ELECTROCHEMISTRY OF HORSE HEART CYTOCHROME-C

The electrochemical behavior of horse heart ferricytochrome c at a gold electrode in the presence of 4, 4ʹ-bipyridyl is described. DC and AC cyclic voltammograms are obtained due to the quasi-reversible electrode reaction of cytochrome c, which has E 1/2r = +0.255 V vs. NHE. Combined coulometric and spectrophotometric studies confirm that the one-electron reduction is due to the cytochrome. 1, 2-Bis(4-pyridyl)ethylene is also effective in promoting electron transfer, The results are consistent with adsorption of the heterocycle to form a conducting layer on the gold surface. Variation of the AC cyclic voltammetry with pH indicates the existence of an electroactive and an electroinactive form of cytochrome c at alkaline pH while at acidic pH protonation of 4, 4ʹ-bipyridyl appears to affect the observed electrochemistry. © 1979, American Chemical Society. All rights reserved.