Studies on Electrocatalytical Kinetic Behavior of Horseradish Peroxidase and Assay for Hydrogen Peroxide at Salt Bridge Supported Bilayer Lipid Membrane

Abstract

This article reports on the electrochemical behavior, relative to the Fe(III)-Fe(II) conversion, of horseradish peroxidase (HRP) incorporated in a salt bridge-supported bilayer lipid membrane (sb-BLM) modified with lauric acid (LA). The incorporation of HRP was achieved by electrostatic interaction between HRP and LA anion sites in the sb-BLM, which results in the enhancement of the electron exchange between the protein and the electrode surface. A quasireversible electron transfer was observed even in the absence of mediators. A novel and biological compatible biosensor was constructed. The electrocatalytically kinetic behavior of HRP was investigated with this biosensor. Furthermore, the cathodic peak current (IPc) of HRP was increased in the presence of hydrogen peroxide, the intensity of which is strictly dependent on the concentration of hydrogen peroxide. The relationship is ΔIPc(A)=[1.215 lnC(mmol L−1)+1.018]×10−7. The effects of the coexisting substances and the pH values on the response of the biosensor were also investigated for optimum analytical performance.