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    • Decarboxylation of arginine and ornithine by arginine decarboxylase purified from cucumber (Cucumis sativus) seedlings

      G L Prasad P R Adiga

      Volume 10 Issue 2 June 1986 pp 203-213

    • Fulltext

       

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      Permanent link:
      https://www.ias.ac.in/article/fulltext/jbsc/010/02/0203-0213

    • Keywords

       

      Arginine decarboxylase; purification; ornithine decarboxylase; modulation; DFMO; dual activities

    • Abstract

       

      A purified preparation of arginine decarboxylase fromCucumis sativus seedlings displayed ornithine decarboxylase activity as well. The two decarboxylase activities associated with the single protein responded differentially to agmatine, putrescine andPi. While agmatine was inhibitory (50 %) to arginine decarboxylase activity, ornithine decarboxylase activity was stimulated by about 3-fold by the guanido arnine. Agmatine-stimulation of ornithine decarboxylase activity was only observed at higher concentrations of the amine. Inorganic phosphate enhanced arginine decarboxylase activity (2-fold) but ornithine decarboxylase activity was largely uninfluenced. Although both arginine and ornithine decarboxylase activities were inhibited by putrescine, ornithine decarboxylase activity was profoundly curtailed even at 1 mM concentration of the diamine. The enzyme-activated irreversible inhibitor for mammalian ornithine decarboxylase,viz. α-difluoromethyl ornithine, dramatically enhanced arginine decarboxylase activity (3–4 fold), whereas ornithine decarboxylase activity was partially (50%) inhibited by this inhibitor. At substrate level concentrations, the decarboxylation of arginine was not influenced by ornithine andvice-versa. Preliminary evidence for the existence of a specific inhibitor of ornithine decarboxylase activity in the crude extracts of the plant is presented. The above results suggest that these two amino acids could be decarboxylated at two different catalytic sites on a single protein.

    • Author Affiliations

       

      G L Prasad1 P R Adiga1

      1. Department of Biochemistry, Indian Institute of Science, Bangalore - 560012, India

    • Dates

       
      Published
      June 1986
      Manuscript received
      26 December 1985
      Manuscript revised
      15 April 1986

  • Journal of Biosciences | News

      Forthcoming Special issue.


    • To trigger further research on plant mitochondria, the Journal of Biosciences is bringing out a special issue titled "Plant Mitochondria: Properties and Interactions with Other Organelles".


      Plant mitochondria are quite distinct and have unique features, such as a cyanide-insensitive alternate pathway. They also interact with chloroplasts to optimize photosynthetic carbon assimilation.


      Submissions are welcome until 30 July 2023. The contributions can be original articles, short communications, reviews, or mini-reviews on any topic related to plant mitochondria.


      Authors can submit their articles online at https://www.editorialmanager.com/jbsc/default2.aspx

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