Spectroelectrochemical investigation of direct electron transfer between resting horseradish peroxidase and its oxidation states promoted by DNA

Direct electron transfer between resting horseradish peroxidase (HRP) and i ts oxidation states was observed at a gold mesh electrode in a spectroelect rochemical cell in the presence of DNA. The conversion between HRP and the oxidized species induced electrochemically was found to be reversible and p arallel to that initiated chemically. DNA played an important role as elect ron carrier and promoted the electron transfer between HRP and the electrod es. Voltammetric results and CD spectra indicated an interaction between HR P and DNA. Moreover, the secondary structure of HRP was slightly disturbed upon mixing with DNA. The direct spectroelectrochemistry of HRP at a gold m esh electrode presented new information on its bioelectrochemical character istics.