PMID: 1315503May 15, 1992

Cytochrome b of fish mitochondria is strongly resistant to funiculosin, a powerful inhibitor of respiration

Archives of Biochemistry and Biophysics
M Degli EspostiA Meyer


We report here some unusual properties of ubiquinol: cytochrome c reductase of eel and other fish mitochondria. The turnover rate of the reductase is clearly higher than in mammalian mitochondria and the binding constant for ubiquinone seems to be larger than in other vertebrates. Additionally, the reductase activity of fish mitochondria is resistant to some powerful inhibitors that bind to cytochrome b, in particular to funiculosin. After sequencing most of the gene of eel cytochrome b and comparing the deduced amino acid sequence with that of other fish and animals, we hypothesize that the decreased binding of funiculosin could be due to a few amino acid replacements in the third and fourth transmembrane helix of the protein. In particular, the presence of methionine instead of alanine at position 125 seems to be largely responsible for the strong resistance to funiculosin and also to the partial resistance to myxothiazol in all fish mitochondria. Correlations between some residue substitutions in cytochrome b and the different effects of funiculosin in different species are also considered.


Sep 1, 1991·Archives of Biochemistry and Biophysics·M D Esposti, G Lenaz
May 31, 1990·European Journal of Biochemistry·M Degli EspostiG Venturoli
Dec 7, 1989·Biochimica Et Biophysica Acta·M D Esposti
Jun 12, 1989·Nucleic Acids Research·J R BrownM J Smith
Aug 1, 1989·Proceedings of the National Academy of Sciences of the United States of America·T D KocherA C Wilson
Jan 1, 1986·Comparative Biochemistry and Physiology. B, Comparative Biochemistry·M Degli EspostiG Lenaz


Oct 1, 1992·Comparative Biochemistry and Physiology. B, Comparative Biochemistry·A GhelliM Degli Esposti
Jun 3, 2000·Annual Review of Pharmacology and Toxicology·K B Wallace, A A Starkov
Dec 23, 2009·Biochimica Et Biophysica Acta·Edward A BerryNobuko Minagawa

Related Concepts

Funiculosin (anthraquinone)
Antibiotics, Antifungal
Cytochrome b Group
Protein Conformation

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