title: Bacterial respiration-linked proton translocation and its relationship to respiratory-chain composition.
abstract: 1. The relationship between chain composition and the efficiency of respiration-linked proton translocation was studied in nine bacterial species of widely differing taxonomic and ecological status. 2. All the bacteria investigated contained respiratory chain dehydrogenases, ubiquinone and/or menaquinone, cytochrome b and cytochrome oxidase aa3 and/or o. In addition, some of these organisms also contained pyridine nucleotide transhydrogenase and/or cytochrome c. 3. leads to H+/O ratios of whole cell suspensions oxidising endogenous substrates were in the approximate range 4-8 mol H+ translocated per g-atom oxygen consumed. It was concluded from the observed leads to H+/O ratios of cells loaded with specific substrates that proton-translocating loops 1 and 2 were present in all of the organisms investigated, but that loops 0 and 3 were dependent upon the presence of pyridine nucleotide transhydrogenase and cytochrome c respectively. 4. The wide range in energy conservation efficiency which was observed in these organisms is discussed in relation to their respiratory chain composition and natural habitat.
mesh_terms: D000150:Acinetobacter / Q000378:metabolism; D000421:Alcaligenes / Q000378:metabolism; D001407:Bacillus / Q000378:metabolism; D001419:Bacteria / Q000378:metabolism*; D003580:Cytochromes / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007711:Klebsiella pneumoniae / Q000378:metabolism; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D011549:Pseudomonas / Q000378:metabolism; D013045:Species Specificity
chemical_list: D003580:Cytochromes; D009243:NAD; D009249:NADP