A specific effect of copper on methylene blue sensitized photodegradation of nucleic acid derivatives.
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Date
1980-12
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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 t½ 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 t½ values was found with
xanthosine–7min 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.
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Keywords
Photodynamic inactivalion, metal effects, methylene blue, purine photobreakdown
Citation
Mohan P Maruthi, Nirmala J, Sastry K Sivarama. A specific effect of copper on methylene blue sensitized photodegradation of nucleic acid derivatives. Journal of Biosciences. 1980 Dec; 2(4): 283-290.