A bienzyme electrochemical biosensor for the detection of collagen l-hydroxyproline

Abstract

l-hydroxyproline (l-Hyp: trans-4-hydroxy-l-proline) is commonly found at high concentrations in connective tissue proteins such as collagen. It is a remarkably useful molecular marker because variation in the level of l-Hyp is associated with various diseases. Recently, the novel enzymes l-hydroxyproline epimerase and d-hydroxyproline dehydrogenase were isolated from bacteria. In this study, a novel electrochemical biosensor for l-Hyp was constructed using these two enzymes. l-hydroxyproline epimerase epimerized l-Hyp to d-hydroxyproline (d-Hyp: cis-4-hydroxy-d-proline), and d-Hyp was oxidized with the reaction catalyzed by d-hydroxyproline dehydrogenase and mediated by ferrocene. We found that the sensor could determine l-Hyp concentrations of 10–100 μM with high-selectivity.

Keywords

• Biosensor
• Electrochemistry
• l-hydroxyproline
• l-hydroxyproline epimerase
• d-hydroxyproline dehydrogenase