title: The electron transport chain of Rhizobium trifolii.
abstract: The presence of a branched respiratory chain in Rhizobium trifolii grown in batch culture on a defined medium was demonstrated. The branches of the respiratory chain differ in sensitivity to inhibition by cyanide and in affinity for oxygen. The branching point is localized at cytochrome b-555. Electron flow from cytochrome b-555 via cytochrome c-549 and cytochrome a-597 towards oxygen has a relatively low affinity for oxygen and is sensitive to inhibition by cyanide. The second terminal oxidase is cytochrome b-561, which is directly linked to cytochrome b-555. This pathway has a higher affinity for oxygen. The pathway via cytochrome a-597 is more efficient in energy conservation than the pathway via cytochrome b-561, which lacks site III of oxidative phosphorylation.
mesh_terms: D000968:Antimycin A / Q000494:pharmacology; D003486:Cyanides / Q000494:pharmacology; D003580:Cytochromes / Q000378:metabolism*; D004579:Electron Transport / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009243:NAD / Q000378:metabolism; D010085:Oxidative Phosphorylation; D010101:Oxygen Consumption / Q000187:drug effects; D012231:Rhizobium / Q000378:metabolism*; D013053:Spectrophotometry
chemical_list: D003486:Cyanides; D003580:Cytochromes; D009243:NAD; D000968:Antimycin A