F. Millett et al., ELECTRON-TRANSFER BETWEEN CYTOCHROME-C AND CYTOCHROME-C PEROXIDASE, Journal of bioenergetics and biomembranes, 27(3), 1995, pp. 341-351
The reaction between cytochrome c (CC) and cytochrome c peroxidase (Cc
P) is a very attractive system for investigating the fundamental mecha
nism of biological electron transfer. The resting ferric state of CcP
is oxidized by hydrogen peroxide to compound I (CMPI) containing an ox
yferryl heme and an indolyl radical cation on Trp-191. CMPI is sequent
ially reduced to CMPII and then to the resting state CcP by two molecu
les of CC. In this review we discuss the use of a new ruthenium photor
eduction technique and other rapid kinetic techniques to address the f
ollowing important questions: (1) What is the initial electron accepto
r in CMPI? (2) What are the true rates of electron transfer from CC to
the radical cation and to the oxyferryl heme? (3) What are the bindin
g domains and pathways for electron transfer from CC to the radical ca
tion and the oxyferryl heme? (4) What is the mechanism for the complet
e reaction under physiological conditions?