The redox reactions of cytochrome c (cyt c) adsorbed on self-assembled monolayers (SAMs) of 4-mercaptobenzoic acid (4-MBA) and 4-mercaptohydrocinnamic acid (4-MHCA) are studied using cyclic voltammetry and ER spectroscopy. A monolayer of cyt c in a stable, electroactive state is formed on close-packed monolayers of both aromatic thiols. The redox potentials of cyt c are 35 mV for 4-MBA and 20 mV vs. Ag/AgCl for 4-MHCA. The electron transfer (ET) rate constants, ket, of cyt c at pH 7 are determined from the frequency dependence of the ER response to be 1800 s-1 for 4-MBA system and 3900 s-1 for 4-MHCA. The ket of adsorbed cyt c tends to be larger on the SAMs of both aromatic thiols than on the SAM of 6-mercaptohexanoic acid having a similar thickness, suggesting that the difference in the SAM structure is reflected to the ket of cyt c.
|出版ステータス||Published - 1997 12月 1|
ASJC Scopus subject areas
- 化学 (全般)