Enzyme electrodes with substrate and co-enzyme amplification

Abstract

The enzyme couples horseradish peroxidase/glucose dehydrogenase, glucose oxidase/glucose dehydrogenase, and cytochrome b₂/lactate dehydrogenase are applied in enzyme electrodes. Based on amplification by the recyclization reactions catalyzed by these two-enzyme systems, NADH, NAD⁺, glucose, lactate and pyruvate, are determined with 8–40-fold increased sensitivity compared to the unamplified reactions. Detection limits are 1.0 × 10⁻⁶ M NADH, 1.2 × 10⁻⁶ M NAD⁺, 8 × 10⁻⁷ M glucose, and 3 × 10⁻⁷ M lactate or pyruvate.