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

• Published in: Electroanalysis (New York, N.Y.) Vol. 17; no. 5-6; pp. 445 - 451
• Main Authors: de-los-Santos-Álvarez, Noemí, Lobo-Castañón, María Jesús, Miranda-Ordieres, Arturo J., Tuñón-Blanco, Paulino
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.03.2005; WILEY‐VCH Verlag
• Subjects: Coenzyme A; Electrocatalysis; FAD; Modified graphite electrodes; NADH
• ISSN: 1040-0397; 1521-4109
• DOI: 10.1002/elan.200403180

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 (1×10−8–2.43×10−5 M) with a detection limit of 3 nM.