title: Characterisation of phosphate binding to mitochondrial and bacterial membrane-bound ATP synthase by studies of inhibition with 4-chloro-7-nitrobenzofurazan.
abstract: The effect of phosphate on the inhibition by 4-chloro-7-nitrobenzofurazan of the ATPase activity of the proton-translocating ATP synthase in heart submitochondrial particles was investigated. Binding of phosphate protected strongly against the inhibition. A dissociation constant of 0.2 mM was determined for the enzyme X Pi complex and shown to be independent of pH in the range 7.0-8.0. The protective effect of phosphate was mimicked by arsenate but not by sulphate or malonate. Similar results were obtained for the enzyme from Paracoccus denitrificans. 2,4-Dinitrophenol enhanced phosphate binding to the mitochondrial enzyme since the protective effect of phosphate was increased. The data are compatible with protection arising from binding of phosphate to a catalytic site.
authors.forename: J A
authors.initials: JA
authors.lastname: Perez
authors.forename: A J
authors.initials: AJ
authors.lastname: Greenfield
authors.forename: R
authors.initials: R
authors.lastname: Sutton
authors.forename: S J
authors.initials: SJ
authors.lastname: Ferguson
mesh_terms: D019297:2,4-Dinitrophenol; D009327:4-Chloro-7-nitrobenzofurazan / Q000494:pharmacology*; D025181:ATP Synthetase Complexes; D000244:Adenosine Diphosphate / Q000378:metabolism; D000818:Animals; D001149:Arsenates / Q000494:pharmacology; D001665:Binding Sites; D002417:Cattle; D002462:Cell Membrane / Q000201:enzymology; D004140:Dinitrophenols / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008929:Mitochondria, Heart / Q000201:enzymology*; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors* / Q000378:metabolism; D010069:Oxadiazoles / Q000494:pharmacology*; D010231:Paracoccus denitrificans / Q000201:enzymology; D010710:Phosphates / Q000378:metabolism* / Q000494:pharmacology; D010770:Phosphotransferases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006180:Proton-Translocating ATPases / Q000037:antagonists & inhibitors
chemical_list: D001149:Arsenates; D004140:Dinitrophenols; D009097:Multienzyme Complexes; D010069:Oxadiazoles; D010710:Phosphates; D000244:Adenosine Diphosphate; D010770:Phosphotransferases; D025181:ATP Synthetase Complexes; D006180:Proton-Translocating ATPases; D009327:4-Chloro-7-nitrobenzofurazan; D008274:Magnesium; C025657:arsenic acid; D019297:2,4-Dinitrophenol