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Electrogenic proton exchange between cytochrome a 3 active center and M‐aqueous phase
Author(s) -
Konstantinov Alexander,
Vygodina Tatiana,
Andreev Igor M.
Publication year - 1986
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(86)80692-5
Subject(s) - proton , center (category theory) , chemistry , phase (matter) , aqueous solution , cytochrome , cytochrome c , physics , crystallography , biochemistry , organic chemistry , nuclear physics , enzyme , mitochondrion
The rate of cyanide binding with the oxidized cytochrome‐ c oxidase in proteoliposomes is controlled by ionization of a protein group with p K ~6.7, the ligand reacting with the protonated enzyme only [(1983) Bioorg. Chem. (USSR) 9,216‐227]. As shown here, the kinetics of cyanide binding depends on the pH inside the proteoliposomes. The reaction rate is affected by the electrical potential difference across the proteoliposome membranes as if the a 3 ‐linked ionizable group exchanged H + with the proteoliposome interior electrogenically. The data corroborate a hypothesis on the existence of a proton well communicating cytochrome oxidase O 2 ‐reducing center with the M‐aqueous phase.