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Cytochrome oxidase‐catalyzed superoxide generation from hydrogen peroxide
Author(s) -
Ksenzenko M.Yu.,
Vygodina T.V.,
Berka V.,
Ruuge E.K.,
Konstantinov A.A.
Publication year - 1992
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(92)80328-e
Subject(s) - chemistry , cytochrome c oxidase , hydrogen peroxide , superoxide , catalase , radical , superoxide dismutase , oxidase test , photochemistry , oxygen , cyanide , cytochrome c , cytochrome c peroxidase , electron transport complex iv , enzyme , biochemistry , inorganic chemistry , organic chemistry , mitochondrion
Superoxide dismutase is shown to affect spectral changes observed upon cytochroma c oxidase reaction with H 2 O 2 , which indicates a possibility of O − 2 radicals being formed in the reaction. Using DMPO as a spin trap, generation of superoxide radicals from H 2 O 2 in the presence of cytochrome oxidase is directly demonstrated. The process is inhibited by cyanide and is not observed with a licat‐denatured enzyme pointing to a speciric reaction in the oxygen‐reducing centre of cytochrome c oxidase. The data support a hypothesis on a catalase cycle catalysed by cylochrome c oxidase in the presence of excess H 2 O 2 (Vygodina and Konstantinov (1988) Ann. NY Acad. Sci., 550, 124‐138);