Abstract
The Saccharomyces cerevisiae succinate-ubiquinone reductase or succinate dehydrogenase (SDH) is a tetramer of non-equivalent subunits encoded by the SDH1, SDH2, SDH3, and SDH4 genes. In most organisms, SDH contains one or two endogenous b-type hemes. However, it is widely believed that the yeast SDH does not contain heme. In this report, we demonstrate the presence of a stoichiometric amount of cytochrome b562 in the yeast SDH. The cytochrome is detected as a peak present in fumarate-oxidized, dithionite-reduced mitochondria. The peak is centered at 562 nm and is present at a heme:covalent FAD molar ratio of 0.92+/-0.11. The cytochrome is not detectable in mitochondria isolated from SDH3 and SDH4 deletion strains. These observations strongly support our conclusion that cytochrome b562 is a component of the yeast SDH.
MeSH terms
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Animals
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Cytochrome b Group / analysis*
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Dithionite / metabolism
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Electron Transport Complex II
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Escherichia coli Proteins*
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Flavin-Adenine Dinucleotide / metabolism
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Fumarates / metabolism
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Fungal Proteins / genetics
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Gene Deletion
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Intracellular Membranes / drug effects
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Intracellular Membranes / enzymology
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Intracellular Membranes / metabolism
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Lactic Acid / metabolism
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Malonates / pharmacology
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Mice
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Mitochondria / drug effects
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Mitochondria / enzymology*
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Mitochondria / genetics
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Mitochondria / metabolism
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Multienzyme Complexes / chemistry*
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Oxidation-Reduction / drug effects
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Oxidoreductases / chemistry*
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Saccharomyces cerevisiae / drug effects
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Saccharomyces cerevisiae / enzymology*
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae / metabolism
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Spectrum Analysis
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Succinate Dehydrogenase / chemistry*
Substances
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Cytochrome b Group
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Escherichia coli Proteins
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Fumarates
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Fungal Proteins
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Malonates
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Multienzyme Complexes
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Flavin-Adenine Dinucleotide
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Dithionite
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Lactic Acid
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fumaric acid
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cytochrome b562, E coli
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malonic acid
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Oxidoreductases
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Electron Transport Complex II
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Succinate Dehydrogenase