cytochrome-c-t and ethylene-dichloride

The electron transfer (ET) between cytochrome c (Cyt c) in water (W) and 1,1'-dimethylferrocene (DiMFc) in 1,2-dichloroethane (DCE) was studied. The cyclic voltammograms obtained for the interfacial ET under various conditions could be well reproduced by digital simulation based on the ion-transfer (IT) mechanism, in which the ET process occurs not at the DCE/W interface but in the W phase nearest the interface. In this mechanism, the current signal is due to the IT of DiMFc(+) as the reaction product. On the other hand, the measurement of the double-layer capacity showed that Cyt c is adsorbed at the DCE/W interface. However, the contribution from the adsorbed proteins to the overall ET is considered to be small because of the thicker reaction layer in the IT mechanism. These findings would offer a useful suggestion for the behaviors of Cyt c in vivo.

Topics: Cytochromes c; Electrochemical Techniques; Electron Transport; Ethylene Dichlorides; Models, Molecular; Oils; Water

The transfer of proteins by the anionic surfactant bis(2-ethylhexyl) sulfosuccinate (AOT) at a polarized 1,2-dichloroethane/water (DCE/W) interface was investigated by means of ion-transfer voltammetry. When the tetrapentylammonium salt of AOT was added to the DCE phase, the facilitated transfer of certain proteins, including cytochrome c (Cyt c), ribonuclease A, and protamine, could be controlled electrochemically, and a well-defined anodic wave for the transfer was obtained. At low pH values (e.g., pH 3.4), the anodic wave was usually well-separated from the wave for the formation of protein-free (i.e., unfilled) reverse micelles. The anodic wave for the protein transfer was analyzed by applying the theory for facilitated transfer of ions by charged ligands and then supplying information regarding the number of AOT anions reacting with one protein molecule and the total charge carried by the protein transfer. However, controlled-potential electrolyses performed for the transfer of Cyt c, which is red, revealed that the protein-AOT complexes were unstable in DCE and liable to aggregate at the interface when the pH of the W phase was 3.4. At pH 7.0, when formation of unfilled reverse micelles occurred simultaneously, the protein-AOT complexes appeared to be stabilized, probably via fusion with unfilled reverse micelles.

Topics: Animals; Cytochromes c; Electrochemistry; Electrolysis; Ethylene Dichlorides; Hydrogen-Ion Concentration; Micelles; Protamines; Proteins; Ribonuclease, Pancreatic; Succinates; Surface-Active Agents; Water