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Query: EC:3.6.1.3 (ATPase)
 65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

ATP synthase preparations [complex V, proton-translocatin ATPase (adenosine triphosphatase) and oligomycin-sensitive ATPase ] contain stoicheiometric amounts of lipoic acid residues (up to 6mol of lipoic acid/mol of ATPase complex) and catalyse net ATP synthesis in an uncoupler-and oligomycin-sensitive reaction utilizing dihydrolipoate, oleoyl-CoA and oleic acid, or in a reaction utilizing oleoyl-S-lipoate. The terminal reactions of oxidative phosphorylation are thus analogous to those of substrate-level phosphorylation.
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PMID:Studies of energy-linked reactions. Net synthesis of adenosine triphosphate by isolated adenosine triphosphate synthase preparations: a role for lipoic acid and unsaturated fatty acids. 13 19

Ligand-binding studies with labelled triethyltin on yeast mitochondrial membranes showed the presence of high-affinity sites (KD = 0.6 micronM; 1.2 +/- 0.3 nmol/mg of protein) and low-affinity sites (KD less than 45 micronM; 70 +/- 20 nmol/mg of protein). The dissociation constant of the high-affinity site is in good agreement with the concentration of triethyltin required for inhibition of mitochondrial ATPase (adenosine triphosphatase) and oxidative phosphorylation. The high-affinity site is not competed for by oligomycin or venturicidin, indicating that triethyltin reacts at a different site from these inhibitors of oxidative phosphorylation. Fractionation of the mitochondrial membrane shows a specific association of the high-affinity sites with the ATP synthase complex. During purification of ATP synthase (oligomycin-sensitive ATPase) there is a 5-6-fold purification of oligomycin- and triethyltin-sensitive ATPase activity concomitant with a 7-9-fold increase in high-affinity triethyltin-binding sites. The purified yeast oligomycin-sensitive ATPase complex contains approximately six binding sites for triethyltin/mol of enzyme complex. It is concluded that specific triethyltin-binding sites are components of the ATP synthase complex, which accounts for the specific inhibition of ATPase and oxidative phosphorylation by triethyltin.
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PMID:Studies of energy-linked reactions. Localization of the site of action of trialkyltin in yeast mitochondria. 14 Dec 73

1. The synthesis of dibutylchloromethyltin chloride, a new covalent inhibitor of the mitochondrial ATP synthase [oligomycin-sensitive ATPase (adenosine triphosphatase)] complex is described, together with a method for preparing dibutylchloro[(3)H]methyltin chloride. 2. Studies with the yeast mitochondrial oligomycin-sensitive ATPase complex show that dibutylchloromethyltin chloride inhibits both the membrane-bound enzyme and also the purified Triton X-100-dispersed preparation. 3. F(1)-ATPase is not inhibited even at 500nmol of dibutylchloromethyltin chloride/mg of protein, and the general inhibitory properties are similar to those of triethyltin, oligomycin and dicyclohexylcarbodi-imide, known energy-transfer inhibitors of oxidative phosphorylation. 4. Binding studies with yeast submitochondrial particles show that dibutylchloromethyltin chloride antagonizes the binding of triethyl[(113)Sn]tin, indicating that there is an interaction between the two inhibitor-binding sites. 5. Unlike triethyltin, inhibition by dibutylchloromethyltin chloride is due to a covalent interaction which titrates a component of the inner mitochondrial membrane present at a concentration of 8-9nmol/mg of protein. 6. All of the labelled component can be extracted with chloroform/methanol (2:1, v/v), and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of the chloroform/methanol extract indicates that the labelled component has an apparent mol.wt. of 6000-8000. However, t.l.c. reveals the presence of only one labelled component which is lipophilic and non-protein and is distinct from the free inhibitor, mitochondrial phospholipids and the dicyclohexylcarbodi-imide-binding protein (subunit 9). 7. Inhibition of mitochondrial ATPase and oxidative phosphorylation is correlated with specific interaction with a non-protein lipophilic component of the mitochondrial inner membrane which is proposed to be a co-factor or intermediate of oxidative phosphorylation.
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PMID:Dibutylchloromethyltin chloride, a covalent inhibitor of the adenosine triphosphate synthase complex. 14 60

We report the finding of mitochondrial ATP-synthase deficiency in a child with persistent 3-methylglutaconic aciduria. The child presented in the neonatal period with severe lactic acidosis, which was controlled by Na-HCO3 and glucose infusions. During the 1st y of life, there were several episodes of lactic acidosis precipitated by infections or prolonged intervals between meals. The excretion of lactate in urine was variable, but there was a persistent high excretion of 3-methylglutaconic acid. The activity of 3-methylglutaconyl-CoA hydratase in fibroblasts was normal. The child had a hypertrophic cardiomyopathy and magnetic resonance images revealed hypoplasia of corpus callosum. The gross motor and mental development was retarded, but there were no other neurologic signs. Investigation of muscle mitochondrial function at 1 y of age revealed a severe mitochondrial ATP-synthase deficiency (oligomycin-sensitive, dinitrophenol-stimulated Mg2+ ATPase activity: 27 nmol x min-1 x (mg protein)-1, control range 223-673 nmol x min-1 x (mg protein)-1. The mitochondrial respiratory rate was low and tightly coupled. The respiratory rate was normalized by the addition of an uncoupler. Low Mg2+ ATPase activity was also demonstrated by histochemical methods. Morphologic examination revealed ultrastructural abnormalities of mitochondria. There was no deletion of mitochondrial DNA. The sequences of the ATP synthase subunit genes of mitochondrial DNA were in accordance with published normal sequences.
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PMID:Mitochondrial ATP-synthase deficiency in a child with 3-methylglutaconic aciduria. 128 64

Two catalytic structures of H(+)-motive ATP synthase (Fig. 1), the alpha 3 beta 3 oligomer (M(r) = 319,581) and alpha 1 beta 1 promoter (M(r) = 106,527) (Fig. 2), were isolated using high pressure liquid chromatography (Fig. 3) and polyacrylamide gel electrophoresis (Figs. 4 and 5). These were reconstituted from the alpha and beta subunits of thermophilic F1 (TF1), and the alpha 3 beta 3 oligomer was also crystallized. Common to both F1 and the alpha 3 beta 3 oligomer were the nucleotide specificity, the two Km values, the presence of protomer-oligomer activities, and the one-hit--one-kill phenomenon. A synchrotron experiment on the ATP hydrolysis cycle revealed the dynamic shrinkage and expansion of F1(44) that correspond, respectively, to the ATP-induced association and ADP-induced dissociation of the alpha 3 beta 3 oligomer. The oligomer, like mitochondrial F1 and TF1, exhibited two kinds of ATPase activity: one was cooperative and was inhibited by only one inhibitor per hexamer, and the other was inhibited by three inhibitors per hexamer.
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PMID:The alpha 3 beta 3 and alpha 1 beta 1 complexes of ATP synthase. 128 33

In this paper we report observations on kinetic and structural characteristics of mitochondrial ATP synthase of rat-heart after subcutaneous injection of isoproterenol. The results obtained indicate: a decrease of respiratory rate either in absence (state 4) or in presence (state 3) of oxidative phosphorylation; decrease of respiratory control ratio; decrease of ATP hydrolase activity in sonic submitochondrial particles; decrease of relative content of the catalytic subunit F1 with respect to the membrane sector F0. The data obtained are in favour of the hypothesis that isoproterenol causes structural and functional alterations of mitochondrial ATP synthase.
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PMID:[Isoproterenol causes changes in the mitochondrial energy metabolism in the rat heart]. 129 74

A collection of amino acid substitutions at residues Glu-32 and His-39 in the epsilon subunit of the Escherichia coli F1F0 ATP synthase has been constructed by cassette mutagenesis. Substitutions for residue Glu-32 appeared to cause abnormal inhibition of membrane-bound F1 ATPase activity, and replacement of His-39 by Arg, Val, and Pro affected F1F0 interactions.
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PMID:Mutations at Glu-32 and His-39 in the epsilon subunit of the Escherichia coli F1F0 ATP synthase affect its inhibitory properties. 134 13

Archaebacterial plasma membranes contain an ATPase acting in vivo as a delta mu H(+)-driven ATP synthase. While functional features and their general structural design are resembling F-type ATPases, primary sequences of the two large polypeptides from the catalytic part are closely related to V-type ATPases from eucaryotic vacuolar membranes. The chimeric nature of archaebacterial ATPase from Sulfolobus was investigated in terms of nucleotide interactions and related to specific sequence parameters in a comparison to well known F- and V-type ATPases. The study disclosed a general difference of F- and V-type ATPases at one class of the nucleotide binding sites.
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PMID:F-type or V-type? The chimeric nature of the archaebacterial ATP synthase. 138 79

Escherichia coli strain AN718 contains the alpha S373F mutation in F1F0-ATP synthase which blocks ATP synthesis (oxidative phosphorylation) and steady-state F1-ATPase activity. The revertant strain AN718SS2 containing the mutation alpha C373 was isolated and shown to confer a phenotype of higher growth yield than that of the wild type in liquid medium containing limiting glucose, succinate, or LB. Purified F1 from strain AN718SS2 was found to have 30% of wild-type steady-state ATPase activity and 60% of wild-type oxidative phosphorylation activity. Azide sensitivity of ATPase activity and ADP-induced enhancement of bound aurovertin fluorescence, both of which are lost in alpha S373F mutant F1, were regained in alpha C373 F1. N-Ethylmaleimide (NEM) inactivated alpha C373 F1 steady-state ATPase potently but had no effect on unisite ATPase. Complete inactivation of alpha C373 F1 steady-state ATPase corresponded to incorporation of one NEM per F1 (mol/mol), in just one of the three alpha subunits. NEM-inactivated enzyme showed azide-insensitive residual ATPase activity and loss of ADP-induced enhancement of bound aurovertin fluorescence. The data confirm the view that placement at residue alpha 373 of a bulky amino acid side-chain (phenylalanyl or NEM-derivatized cysteinyl) blocks positive catalytic cooperativity in F1. The fact that NEM inhibits steady-state ATPase when only one alpha subunit of three is reacted suggests a cyclical catalytic mechanism.
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PMID:F1-ATPase with cysteine instead of serine at residue 373 of the alpha subunit. 138 22

A study is presented on the role of F0 and F1 subunits in oligomycin-sensitive H+ conduction and energy transfer reactions of bovine heart mitochondrial F0F1 H(+)-ATP synthase. Mild treatment with azodicarboxylic acid bis(dimethylamide) (diamide) enhanced oligomycin-sensitive H+ conduction in submitochondrial particles containing F1 attached to F0. This effect was associated with stimulation of the ATPase activity, with no effect on its inhibition by oligomycin, and depression of the 32Pi-ATP exchange. The stimulatory effect of diamide on H+ conduction decreased in particles from which F1 subunits were partially removed by urea. The stimulatory effect exerted by diamide in the submitochondrial particles with F1 attached to F0 was directly correlated with a decrease of the original electrophoretic bands of a subunit of F0 (F0I-PVP protein) and the gamma subunit of F1, with corresponding formation of their cross-linking product. In F0 liposomes, devoid of gamma subunit, diamide failed to stimulate H+ conduction and to cause disappearance of F0I-PVP protein, unless purified gamma subunit was added back. The addition to F0 liposomes of gamma subunit, but not that of alpha and beta subunits, caused per se inhibition of H+ conduction. It is concluded that F0I-PVP and gamma subunits are directly involved in the gate of the F0F1 H(+)-ATP synthase. Data are also presented indicating contribution to the gate of oligomycin-sensitivity conferral protein and of another protein subunit of F0, F6.
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PMID:Role of F0 and F1 subunits in the gating and coupling function of mitochondrial H(+)-ATP synthase. The effect of dithiol reagents. 138 61


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