Adenine nucleotide-binding sites on mitochondrial F1-ATPase: studies of the inactive complex formed upon binding ADP at a catalytic site.
ADP-induced inhibition of mitochondrial F1-ATPase has been studied. It is shown that in the presence of magnesium and the absence of light, the photoaffinity ADP analog, 2-azido-ADP, induces a reversible inhibition of native F1 that is indistinguishable from that obtained with ADP. Photolysis of the inactive complex results in the predominant labeling of a catalytic-site peptide identified previously (Cross et al., 1987, Proc. Natl. Acad. Sci. USA 84, 5715-5719). Dissociation of the inactive complex formed between F1 and ADP is biphasic with a rapid azide-insensitive phase followed by a slow azide-sensitive phase (k approximately 3 x 10(-3) s-1). It is also shown that incubation of the ADP-inhibited enzyme with EDTA or phosphate does not result in release or migration of ADP from the catalytic site. However, it does convert the complex to a form that reactivates in the presence of 100 microM ATP at a rate too rapid to observe using manual mixing.
Chernyak
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BV
Department of Biochemistry and Molecular Biology, State University of New York, Syracuse 13210.
Cross
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RL
D000244:Adenosine Diphosphate / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D001386:Azides / Q000737:chemistry; D001665:Binding Sites; D002384:Catalysis; D002413:Cations, Divalent; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D006868:Hydrolysis; D008274:Magnesium / Q000378:metabolism; D008929:Mitochondria, Heart / Q000201:enzymology*; D009943:Organophosphorus Compounds / Q000378:metabolism; D010777:Photochemistry; D006180:Proton-Translocating ATPases / Q000037:antagonists & inhibitors / Q000378:metabolism*
D001386:Azides; D002413:Cations, Divalent; D009943:Organophosphorus Compounds; D000244:Adenosine Diphosphate; C022295:2-azidoadenosine 3',5'-diphosphate; D006180:Proton-Translocating ATPases; D008274:Magnesium