Studies on electrocatalytical kinetic behavior of horseradish peroxidase and assay for hydrogen peroxide at salt bridge supported bilayer lipid membrane

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 b etween HRP and LA anion sites in the sb-BLM, which results in the enhanceme nt of the electron exchange between the protein and the electrode surface. A quasireversible electron transfer was observed even in the absence of med iators. A novel and biological compatible biosensor was constructed. The el ectrocatalytically kinetic behavior of HRP was investigated with this biose nsor. Furthermore, the cathodic peak current (I-pc) of HRP was increased in the presence of hydrogen peroxide, the intensity of which is strictly depe ndent on the concentration of hydrogen peroxide. The relationship is DeltaI (pc)(A)=[1.215 InCH2O2(mmol L-1)+ 1.018]x 10(-7). The effects of the coexis ting substances and the pH values on the response of the biosensor were als o investigated for optimum analytical performance.