Chapter 8 Mitochondrial ubiquinol—cytochrome c oxidoreductase
1992; Elsevier BV; Linguagem: Inglês
10.1016/s0167-7306(08)60176-3
ISSN1875-7901
AutoresGeorg BECHMANN, Ulrich Schulte, Hanns Weiss,
Tópico(s)Metabolism and Genetic Disorders
ResumoThis chapter discusses the mitochondrial ubiquinol-cytochrome c oxidoreductase. Quinol-cytochrome c (plastocyanine) oxidoreductase, also called “bc1 (b6f)-complex,” is one of the most ancient and ubiquitous electron transfer complexes. It is found in mitochondria, chloroplasts and cyanobacteria, photosynthetic bacteria, and many other prokaryotes. It is minimally composed of three subunits, cytochrome b (b6) carrying a low-and a high potential heme group, cytochrome c1 (f), and a high-potential iron-sulfur (FeS)-protein traditionally called “Rieske-protein.” The general function of the complex is electron transfer between two mobile redox carriers, ubiquinol and cytochrome c (c2) in mitochondria and some bacteria, or plastoquinol and plastocyanine in chloroplasts and cyanobacteria. This electron transfer is coupled to proton translocation, thus generating proton-motive force in the form of an electrochemical proton potential that can drive ATP synthesis. Mitochondria1 cytochrome reductase has been isolated from different mammalian tissues, the yeast Succharomyces cerevisiae, and the filamentous fungus Neurospora crassa. The original isolation procedures used cholate and deoxycholate for protein extraction and different salts for fractional protein precipitation. This method yields preparations of high purity and enzymatic activity although in aggregated states.
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