Single electron reduction of 'slow' and 'fast' cytochrome-c oxidase.
Evidence is presented that single electron reduction is sufficient for rapid electron transfer (k greater than 20 s-1 at pH 8.0 in 0.43 M potassium EDTA) between haem a/CuA and the binuclear centre in 'fast' oxidase, whereas in 'slow' oxidase intramolecular electron transfer is slow even when both CuA and haem a are reduced (k congruent to 0.01 s-1). However, while a single electron can equilibrate rapidly between CuA, haem a and CuB in 'fast' oxidase, it seems that equilibration with haem a3 is relatively slow (k congruent to 2 s-1). Electron transfer between cytochrome c and CuA/haem a is similar for both types of enzyme (k congruent to 2.4 x 10(5) M-1.s-1).
Moody
A J
AJ
Glynn Research Institute, Bodmin, Cornwall, UK.
Brandt
U
U
Rich
P R
PR
D000818:Animals; D002417:Cattle; D004579:Electron Transport; D003576:Electron Transport Complex IV / Q000737:chemistry* / Q000145:classification; D006736:Horses; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009206:Myocardium / Q000201:enzymology; D010084:Oxidation-Reduction; D011487:Protein Conformation
D003576:Electron Transport Complex IV