title: The electron-transport system of mitochondria from the slime mould Physarum polycephalum.
abstract: A method is described for the preparation of mitochondria from the slime mould Physarum polycephalum; the mitochondria were not coupled. P. polycephalum mitochondria oxidized added NADH via a rotenone-insensitive pathway, but the oxidation of malate plus glutamate was rotenone sensitive; both of these substrates reduced much less cytochrome b than did succinate, in both aerobic and anaerobic steady states. Spectroscopy at 77 degrees K separated three absorption maxima in the alpha-band region, at 560nm, 553nm and one at 547nm due to cytochrome c. The absorption at 553nm was increased in the aerobic steady state by the addition of 2-heptyl-4-hydroxyquinoline N-oxide, suggesting that it was due to a b-type cytochrome. All three absorption maxima appeared in the aerobic steady state after the addition of a range of substrates. The respiratory activity with different substrates and the response to inhibitors of respiration were similar to those previously described for fungus mitochondria (Weiss et al., 1970; Erickson & Ashworth, 1969). When grown under conditions of haem limitation the mitochondria contained a lower concentration of cytochromes than normal.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000968:Antimycin A / Q000494:pharmacology; D003486:Cyanides / Q000494:pharmacology; D003580:Cytochromes / Q000378:metabolism; D004579:Electron Transport; D005971:Glutamates / Q000378:metabolism; D008293:Malates / Q000378:metabolism; D008314:Malonates / Q000494:pharmacology; D008928:Mitochondria / Q000378:metabolism*; D009235:Myxomycetes / Q000378:metabolism*; D009243:NAD / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D012402:Rotenone / Q000494:pharmacology; D013057:Spectrum Analysis; D013386:Succinates / Q000378:metabolism
chemical_list: D003486:Cyanides; D003580:Cytochromes; D005971:Glutamates; D008293:Malates; D008314:Malonates; D013386:Succinates; D012402:Rotenone; D009243:NAD; D000968:Antimycin A; D000255:Adenosine Triphosphate; D010100:Oxygen