Electrical Communication between Electrodes and NAD(P)+-Dependent Enzymes Using Pyrroloquinolinequinone-Enzyme Electrodes in a Self-Assembled Monolayer Configuration: Design of a New Class of Amperometric Biosensors

Itamar Willner*, Azalia Riklin

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

200 Scopus citations

Abstract

The development of an amperometric sensor utilizing the NAD(P)+-cofactor-dependent enzyme, malic enzyme, is described using a quinone-enzyme monolayer-modified electrode. Pyrroloquinolinequinone (PQQ, 1) was covalently linked to a self-assembled monolayer of cysteamine on an Au electrode. The resulting PQQ-monolayer electrode (PQQ surface coverage 1.98 × 10−10 mol·cm⅂2) catalyzes the electrooxidation of NADPH and NADH. The developed anodic currents are controlled by NAD(P)H concentrations and provide an amperometric sensor for the cofactor. Malic enzyme has been covalently linked to the PQQ-monolayer electrode. The resulting PQQ-enzyme electrode (enzyme coverage 4.01 × 10−12 mol·cm−2) provides an amperometric biosensor for the determination of malic acid in the presence of the cofactor NADP+. In this system, biocatalyzed oxidation of malic acid generates NADPH that is oxidized by the PQQ component.

Original languageEnglish
Pages (from-to)1535-1539
Number of pages5
JournalAnalytical Chemistry
Volume66
Issue number9
DOIs
StatePublished - 1 May 1994

Fingerprint

Dive into the research topics of 'Electrical Communication between Electrodes and NAD(P)+-Dependent Enzymes Using Pyrroloquinolinequinone-Enzyme Electrodes in a Self-Assembled Monolayer Configuration: Design of a New Class of Amperometric Biosensors'. Together they form a unique fingerprint.

Cite this