Reversible dissociation of flavin mononucleotide from the mammalian membrane-bound NADH: ubiquinone oxidoreductase (complex I).
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 ( approximately 10(-8)M at pH 10.0).
Department of Biochemistry, School of Biology, Moscow State University, Moscow 119992, Russian Federation.
Irina S
IS
Gostimskaya
Vera G
VG
Grivennikova
Gary
G
Cecchini
Andrei D
AD
Vinogradov
D000818:Animals; D002417:Cattle; D042967:Electron Transport Complex I / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D005486:Flavin Mononucleotide / Q000378:metabolism*; D008929:Mitochondria, Heart / Q000187:drug effects / Q000201:enzymology; D051336:Mitochondrial Membranes / Q000187:drug effects / Q000201:enzymology*; D009243:NAD / Q000494:pharmacology; D012402:Rotenone / Q000494:pharmacology; D013367:Submitochondrial Particles / Q000187:drug effects / Q000201:enzymology; D013997:Time Factors
D012402:Rotenone; D009243:NAD; D005486:Flavin Mononucleotide; D042967:Electron Transport Complex I