Open AccessBacterial Respiration‐Linked Proton Translocation and Its Relationship to Respiratory‐Chain Composition
Author(s) -
JONES Colin W.,
BRICE Joan M.,
DOWNS Andrew J.,
DROZD Jan W.
Publication year - 1975
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1975.tb03994.x
Subject(s) - cytochrome c oxidase , cytochrome , respiratory chain , respiration , biochemistry , cytochrome b , oxidase test , biology , composition (language) , chromosomal translocation , oxygen , cytochrome c , chemistry , enzyme , mitochondrion , botany , organic chemistry , gene , phylogenetic tree , linguistics , philosophy
1 The relationship between respiratory 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 aa 3 and/or o. In addition, some of these organisms also contained pyridine nucleotide transhydrogenase and/or cytochrome c.3 →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 →+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.