Self-assembled monolayers suitable for electron-transfer promotion of copper, zinc-superoxide dismutase

A large variety of thiols and disulfides were studied with respect to their capability to promote the direct electrochemistry of bovine erythrocyte copper, zinc-superoxide dismutase (Cu, Zn-SOD). Experimental results strongly suggested that the electron-transfer (ET) properties of Cu, Zn-SOD remarkably depend on the structure of the promoters used, revealing the essence of structure-associated promoted ET properties of SOD. Among all the thiols and disulfides tested, the COOH-terminated aliphatic thiols and disulfides with a short alkylene chain [-(CH2)-(n), (n = 1-3)] were found to be favorable for the ET of SOD. The promoted electrochemical process and the probable explanation for the different capability of the various thiols and disulfides for promoting the ET of SOD were presented and discussed. (C) 2004 Elsevier B.V. All rights reserved.