Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.6.3.14 (ATP synthase)
7,042 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The fatty acid composition of the ole-1 and ole-1 petite mutants of Saccharomyces cerevisiae was manipulated by growing the organism in the presence of defined supplements of Tween 80 or by allowing cells that had first been grown in the presence of Tween 80 to deplete their unsaturated fatty acids by sequent growth in the absence of Tween 80. 2. The transition temperature of Arrhenius plots of mitochondrial ATPase (adenosine triphosphatase) increases as the unsaturated fatty acid content is lowered. 3. Cells require larger amounts of unsaturated fatty acids to grow on ethanol at lower temperatures. 4. Cells that stop growing owing to unsaturated fatty acid depletion at low temperatures are induced to grow further by raising the temperature and this results in a further depletion of unsaturated acids. This is due to a higher rate, but not a greater efficiency, of mitochondrial ATP synthesis. 5. Arrhenius plots of the passive permeability of mitochondria to protons between 4 and 37 degrees C are linear. The rate and the Arrhenius activation energy of proton entry increase greatly as the unsaturated fatty acid content is lowered. 6. Unsaturated fatty acid depletion has the same effects on the proton permeability of ole-1 petite mitochondria, indicating that the mitochondrially synthesized subunits of the ATPase are not involved in the enhanced rates of proton entry. 7. The adenylate energy charge of depleted ole-1 cells is greatly decreased by growth on ethanol medium. 8. The adenylate energy charge of isolated mitochondria is also lowered by unsaturated fatty acid depletion. 9. The results confirm that unsaturated fatty acid depletion uncouples oxidative phosphorylation in yeast both in vivo and in vitro, and is a consequence of changes in the lipid part of the membrane.
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PMID:The effects of unsaturated fatty acid depletion on the proton permeability and energetic functions of yeast mitochondria. 14 59

The reaction of 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole [NBD-Cl] with purified eel electrophax Na+ and K+ stimulated adenosine triphosphatase [(Na-K)ATPase] has been monitored by changes in the (Na-K)ATPase activity, the K+ stimulated p-nitrophenyl phosphatase [PNPase] activity, and the protein ultraviolet absorption spectrum. The NBD-Cl reacts with two tyrosine residues per mol of enzyme (approximately 6-7 nmol/mg of protein), as judged by changes in protein absorption spectra and incorporation of [14C]NBD-Cl. The modified tyrosine groups are located on the Mr = 95 000 polypeptide chain and react at different rates. Only one tyrosine modification is necessary for complete inhibition of (Na-K)ATPase activity, although both must be modified for complete inhibition of PNPase activity. Reversal of these modifications by 2-mercaptoethanol restores 65% of both activities. Na+ increases the rate of tyrosine modification, K+ decreases the rate, and ATP affords the more reactive tyrosine group complete protection. NBD-Cl modification of approximately 6-7 nmol of tyrosine groups/mg of protein results in a large decrease in ATP affinity as judged by equilibrium binding. These results are compared with similar results obtained from NBD-Cl modification of the coupling factors of oxidative phosphorylation and photophosphorylation. A model is presented suggesting an asymmetric arrangement of two 95 000 polypeptide chains with a single tyrosine residue at the ATP site.
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PMID:Reaction of (Na-K)ATPase with 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole: evidence for an essential tyrosine at the active site. 14 73

1. The use of 1,N6-ethenoadenosine 5'-triphosphate (epsilon-ATP), a synthetic, fluorescent analog of ATP, by whole rat liver mitochondria and by submitochondrial particles produced via sonication has been studied. 2. Direct [3H]adenine nucleotide uptake studies with isolated mitochondria, indicate the epsilon-[3H]ATP is not transported through the inner membrane by the adenine nucleotide carrier and is therefore not utilized by the 2,4-dinitrophenol-sensitive F1-ATPase (EC 3.6.1.3) that functions in oxidative phosphorylation. However, epsilon-ATP is hydrolyzed by a Mg2+-dependent, 2,4-dinitrophenol-insensitive ATPase that is characteristic of damaged mitochondria. 3. epsilon-ATP can be utilized quite well by the exposed F1-ATPase of sonic submitochondrial particles. This epsilon-ATP hydrolysis activity is inhibited by oligomycin and stimulated by 2,4-dinitrophenol. The particle F1-ATPase displays similar Km values for both ATP and epsilon-ATP; however, the V with ATP is approximately six times greater than with epsilon-ATP. 4. Since epsilon-ATP is a capable substrate for the submitochondrial particle F1-ATPase, it is proposed that the fluorescent properties of this ATP analog might be employed to study the submitochondrial particle F1-ATPase complex, and its response to various modifiers of oxidative phosphorylation.
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PMID:The extent of mitochondrial F1-ATPase and adenine nucleotide carrier activity with epsilon-ATP. 14 75

The homogeneous rat liver F1-ATPase preparation of Catterall and Pedersen (Catterall, W.A., and Pedersen, P.L. (1971) J. Biol. Chem. 246, 4987-4994) has been crystallized from a solution containing phosphate and ATP by precipitation with ammonium sulfate. Most of the resultant crystals are cubes of approximately 0.3 to 0.6 mm per side. X-ray precession photographs show that the crystals are rhombohedral, space group R32 (D37 NO155) with hexagonal cell dimensions a = 148 A, c = 368 A. The molecular weight of the asymmetric unit of the crystals is 190,000 or about half the molecular weight (384,000) of the rat liver enzyme indicating that the crystallographic 2-fold axes of symmetry coincide with a molecular symmetry axis. The crystals diffract to at least 3.5 A and therefore this is the first report of an ATPase preparation in which crystals suitable for x-ray analysis have been obtained.
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PMID:Adenosine triphosphatase from rat liver mitochondria. Crystallization and x-ray diffraction studies of the F1-component of the enzyme. 14 72

1. Citreoviridin was a potent inhibitor of the soluble mitochondrial ATPase (adenosine triphosphatase) similar to the closely related aurovertins B and D. 2. Citreoviridin inhibited the following mitochondrial energy-linked reactions also: ADP-stimulated respiration in whole mitochondria from ox heart and rat liver; ATP-driven reduction of NAD+ by succinate; ATP-driven NAD transhydrogenase and ATPase from ox heart submitochondrial particles. 3. The dissociation constant (KD) calculated by a simple law-of-mass-action treatment for the citreoviridin--ATPase complex was 0.5--4.2micron for ox-heart mitochondrial preparations and 0.15micron for rat liver mitochondria. 4. Monoacetylation of citreoviridin decreased its inhibitory potency (KD=2--25micron, ox heart; KD=0.7micron, rat liver). Diacetylation greatly decreased the inhibitory potency (KD=60--215micron, ox heart). 5. Hydrogenation of citreoviridin monoacetate diminished its inhibitory potency considerably. 6. No significant enhancement of fluorescence was observed when citreoviridin interacted with the mitochondrial ATPase.
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PMID:Citreoviridin, a specific inhibitor of the mitochondiral adenosine triphosphatase. 14 74

The membrane ATPase (EC 3.6.1.3) of Bacillus subtilis can be solubilized by a shock-wash process. Two procedures for purifying the solubilized enzyme are reported. A protease inhibitor, phenylmethane sulfonylfluoride, was introduced in the solubilization and purification step. The resultant ATPase purified by density gradient centrifugation has a molecular weight of 315 000, an s20,w of 13,4 and an amino acid composition very similar to bacterial ATPases already studied. After exposure to polyacrylamide gel electrophoresis in presence of sodium dodecyl sulphate (SDS), or 8 M urea or SDS-urea, the purified ATPase can be dissociated in two non-identical subunits of molecular weights 59 000 (alpha) and 57 000 (beta) with different charges. Kinetic studies showed that Ca2+ or Zn2+ are required for ATPase activity, although Mg2+ was uneffective. At optimal Ca2+ concentration, the Mg2+ has an inhibitory effect. The Km for ATP is 1.3 mM. Inhibitors of the oxydative phosphorylation, of the mitochondrial ATPase and of the (Na+ + K+)-ATPase are studied.
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PMID:Membrane ATPase of Bacillus subtilis. I. Purification and properties. 14 10

The parameters of the hydrolysis of ATP and several analogs by soluble mitochondrial ATPase were determined. Vmax of the reaction decreases within the range: 2'-desoxy-ATP greater than ATP greater than etheno-ATP greater than GTP greater than 3'-O-methylATP greater than UTP. ATP, 2'-desoxypATP, 3'O-methyl-ATP, GTP, and etheno-ATP are hydrolysed by soluble mitochondrial ATPase with close Km(app) values. CTP is not hydrolysed by the enzyme and does not inhibit the ATPase reaction at a concentration of 10(-2) M. Nucleoside triphosphate derivatives with an "open" ribose cycle 9-[1',5'-dihydroxy-4-(S)-hydroxymethyl-3'-oxapent-2' (R)-yl]adenyl-5'-triphosphate, and 1-[1',5'-dihydroxy-4'-(S)-hydroxymethyl-3'-oxapent-2'(R)-yl[cytosine-5'-triphosphate are effective inhibitors of ATPase (Ki approximately 5.10(-5)M). Mitochondrial ATPase binds the ATP analogs that have hydrocarbon radicals-(CH2)2-, -(CH2)3-, and (CH2)4- instead of the ribose residues: 9-(2'hydroxyethyl)adenyl-2'-triphosphate, 9-(3'-hydroxypropyl)-adenine-3'-triphosphate, and 9-(4'-hydroxybutyl)adenine-4'-triphosphyl)adenine-4'-triphosphate were not hydrolysed by the enzyme, although they inbibit the ATPase reaction (Ki 2.10(-4)M). 9-(2'-hydroxyethyl)adenine-2'-triphosphate is hydrolysed by ATPase eight times more slowly than ATP. It is suggested that the hydrolysis of the substrates of mitochondrial ATPase is- preceded by the binding of the substrates in a tense conformation in the active site of the enzyme.
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PMID:[Substrate specificity of soluble mitochondrial ATPase]. 14 22

1. Maximum heart mitochondrial ATPase activity is displayed in the presence of an ATP/Mg++ ratio of 0.6--1.2. Under these conditions, mercury ions inhibit ATPase activity of both the mitochondria and the isolated enzyme. In both cases, inhibition occurs within concentration limits of 1--1.5X10(-4) M. 2. The inhibitory effect of free Hg++ ions can be abolished by converting them to a complex with ethylenediaminetetraacetic acid [EDTA]. 3. The inhibitory effect of Hg++ ions on mitochondrial ATPase can be attributed to their nonspecific action on functional groups of the active centre or to breakdown of the quaternary structure of the protein molecule of the enzyme.
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PMID:Inhibition of mitochondrial ATPase by Hg++ ions. 15 Jun 9

1. The oxidation of linoleate by rat-liver mitochondria has been studied as a function of substrate concentration. The oxidation of other long-chain unsaturated fatty acids shows similar characteristics. 2. At low concentrations, linoleate is readily oxidized in the absence of carnitine. Its rate of activation by the intramitochondrial acyl-CoA synthetase (EC 6.2.1.2) and subsequent oxidation is limited by the availability of intra-mitochondrial ATP. 3. A gradual increase of the linoleate concentration leads to (i) a strong depression of the rate of linoleate oxidation, and (ii) uncoupling of respiratory-chain phosphorylation together with induction of a mitochondrial ATPase activity. At still higher linoleate concentrations this ATPase activity is lowered rather than further stimulated and, concomitantly, the rate of linoleate oxidation increases again. 4. Evidence is presented that the inhibition by linoleate of the ATPase activity occurs at the level of the ATPase complex itself. This oligomycin-like effect of linoleate allows intramitochondrial linoleate activation to take place at the expense of ATP derived from substrate-level phosphorylation. 5. At very high concentrations of linoleate, its detergent action predominates and causes a complete inhibition of respiration as well as an extensive stimulation of an oligomycin-insensitive, Mg2+-dependent ATPase activity. 6. Measurement of the binding of radioactively labelled linoleate by isolated mitochondria shows that, at a given ratio of linoleate to mitochondrial protein, the ratio of bound to added linoleate is dependent on the concentration of the mitochondria.
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PMID:The oxidation of long-chain unsaturated fatty acids by isolated rat liver mitochondria as a function of substrate concentration. 15 Aug 57

Studies of phenylglyoxal incorporation by beef-heart mitochondrial ATPase reveal one fast-reacting arginyl residue/enzyme molecule. Modification of this group proceeds at a rate which parallels the loss of enzymatic activity. Efrapeptin protects the arginyl residue from reaction with phenylglyoxal. The data suggest that efrapeptin binds at the catalytic site and blocks accessibility of an essential arginine at the adenine nucleotide binding site. The detection of a single, fast-reacting, essential arginine on an enzyme with multiple copies of the catalytic subunit, provides further evidence in support of the alternating site mechanism for ATP synthesis proposed by Kayalar et al. (Kayalar, C., Rosing, J., and Boyer, P.D. (1977) J.Biol. Chem. 252, 2486--2491).
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PMID:Efrapeptin prevents modification by phenylglyoxal of an essential arginyl residue in mitochondrial adenosine triphosphatase. 15 85


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