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      Permanent link:
      https://www.ias.ac.in/article/fulltext/jbsc/002/04/0283-0290

    • Keywords

       

      Photodynamic inactivalion; metal effects; methylene blue; purine photobreakdown

    • Abstract

       

      Among several metal ions tested, Cu2+ was unique in slowing down methylene blue sensitized photodynamic breakdown of some nucleic acid bases and nucleosides. The t1/2 values were increased in the case of xanthine and uric acid by Cu2+, but without any alteration in the nature or amounts of photoproducts formed. Xanthine was degraded quantitatively to allantoin and urea.

      The breakdown of the sugar moiety of nucleosides was more drastically retarded than that of the purine ring. The decomposition rate and its magnitude was dependent on the concentration of Cu2+ as well as the nucleoside. The most profound increase in t1/2 values was found with xanthosine—7 min for the purine ring and 65 min for the ribose moiety, at 0.6 mM Cu2+ Hg2+ in the case of xanthine, and some paramagnetic metal ions in the case of the nucleosides, slowed down the photobreakdown to a small extent; however, differential effects were not observed unlike with Cu2+. None of the other metal ions tested significantly influenced the process.

    • Author Affiliations

       

      P Maruthi Mohan1 J Nirmala1 K Sivarama Sastry1

      1. Department of Biochemistry, Osmaniu University, Hyderabad - 500 007
    • Dates

       
  • Journal of Biosciences | News

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