osmotic shift during the bactericidal activity test by KFDA method.

FT-IR and XRD Analyses of Commercial Methionine-Mineral Chelates

  • Han, Jae-Hong;Chi, Yong-Seok;Shin, Bok-Kyu;Kim, Sang-Kyu;Paik, In-Kee
    • Journal of Applied Biological Chemistry
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    • v.49 no.1
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    • pp.8-10
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    • 2006
  • Compositions of methionine-metal chelates have been investigated by FT-IR and XRD studies to elucidate their molecular structures. It was concluded that Copamin and Zincamin contain a high percentage of crystalline products, presumably 2:1 Methionine-Cu or Zn complexes. On the contrary, FT-IR and XRD spectra of Ferramin didn't show any characteristics of the chelate and it was concluded to contain major components of starting $FeSO_4$ and methionine without chelation.

Reaction Mechanism of Vanadium Haloperoxidase and Marine Natural Products (Vanadium Haloperoxidase의 구조와 작용 메커니즘과 해양천연물질)

  • Han, Jae-Hong
    • Korean Journal of Crystallography
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    • v.16 no.2
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    • pp.66-74
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    • 2005
  • Marine natural products with various bioactivities are featured with similar structure to the common secondary metabolites and generally modified by halogenides, such as chloride, bromide, and iodide ions. Vanadium haloperoxidase is a key enzyme for the production of marine natural products and a metalloenzyme which requires a cofactor of vanadate. This review will cover isolation of vanadium haloperoxidase and the protein structures, as well as reaction mechanism of the metalloenzyme. Finally, reactivity of vanadium haloperoxidase and the biosynthesis of the secondary metabolites of indole, terpenoids, and acetogenins will be described.

Synthesis and the Absolute Configurations of Isoflavanone Enantiomers

  • Won, Dong-Ho;Shin, Bok-Kyu;Han, Jae-Hong
    • Journal of Applied Biological Chemistry
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    • v.51 no.1
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    • pp.17-19
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    • 2008
  • Isoflavanone has been synthesized from the reduction of isoflavone in nearly quantitative yield. Isoflavone with seven equivalents of ammonium formate in the presence of Pd/C in ethanol under $N_2$ atmosphere exclusively produced the two-electron reduced product in two hours. It was characterized by various spectroscopic methods, including UV-VIS, EI-MS, $^1H$-NMR, $^{13}C$-NMR and $^1H$, $^1H$-COSY. The racemic mixture was separated by Sumi-Chiral column chromatography and the absolute configurations of the enantiomers were characterized by circular dichroism spectroscopy.

Structure of Mixed-Anions Tris(2-pyridylmethyl)amine Mn Complex, TPAMnη2-NO3)(η-CIO4)

  • Shin, Bok-Kyu;Kim, Mi-Hyang;Han, Jae-Hong
    • Bulletin of the Korean Chemical Society
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    • v.28 no.3
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    • pp.417-420
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    • 2007
  • Mononuclear mixed-anions Mn complex of TPAMn(η2-NO3)(η-ClO4), where TPA is tris(2-pyridylmethyl)-amine, has been synthesized and characterized. The neutral TPAMn(η2-NO3)(η-ClO4) was obtained from the reaction between Mn(NO3)2·4H2O and [H3TPA](ClO4)3 in MeOH. X-ray crystallographic structure of mononuclear TPAMn(η2-NO3)(η-ClO4) complex showed a seven-coordinated geometry with a tripodal tetradentate TPA, a terminal perchlorate and an η2-bound nitrate.