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Regulation of the H + /e − stoichiometry of cytochrome c oxidase from bovine heart by intramitochondrial ATP/ADP ratios
Author(s) -
Frank Viola,
Kadenbach Bernhard
Publication year - 1996
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(96)00096-8
Subject(s) - cytochrome c oxidase , stoichiometry , electron transport complex iv , enzyme , oxidase test , chemistry , heme a , mitochondrion , biochemistry , microbiology and biotechnology , biology , organic chemistry
This paper describes the effect of intramitochondrial ATP/ADP ratios on the H + /e − stoichiometry of reconstituted cytochrome c oxidase (COX) from bovine heart. At 100% intraliposomal ATP the H + /e − stoichiometry of the reconstituted enzyme is decreased to half of the value measured below 98% intraliposomal ATP (above 2% ADP), while it remains constant up to 100% ADP. The decrease is obtained with different COX preparations, independent of the absolute value of the H + /e − stoichiometry. Decrease of H + /e − stoichiometry is prevented by preincubation of the enzyme with a tissue‐specific monoclonal antibody to subunit VIa‐H (heart‐type). Tissue‐specific regulation of the efficiency of energy transduction in COX of muscle mitochondria could have a physilogical function in maintaining the body temperature at rest or sleep, i.e. at low ATP expenditure.