Open AccessPhotoinduced intracomplex electron transfer between cytochrome c oxidase and TUPS‐modified cytochrome c
Author(s) -
Kotlyar Alexander,
Borovok Natalia,
Hazani Miron,
Szundi Istvan,
Einarsdóttir Ólöf
Publication year - 2000
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1327.2000.01655.x
Subject(s) - cytochrome c peroxidase , cytochrome c oxidase , cytochrome c , cytochrome , coenzyme q – cytochrome c reductase , cytochrome c1 , chemistry , cytochrome p450 reductase , cytochrome b6f complex , photochemistry , cytochrome b , biochemistry , enzyme , mitochondrion , mitochondrial dna , gene
A novel method for initiating intramolecular electron transfer in cytochrome c oxidase is reported. The method is based upon photoreduction of cytochrome c labeled with thiouredopyrene‐3,6,8‐trisulfonate in complex with cytochrome oxidase. The thiouredopyrene‐3,6,8‐trisulfonate‐labeled cytochrome c was prepared by incubating the thiol reactive form of the dye with yeast iso‐1‐cytochrome c , containing a single cysteine residue. Laser pulse excitation of a stoichiometrical complex between thiouredopyrene‐3,6,8‐trisulfonate‐cytochrome c and bovine heart cytochrome oxidase at low ionic strength resulted in the reduction of cytochrome c by the excited form of thiouredopyrene‐3,6,8‐trisulfonate and subsequent intramolecular electron transfer from the reduced cytochrome c to cytochrome oxidase. The maximum efficiency by a single laser pulse resulted in the reduction of ≈ 17% of cytochrome a , and was achieved only at a 1 : 1 ratio of cytochrome c to cytochrome oxidase. At higher cytochrome c to cytochrome oxidase ratios the heme a reduction was strongly suppressed.