The “Ferrous-Oxy” Intermediate in the Reaction of Dioxygen with Fully Reduced Cytochromesaa3andbo3
- 1 January 1996
- journal article
- research article
- Published by American Chemical Society (ACS) in Biochemistry
- Vol. 35 (50) , 16241-16246
- https://doi.org/10.1021/bi961433a
Abstract
We have studied the reactions with oxygen of two terminal oxidases, cytochrome c oxidase from mitochondria and cytochrome bo3 from Escherichia coli. In each case, flow-flash methodology was used to react the fully reduced enzyme with a high concentration of oxygen (1 mM), and absorbance changes were recorded for a number of separate wavelengths in the α-band (visible) region. In both enzymes, an early kinetic phase could be resolved, corresponding to the binding of oxygen to produce a ferrous-oxy heme intermediate. In cytochrome c oxidase, this intermediate appears with a time constant of 10 μs; its spectrum has a peak at 595 nm (relative to the unliganded reduced enzyme). In cytochrome bo3, the ferrous-oxy intermediate, resolved by optical absorbance spectroscopy for the first time, appears with a time constant of 11 μs and has a broad maximum near 570 nm.Keywords
This publication has 11 references indexed in Scilit:
- Photolytic activity of early intermediates in dioxygen activation and reduction by cytochrome oxidaseJournal of the American Chemical Society, 1995
- Facilitated intramolecular electron transfer in cytochrome bo‐type ubiquinol oxidase initiated upon reaction of the fully reduced enzyme with dioxygenFEBS Letters, 1994
- Observation of the Fe–O2 and FeIV=O stretching Raman bands for dioxygen reduction intermediates of cytochrome bo isolated from Escherichia coliFEBS Letters, 1994
- Coordination dynamics of heme-copper oxidases. The ligand shuttle and the control and coupling of electron transfer and proton translocationJournal of Bioenergetics and Biomembranes, 1993
- Discrete steps in dioxygen activation?The cytochrome oxidase/O2 reactionJournal of Bioenergetics and Biomembranes, 1993
- Observation of the iron(II)-oxygen stretching Raman band for cytochrome oxidase compound A at ambient temperatureJournal of the American Chemical Society, 1990
- Time-resolved Raman detection of .nu.(Fe-O) in an early intermediate in the reduction of oxygen by cytochrome oxidaseJournal of the American Chemical Society, 1989
- Formation and decay of the primary oxygen compound of cytochrome oxidase at room temperature as observed by stopped flow, laser flash photolysis and rapid scanning.Journal of Biological Chemistry, 1984
- Functional intermediates in the reaction of membrane-bound cytochrome oxidase with oxygen.Journal of Biological Chemistry, 1975
- Reactions of cytochrome oxidase with oxygen and carbon monoxideBiochemical Journal, 1963