Open AccessElectron‐Transfer Reactions between Redox Proteins from a Bacterium ( Pseudomonas fluorescens ) and Mammalian‐Heart Muscle
Author(s) -
Greenwood Colin,
Finazzi Agrò Alessandro,
Guerrieri Pietro,
Avigliano Luciana,
MondovÍ Bruno,
Antonini Eraldo
Publication year - 1971
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1971.tb01624.x
Subject(s) - azurin , cytochrome , cytochrome c oxidase , redox , cytochrome c , electron transfer , chemistry , electron transport chain , electron transport complex iv , electron exchange , photochemistry , biochemistry , inorganic chemistry , enzyme , mitochondrion , ion , organic chemistry
1 Electron‐exchange rates from the reduced bacteril redox proteins, cytochrome c 551 and azurin to horse‐heart ferricytochrome c have been measured. Values of 8 × 10 4 M −1 sec −1 and and 1.1 × 10 3 M −1 sec −1 for the cytochrome–cytochrome exchange and azurin–cytochrome exchange have been found with activation energies of 51 and 58.5 kJ (12.3 and 14 kcal), respectively. 2 A method is described whereby electron‐exchange rates can be measured between specifically different cytochromes which are nevertheless almost identical in their spectral characteristic and where, consequently, the direct determination would be difficult. 3 Some observations on the oxidation of horse‐heart ferrocytochrome c by mammalian cytochrome oxidase are presented which suggest this to be a complicated mechanism markedly influenced by ionic strength and cytochrome c concentration.