N-Methyl Nucleosidase from Tea Leaves(Biological Chemistry)

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著者

    • NEGISHI Osamu
    • Institute of Applied Biochemistry, University of Tsukuba:(Present office)Tokyo Research Laboratory, Takasago International Corporation
    • OZAWA Tetsuo
    • Institute of Applied Biochemistry, University of Tsukuba

抄録

N-Methyl nucleoside hydrolase (N-methyl nucleosidase, N-MeNase), which hydrolyzes 7-methylxanthosine to produce 7-methylxanthine, was detected in tea-leaf extracts and separated from adenosine nucleosidase (ANase, EC 3.2.2.7) by DEAE-cellulose column chromatography. The optimum pH for the N-MeNase ranged from 8.0 to 8.5. The enzyme was strongly inhibited by EDTA. Inhibition by the hydrolysis products of 7-methylxanthosine and 7-methylinosine was also observed. The molecular weight was estimated to be about 55,000 by gel-filtration. Among purine and N-methylpurine nucleosides, 3- and 7-methylpurine nucleosides were hydrolyzed preferentially by N-MeNase. On the other hand, ANase could not hydrolyze 7-methylxanthosine, although the enzyme showed high activity toward 7-methyladenosine. As a result, it is suggested that N-MeNase catalyzes the hydrolysis reaction of 7-methylxanthosine in the pathway of caffeine biosynthesis, whereas ANase is not directly concerned with it.

収録刊行物

  • Agricultural and biological chemistry

    Agricultural and biological chemistry 52(1), 169-175, 1988-01-23

    社団法人日本農芸化学会

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各種コード

  • NII論文ID(NAID)
    110006323439
  • NII書誌ID(NCID)
    AA00515312
  • 本文言語コード
    ENG
  • 資料種別
    雑誌論文
  • ISSN
    00021369
  • データ提供元
    CJP引用  NII-ELS  J-STAGE 
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