Electrochemical and Catalytic Properties of the Adenine Coenzymes FAD and Coenzyme A on Pyrolytic Graphite Electrodes

Abstract

Redox properties of two coenzymes, flavin adenine dinucleotide (FAD) and coenzyme A (CoA) are studied on pyrolytic graphite electrodes. Both of them exhibit an oxidation process at about 1.2 V in pH 9, associated with the oxidation of their adenine moiety. The resulting adsorbed oxidation products have a common structure, an electroactive quinone-imine that acts as efficient catalyst of the oxidation of NADH at low potentials. The influence of the structure on their electrochemical features in comparison with other adenine derivatives is studied. Finally, a modified electrode prepared with the oxidation product of CoA was used to determine NADH in a wide linear range (1 Â 10 À8 -2.43 Â 10 À5 M) with a detection limit of 3 nM.

Electrochemical Biosensor Based on Integrated Assembly of Dehydrogenase Enzymes and Gold Nanoparticles

“…It is worth comparing the present electrode with the other electrodes based on exfoliated graphite, carbon nanotubes, , redox mediators, ,, and redox polymers 37,42 used for the detection of NADH. Recently, Alvarez and co-workers reported the excellent detection limit of 3 nM, with a graphite electrode modified with redox mediator derived from coenzyme A at 0.1 V . However, a rapid loss of the sensitivity due to the leaching of the redox mediator and fouling of the electrode surface 55 was noticed.…”

Electroanalysis of NADH Using Conducting and Redox Active Polymer/Carbon Nanotubes Modified Electrodes-A Review

“…The resulting adsorbed oxidation products have a common structure, an electroactive quinone-imine that acts as efficient catalyst of the oxidation of NADH at low potentials. Finally, a modified electrode prepared with the oxidation product of CoA was used to determine NADH in a wide linear range (1×10 -8 – 2.43×10 -5 M) with a detection limit of 3 nM [118]. …”

Enoxacin—Tb3+Complex as an Environmentally Friendly Fluorescence Probe for Coenzyme A and Its Application

“…CoA has a reactive thiol group that gives it a role as an acyl carrier in a number of metabolic reactions. Because of its relatively high free energy in hydrolysis, the thioester moiety has a high acyl group transfer potential when donating its acyl group to acceptor molecules (Santos-Á lvarez et al 2005;Lehninger, Nelson, and Cox 1993).…”