title: Evidence against proton pump activity by cytochrome c oxidase of Pseudomonas AM1.
abstract: Proteoliposomes reconstituted from purified cytochrome c oxidase of Pseudomonas AM1 and from a heptyl beta-D-thioglucoside-extract of its membranes showed respiratory control but did not show H+ pumping upon a pulse with reduced cytochrome c. The stoichiometries of respiration-dependent H+ translocation in the resting cells respiring ascorbate via N,N,N',N'-tetramethyl-p-phenylenediamine were measured by the oxygen-pulse and initial rate methods. The apparent H+/O ratio of about 2 was due to 2H+ release from the hydrogen-donating substrate. These results strongly suggested that Pseudomonas AM1 does not pump H+ intrinsically, although the enzyme catalyzes electron transfer across the membranes.
authors.affiliation: Department of Biochemistry, Jichi Medical School, Tochigi.
authors.forename: N
authors.initials: N
authors.lastname: Sone
authors.forename: M
authors.initials: M
authors.lastname: Sekimachi
authors.forename: Y
authors.initials: Y
authors.lastname: Fukumori
authors.forename: T
authors.initials: T
authors.lastname: Yamanaka
mesh_terms: D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010101:Oxygen Consumption; D011522:Protons; D011549:Pseudomonas / Q000201:enzymology* / Q000378:metabolism
chemical_list: D011522:Protons; D003576:Electron Transport Complex IV