Quenching of nucleotide-derived radicals by bisbenzimidazole derivative Hoechst-33258 in aqueous solution

Mohan, H. ; Adhikary, A. ; Jain, V. ; Mittal, J. P. (2000) Quenching of nucleotide-derived radicals by bisbenzimidazole derivative Hoechst-33258 in aqueous solution Proceedings of the Indian Academy of Sciences - Chemical Sciences, 112 (4). pp. 487-496. ISSN 0253-4134

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Official URL: http://ns1.ias.ac.in/chemsci/Pdf-Aug2K/Pc2912.pdf

Related URL: http://dx.doi.org/10.1007/BF02704354

Abstract

The pulse radiolysis technique has been employed to investigate the reaction of DNA-minor-groove ligand bisbenzimidazole Hoechst 33258 with pyrimidine and purine nucleotide-derived radicals. Formation of an N-centred Hoechst-33258 radical is observed. Bimolecular rate constants and the yields of Hoechst-33258 radical have been evaluated. While the rate constant for the reaction of pyrimidine-derived radicals with Hoechst-33258 remained the same (1-2) × 109 dm3 mol-1 s-1, the yields of the Hoechst-33258 radical varied from 25% (5'-cytidine monophosphate) to 75% (5'-guanosine monophosphate) under anoxic conditions. The rate constant values for the reaction of purine-derived radicals with Hoechst-33258, under oxic and anoxic conditions, remained the same whereas with pyrimidine-derived radicals, the rate constant value under oxic conditions was about two orders of magnitude lower than under anoxic conditions. The difference in the yields of Hoechst-33258 radical with various nucleotide-derived radicals suggest the formation of different types of radicals and that the reaction mainly occurs by electron transfer from Hoechst-33258 to the nucleotide radicals.

Item Type:Article
Source:Copyright of this article belongs to Indian Academy of Sciences.
Keywords:Nucleotide-derived Radicals; Hoechst-33258; Pulse Radiolysis
ID Code:25742
Deposited On:04 Dec 2010 11:47
Last Modified:17 May 2016 09:10

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