Voltammetric studies of selected porphyrin G-quadruplex ligands and their interaction with DNA in solution and at the mercury electrode surface

The acceleration effect of p-toluidine on the electroreduction of Zn(II) on the mercury electrode surface in binary mixtures water-methanol and water-dimethylformamide is discussed. The obtained apparent and true forward rate constants of Zn(II) reduction indicate that the rate constant of the first electron transfer increases in the presence of p-toluidine. The acceleration effect may probably be accounted for by the concept of the formation on the mercury electrode an activated complex, presumably composed of p-toluidine and solvent molecules.

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Electrochemical study of the mechanism and kinetics of reductive glycoside elimination of adriamycin adsorbed on a mercury electrode surface

Journal of Electroanalytical Chemistry ◽

10.1016/0022-0728(87)80013-x ◽

1987 ◽

Vol 225 (1-2) ◽

pp. 187-204 ◽

Cited By ~ 7

Author(s):

Kenji Kano ◽

Tomonori Konse ◽

Keiko Hasegawa ◽

Bunji Uno ◽

Tanekazu Kubota

Keyword(s):

Electrode Surface ◽

Mercury Electrode ◽

Electrochemical Study ◽

Mechanism And Kinetics ◽

Kinetics Of

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Voltammetry and molecular assembly of G-quadruplex DNAzyme on single-crystal Au(111)-electrode surfaces – hemin as an electrochemical intercalator

Faraday Discussions ◽

10.1039/c6fd00091f ◽

2016 ◽

Vol 193 ◽

pp. 99-112 ◽

Cited By ~ 6

Author(s):

Ling Zhang ◽

Jens Ulstrup ◽

Jingdong Zhang

Keyword(s):

Single Crystal ◽

Single Molecule ◽

Electrode Surface ◽

Molecular Assembly ◽

Electrode Surfaces ◽

Potential Control ◽

G Quadruplex ◽

Tunnelling Microscopy ◽

Dna Quadruplexes

DNA quadruplexes (qs) are a class of “non-canonical” oligonucleotides (OGNs) composed of stacked guanine (G) quartets stabilized by specific cations. Metal porphyrins selectively bind to G-qs complexes to form what is known as DNAzyme, which can exhibit peroxidase and other catalytic activity similar to heme group metalloenzymes. In the present study we investigate the electrochemical properties and the structure of DNAzyme monolayers on single-crystal Au(111)-electrode surfaces using cyclic voltammetry and scanning tunnelling microscopy under electrochemical potential control (in situ STM). The target DNAzyme is formed from a single-strand OGN with 12 guanines and iron(iii) porphyrin IX (hemin), and assembles on Au(111) through a mercapto alkyl linker. The DNAzyme monolayers exhibit a strong pair of redox peaks at 0.0 V (NHE) at pH 7 in acetate buffer, shifted positively by about 50 mV compared to free hemin weakly physisorbed on the Au(111)-electrode surface. The voltammetric hemin signal of DNAzyme is enhanced 15 times compared with that of hemin adsorbed directly on the Au(111)-electrode surface. This is indicative of both the formation of a close to dense DNAzyme monolayer and that hemin is strongly bound to the immobilized 12G-qs in well-defined orientation favorable for interfacial ET with a rate constant of 6.0 ± 0.4 s−1. This is supported by in situ STM which discloses single-molecule G-quartet structures with a size of 1.6 ± 0.2 nm.

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