Hydrogen Evolution Facilitates Reduction of DNA Guanine Residues at the Hanging Mercury Drop Electrode: Evidence for a Chemical Mechanism
Hydrogen Evolution Facilitates Reduction of DNA Guanine Residues at the Hanging Mercury Drop Electrode: Evidence for a Chemical Mechanism
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析氢促进悬挂汞滴电极处 DNA 鸟嘌呤残基的还原：化学机制的证据
DOI：
10.1002/elan.201600242
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发表时间：
2016
期刊：
影响因子：
3
通讯作者：
M. Fojta
中科院分区：
文献类型：
--
作者：
A. Daňhel;L. Havran;L. Trnková;M. Fojta
鸟嘌呤(G)，以及核苷，核苷酸中的G残基
Guanine (G), as well as G residues in nucleosides, nucleotides
and nucleic acids, undergo chemically reversible (but
electrochemically irreversible) reduction/oxidation processes
at the mercury-based electrodes. It has been established that G
is reduced to 7,8-dihydroguanine at highly negative potentials.
The reduction product is oxidized back to G around -0.25V,
giving rise to anodic peak G. Previous studies suggested
involvement of a chemical mechanism involving electrochemically
generated hydrogen radicals in the G reduction process. In this
work we studied effects of cisplatin and pH on the G reduction
process. We have found that catalytic hydrogen evolution
accompanying electrochemical reduction of cisplatin markedly
facilitates reduction of G. Minimum negative potential required
for G reduction were shifted to less negative values and
correlated with the onset of catalytic currents of cisplatin.
Analogous shifts of the potential of G reduction were observed
upon lowering pH of the background electrolyte (i.e.,
increasing the availability of protons to generate hydrogen
radicals). Ammonium ions markedly increased efficiency of G
reduction, which may be explained by generation of active
hydrogen via formation and subsequent decomposition of ammonium
amalgam. Our results strongly suggest that chemical
mechanism(s) involving hydrogen radicals, electrochemically
and/or electrocatalytically generated at the HMDE, contribute
to the guanine 7,8-dihydroguanine conversion.