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Reversible dissociation of flavin mononucleotide from the mammalian membrane‐bound NADH:ubiquinone oxidoreductase (complex I)
Author(s) -
Gostimskaya Irina S.,
Grivennikova Vera G.,
Cecchini Gary,
Vinogradov Andrei D.
Publication year - 2007
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/j.febslet.2007.11.048
Subject(s) - flavin mononucleotide , submitochondrial particle , chemistry , rotenone , flavin group , oxidoreductase , nadh dehydrogenase , flavin adenine dinucleotide , flavoprotein , reductase , cofactor , stereochemistry , biochemistry , enzyme , photochemistry , mitochondrion , protein subunit , gene
Conditions for the reversible dissociation of flavin mononucleotide (FMN) from the membrane‐bound mitochondrial NADH:ubiquinone oxidoreductase (complex I) are described. The catalytic activities of the enzyme, i.e. rotenone‐insensitive NADH:hexaammineruthenium III reductase and rotenone‐sensitive NADH:quinone reductase decline when bovine heart submitochondrial particles are incubated with NADH in the presence of rotenone or cyanide at alkaline pH. FMN protects and fully restores the NADH‐induced inactivation whereas riboflavin and flavin adenine dinucleotide do not. The data show that the reduction of complex I significantly weakens the binding of FMN to protein thus resulting in its dissociation when the concentration of holoenzyme is comparable with K d (∼10 −8 M at pH 10.0).