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Different polypeptides of bovine heart cytochrome c oxidase are in contact with cytochrome c
Author(s) -
Bisson Roberto,
Montecucco Cesare
Publication year - 1982
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(82)81302-1
Subject(s) - cytochrome c oxidase , carbodiimide , protein subunit , cytochrome c , chemistry , cytochrome , cytochrome c peroxidase , cytochrome c1 , biochemistry , electron transport complex iv , hemeprotein , stereochemistry , cytochrome p450 reductase , enzyme , coenzyme q – cytochrome c reductase , heme , mitochondrion , gene
Two water‐soluble carbodiimides, differing in molecular dimensions, have been used to characterize the cytochrome c binding site of bovine heart cytochrome c oxidase. Several polypeptide components of the enzyme contain acidic residues which are modified by these reagents. Carboxyl groups present in subunit II, VII and polypeptide c, are protected from modification when cytochrome c , equimolar to oxidase, is added and they can cross‐link to the substrate once activated by the carbodiimide. Comparison of the modification patterns suggest that the most reactive residues are located on subunit II and VII, the former being also more exposed. The data obtained indicate that eventhough subunit II plays the major role in binding cytochrome c , at least two other lower M r polypeptides contribute to the cytochrome c binding domain.