Triphosphopyridine nucleotide: cytochrome C reductase of Saccharomyces Cerevisiae a “microsomal” enzyme

• Published in: Biochimica et biophysica acta Vol. 81; no. 3; pp. 448 - 461
• Main Authors: Schatz, Gottfried, Klima, Jörg
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 09.03.1964
• Subjects: Cell Biology; Cytochromes; Cytochromes c; Cytoplasmic Granules; Electron Transport; Electrons; Lactates; Metabolism; Microscopy; Microscopy, Electron; Microsomes; NAD; NADH Dehydrogenase; NADP; Old Medline; Oxidoreductases; Saccharomyces; Saccharomyces cerevisiae; LACTATES; EXPERIMENTAL LAB STUDY; SACCHAROMYCES; MICROSCOPY, ELECTRON; CYTOLOGY; ELECTRON TRANSPORT; NAD; CYTOCHROMES; CYTOPLASMIC GRANULES; METABOLISM; MICROSOMES; NADP; OXIDOREDUCTASES
• ISSN: 0926-6569; 0006-3002; 1878-2248
• DOI: 10.1016/0926-6569(64)90130-0

1. 1. The intracellular location and function of TPNH: cytochrome c reductase (EC 1.6.2.3) and of DPNH; cytochrome c reductase system in the yeast cell have been investigated. 2. 2. Both enzyme activities are associated with particles. 3. 3. Homogenates of anaerobically grown yeast and of the “petite” mutant, both of which are unable to respire, exhibit practically the same specific TPNH: cytochrome c reductase activity as homogenates of respiring baker's yeast. TPNH: cytochrome c reductase activity in antimycin-insensitive, does not interact with endogenous cytochrome c of yeast mitochondria and is predominantly associated with microsomal particles which have not yet been described for yeast. Electron micrographs of these particles are presented. 4. 4. In contrast, DPNH: cytochrome c reductase activity, which is greatly lowered in homogenates of anaerobic or “peptide” mutant yeast, is 95% inhibited by antimycin and interacts rapidly with endogenous cytochrome c of yeast mitochondria. More than 95% of this reductase activity is mitochondrial, the remainder being located in microsomes. Microsomal DPNH: cytochrome c reductase activity is not inhibited by antimycin. 5. 5. It is concluded, that TPNH: cytochrome c reductase of Saccharomyces cerevisine is not a respiratory-chain enzyme. Some implications of these findings are discussed.