Studying of Electron Transfer Kinetics of Azurin Immobilized on New Phenolic Terminated Self Assembled Monolayer by Scanning Electrochemical Microscopy

The electrochemical behavior of Azurin immobilized onto a 2-(2- mercaptophenylnitrilomethylidyne) phenol (MPNM) self-assembled monolayer (SAM) on a gold electrode is investigated using scanning electrochemical microscopy (SECM). The tunneling electron transfer (ET) rate constant between the immobilized protein and the underlying electrode surface, and also the bimolecular ET rate constant between the immobilized protein and a probe has been obtained using approach curves. The approach curves were recorded at different substrate overpotentials in the presence of various concentrations of ferrocyanide as a probe and various surface concentrations of Azurin; then the standard tunneling ET and bimolecular rate constants are obtained as 2.3 ± 0.3 × 103 s−1 and 2.0 ± 0.5 × 108 cm3 mol−1 s−1, respectively.