Characterization of Coumarin-Specific Prenyltransferase Activities in Citrus limon Peel

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Author(s)

    • SASAKI Kanako
    • Laboratory of Plant Gene Expression, Research Institute for Sustainable Humanosphere, Kyoto University
    • TSURUMARU Yusuke
    • Laboratory of Plant Gene Expression, Research Institute for Sustainable Humanosphere, Kyoto University
    • SUGIYAMA Akifumi
    • Laboratory of Plant Gene Expression, Research Institute for Sustainable Humanosphere, Kyoto University
    • UTO Yoshihiro
    • Department of Life System, Institute of Technology and Science, Graduate School, The University Tokushima
    • HORI Hitoshi
    • Department of Life System, Institute of Technology and Science, Graduate School, The University Tokushima
    • AZUMA Jun-ichi
    • Division of Environmental Science and Technology, Graduate School of Agriculture, Kyoto University
    • YAZAKI Kazufumi
    • Laboratory of Plant Gene Expression, Research Institute for Sustainable Humanosphere, Kyoto University

Abstract

Coumarins, a large group of polyphenols, play important roles in the defense mechanisms of plants, and they also exhibit various biological activities beneficial to human health, often enhanced by prenylation. Despite the high abundance of prenylated coumarins in citrus fruits, there has been no report on coumarin-specific prenyltransferase activity in citrus. In this study, we detected both O- and C-prenyltransferase activities of coumarin substrates in a microsome fraction prepared from lemon (Citrus limon) peel, where large amounts of prenylated coumarins accumulate. Bergaptol was the most preferred substrate out of various coumarin derivatives tested, and geranyl diphosphate (GPP) was accepted exclusively as prenyl donor substrate. Further enzymatic characterization of bergaptol 5-O-geranyltransferase activity revealed its unique properties: apparent Km values for GPP (9 µM) and bergaptol (140 µM) and a broad divalent cation requirement. These findings provide information towards the discovery of a yet unidentified coumarin-specific prenyltransferase gene.

Coumarins, a large group of polyphenols, play important roles in the defense mechanisms of plants, and they also exhibit various biological activities beneficial to human health, often enhanced by prenylation. Despite the high abundance of prenylated coumarins in citrus fruits, there has been no report on coumarin-specific prenyltransferase activity in citrus. In this study, we detected both <i>O</i>- and <i>C</i>-prenyltransferase activities of coumarin substrates in a microsome fraction prepared from lemon (<i>Citrus limon</i>) peel, where large amounts of prenylated coumarins accumulate. Bergaptol was the most preferred substrate out of various coumarin derivatives tested, and geranyl diphosphate (GPP) was accepted exclusively as prenyl donor substrate. Further enzymatic characterization of bergaptol 5-<i>O</i>-geranyltransferase activity revealed its unique properties: apparent <i>K</i><sub>m</sub> values for GPP (9 µ<small>M</small>) and bergaptol (140 µ<small>M</small>) and a broad divalent cation requirement. These findings provide information towards the discovery of a yet unidentified coumarin-specific prenyltransferase gene.

Journal

  • Bioscience, Biotechnology, and Biochemistry

    Bioscience, Biotechnology, and Biochemistry 76(7), 1389-1393, 2012-07-23

    Japan Society for Bioscience, Biotechnology, and Agrochemistry

References:  31

Codes

  • NII Article ID (NAID)
    10030982292
  • NII NACSIS-CAT ID (NCID)
    AA10824164
  • Text Lang
    ENG
  • Article Type
    ART
  • ISSN
    09168451
  • NDL Article ID
    023841140
  • NDL Call No.
    Z53-G223
  • Data Source
    CJP  NDL  IR  J-STAGE 
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