Dependence of the redox reaction of cytochrome c on the mixing state of binary self-assembled monolayers composed of 11-aminoundecanethiol and 10-mercaptoundecanoic acid on Au(1Â 1Â 1)

Electron transfer (ET) of horse heart cytochrome c (cyt c) immobilized on the artificially phase-separated binary self-assembled monolayers (SAMs) composed of 11-amino-1-undecanthiolate (AUTe) and 10-carboxy-1-decanethiolate (MUAe), (p-SAMs) has been investigated. It has been found that cyt c selectively adsorbs on domains of MUAe of the p-SAMs by the electrostatic attraction and the ET of cyt c on p-SAMs is enhanced compared to that of cyt c adsorbed on the homogeneously mixed SAM of AUTe and MUAe and also on the single-component MUA SAM. This suggests a favorable orientation of cyt c on p-SAMs for ET with the electrode.