J. Biol. Chem., Vol. 263, Issue 15, 7159-7163, 05, 1988
Does the peroxide compound of cytochrome oxidase contain a ferryl iron?
C Kumar, A Naqui, L Powers, YC Ching and B Chance
Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia 19104.
The reaction of peroxide with cytochrome oxidase generates a peroxide
compound having a Soret maximum at 428 nm. X-ray absorption spectroscopy
analysis of the local structure of the active site iron shows marked
similarity to that of the cytochrome c peroxidase intermediate Compound ES,
which contains a short iron to proximal nitrogen distance compared to
globins. Reductive titration of the 580 nm band of this compound indicates
that the iron is one oxidizing equivalent above the resting oxidized form.
These results support the presence of a ferryl iron (Fe(IV) = O) in the
peroxide compound similar to that found for the peroxidases.