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 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

Incubation of mitochondria from Neurospora crassa and Saccharomyces cerevisiae with the radioactive ATPase inhibitor [14C]dicyclohexylcarbodiimide results in the irreversible and rather specific labelling of a low-molecular-weight polypeptide. This dicyclohexylcarbodiimide-binding protein is identical with the smallest subunit (Mr 8000) of the mitochondrial ATPase complex, and it occurs as oligomer, probably as hexamer, in the enzyme protein. The dicyclohexylcarbodiimide-binding protein is extracted from whole mitochondria with neutral chloroform/methanol both in the free and in the inhibitor-modified form. In Neurospora and yeast, this extraction is highly selective and the protein is obtained in homogeneous form when the mitochondria have been prewashed with certain organic solvents. The bound dicyclohexylcarbodiimide label is enriched in the purified protein up to 50-fold compared to whole mitochondria. Based on the amino acid analysis, the dicyclohexylcarbodiimide-binding protein from Neurospora and yeast consists of at least 81 and 76 residues, respectively. The content of hydrophobic residues is extremely high. Histidine and tryptophan are absent. The N-terminal amino acid is tyrosine in Neurospora and formylmethionine in yeast.
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PMID:The dicyclohexylcarbodiimide-binding protein of the mitochondrial ATPase complex from Neurospora crassa and Saccharomyces cerevisiae. Identification and isolation. 15 5

The effect of organic solvents on the beef heart mitochondrial ATP-base-catalyzed ATP and ITP hydrolysis was examined. It was observed that numerous organic solvents stimulated ATP hydrolysis while ITP hydrolysis was inhibited. Methanol at 20% (v/v) was found to stimulate ATP hydrolysis by over 300%, while at the same methanol concentration ITP hydrolysis was inhibited approximately 50%. In the presence of 20% methanol, ATP hydrolysis exhibited linear plots of 1/[ATP] vs. 1/v, while in the absence of methanol negative cooperativity was observed. These data can be interpreted to imply that the catalytic and regulatory sites of the mitochondrial ATPase are being dissociated 20% methanol. The effect of methanol on the hydrolysis of ATP and ITP was examined as a function of pH. It was found that, at high pH in totally aqueous solutions, the hydrolysis of ATP and ITP was inhibited, while the presence of 20% methanol either caused the hydrolytic rate to peak and remain constant above pH 8 (with ATP as substrate) or caused the rate of hydrolysis to continue to increase above pH 8 (when ITP was the substrate). These data are interpreted to indicate that an acidic group in the active site may be ionizing, limiting the ATPase-catalyzed hydrolytic rate, and, with 20% methanol, this ionization was inhibited.
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PMID:Effect of organic solvents on the beef heart mitochondrial adenosine triphosphatase. 15 24

The dicyclohexylcarbodiimide-binding protein of Aspergillus nidulans has been identified as the smallest subunit of the mitochondrial ATPase complex, and has a molecular weight of approximately 8000. It is extractable from whole mitochondria and from the purified enzyme in neutral chloroform/methanol, contains 30% polar amino acids, and the N-terminal amino acid has been identified as tyrosine. Using a double-labelling technique in the absence and presence of cycloheximide, followed by immunoprecipitation of the enzyme complex with antiserum against Neuospora crassa F1 ATPase, it has been shown that this subunit is synthesized on cytoplasmic ribosomes.
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PMID:Mitochondrial ATPase complex of Aspergillus nidulans and the dicyclohexylcarbodiimide-binding protein. 15 78

The F0 sector of the ATP synthase complex facilitates proton translocation through the membrane, and via interaction with the F1 sector, couples proton transport to ATP synthesis. The molecular mechanism of function is being probed by a combination of mutant analysis and structural biochemistry, and recent progress on the Escherichia coli F0 sector is reviewed here. The E. coli F0 is composed of three types of subunits (a, b, and c) and current information on their folding and organization in F0 is reviewed. The structure of purified subunit c in chloroform-methanol-H2O resembles that in native F0, and progress in determining the structure by NMR methods is reviewed. Genetic experiments suggest that the two helices of subunit c must interact as a functional unit around an essential carboxyl group as protons are transported. In addition, a unique class of suppressor mutations identify a transmembrane helix of subunit a that is proposed to interact with the bihelical unit of subunit c during proton transport. The role of multiple units of subunit c in coupling proton translocation to ATP synthesis is considered. The special roles of Asp61 of subunit c and Arg210 of subunit a in proton translocation are also discussed.
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PMID:H+ transport and coupling by the F0 sector of the ATP synthase: insights into the molecular mechanism of function. 133 Oct 39

Methanogenesis is restricted to a group of prokaryotic microorganisms which thrive in strictly anaerobic habitats where they play an indispensable role in the anaerobic food chain. Methanogenic bacteria possess a number of unique cofactors and coenzymes that play an important role in their specialized metabolism. Methanogenesis from a number of simple substrates such as H2 + CO2, formate, methanol, methylamines, and acetate is associated with the generation of transmembrane electrochemical gradients of protons and sodium ions which serve as driving force for a number of processes such as the synthesis of ATP via an ATP synthase, reverse electron transfer, and solute uptake. Several unique reactions of the methanogenic pathways have been identified that are involved in energy transduction. Their role and importance for the methanogenic metabolism are described.
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PMID:Energetics of methanogenesis studied in vesicular systems. 145 85

The presence of an ATPase on yeast peroxisomal membranes was studied by immunological methods. Western blot analysis of purified peroxisomal membranes from several yeasts revealed distinct cross-reaction with specific antibodies against the F1-part or the beta-subunit of the mitochondrial ATPase of Saccharomyces cerevisiae. This was not due to mitochondrial contamination as was demonstrated by analytical sucrose gradient centrifugation. Protein A-gold labelling carried out on Lowicryl-embedded methanol-grown Hansenula polymorpha using these antibodies did not result in significant staining. However, when organelles isolated from this yeast were successively incubated with antibodies and protein A-gold prior to embedding, specific labelling was observed on both the peroxisomal membrane and the membrane of damaged mitochondria but not on intact mitochondria. Specific labelling of the peroxisomal membrane was confirmed by freeze-fracture immunocytochemistry. In addition to the peroxisomal membrane, the mitochondrial membrane was also labelled in these experiments. Freeze-fracture immunocytochemistry was also successful for the localization of peroxisomal matrix proteins, e.g. alcohol oxidase and dihydroxyacetone synthase, and of mitochondrial membrane proteins, e.g. cytochrome c oxidase.
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PMID:Immunocytochemical demonstration of the peroxisomal ATPase of yeasts. 213 97

The F1 portion of H(+)-translocating ATPase as purified from membrane vesicles of Vibrio parahaemolyticus by a rapid procedure. The whole purification process (from culture of cells to purification of the enzyme) could be completed in 1 day. The F1-ATPase consists of five subunits (alpha, beta, gamma, delta and epsilon) like F1 of Escherichia coli and other microorganisms. The F1-ATPase of V. parahaemolyticus showed some interesting properties. Its activity was greatly stimulated by high concentrations (about 0.5 M) of SO4(2-), SO3(2-) and CH3COO-, their effects decreasing in this order. Among the anions tested, Cl- and NO3- were ineffective, or rather inhibitory, and cations had no significant effects. Ethanol (or methanol) stimulated the activity 2- to 3-fold. The activity was inhibited by 4-acetamido-4'-isothiocyanostilbene 2,2'-disulfonate (SITS) (an anion exchanger inhibitor), tetrachlorosalicylanilide (TCS) (an H+ conductor), azide and N-ethylmaleimide. Zinc inhibited the activity only slightly, although it strongly inhibited the ATPase activity in membrane vesicles.
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PMID:Rapid purification and characterization of F1-ATPase of Vibrio parahaemolyticus. 214 93

The F1F0-ATP synthase from the alkaliphilic Bacillus firmus OF4 was purified in a reconstitutively active form, in good yield and with a high specific ATPase activity when appropriately activated. The purification procedure involved octyl glucoside extraction of washed membrane vesicles in the presence of 20% glycerol and asolectin followed by ammonium sulfate fractionation and sucrose density gradient centrifugation. The purified preparation was resolved into seven bands by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, corresponding to the five F1 subunits, alpha, beta, gamma, delta, and epsilon, and to the b and c subunits of the F0. Two-dimensional sodium dodecyl sulfate-poly-acrylamide gel analysis revealed a candidate for the alpha subunit of F0. The MgATPase activity of B. firmus OF4 F1F0 was barely detectable but could be stimulated, optimally more than 100-fold, by sulfite, methanol, and octyl thioglucoside. The enzyme was inhibited by N,N'-dicyclohexylcarbodiimide and sodium azide, but not by aurovertin, an inhibitor of the F1 from Escherichia coli. The F1F0 reconstituted into proteoliposomes catalyzed ATPase activity, ATP-Pi exchange, and ATP-dependent delta pH and delta psi formation. ATP hydrolysis was stimulated by protonophores while the other activities were abolished by protonophores. These activities were neither dependent on added sodium ions nor significantly affected by them. F1F0 proteoliposomes made from crude octyl glucoside extracts that also contained the Na+/H+ antiporter were shown to catalyze ATP-dependent Na+ uptake that was completely sensitive to carbonyl cyanide m-chlorophenyl-hydrazone; Na+ uptake activity was absent in proteoliposomes containing more purified F1F0 but lacking the Na+/H+ antiporter. These data show that the F1F0 translocates protons and does not substitute Na+ for H+ in energy coupling.
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PMID:Purification and reconstitution of the F1F0-ATP synthase from alkaliphilic Bacillus firmus OF4. Evidence that the enzyme translocates H+ but not Na+. 217 11

Cyanobacterial (Spirulina platensis) photosynthetic membranes and isolated F1 ATPase were characterized with respect to ATP activity. The following results indicate that the regulation of expression of ATPase activity in Spirulina platensis is similar to that found in chloroplasts: the ATPase activity of Spirulina membranes and isolated F1 ATPase is mostly latent, a characteristic of chloroplast ATPase activity; treatments that elicit ATPase activity in higher plant chloroplast thylakoids and isolated chloroplast coupling factor (CF1) greatly stimulate the activity of Spirulina membranes and F1, and the cation specificity of chloroplast ATPase activity, e. g., light-induced membrane activity that is magnesium dependent and trypsin-activated CF1 activity that is calcium dependent, is also observed in Spirulina. Thus, an 8- to 15-fold increase in specific activity (to 13-15 mumol Pi min-1 mg chl-1) is obtained when Spirulina membranes are treated with trypsin (CaATPase) or with methanol (MgATPase): a light-induced, dithiothreitol-dependent MgATPase activity is also found in the membranes. Purified Spirulina F1 is a CaATPase when activated with trypsin (endogenous activity increases from 4 to 27-37 mumol Pi min-1 mg protein-1) or with dithiothreitol (5.6 mumol Pi min-1 mg-1), but a MgATPase when assayed with methanol (18-20 mumol Pi min-1 mg-1). The effects of varying calcium and ATP concentrations on the kinetics of trypsin-induced CaATPase activity of Spirulina F1 were examined. When the calcium concentration is varied at constant ATP concentration, the velocity plot shows a marked sigmoidicity. By varying Ca-ATP metal-nucleotide complex concentration at constant concentrations of free calcium or ATP, it is shown that the sigmoidicity is due to the effect of free ATP, which changes the Hill constant to 1.6 from 1.0 observed when the free calcium concentration is kept constant at 5 mM. Therefore not only is ATP an inhibitor but it is also an allosteric effector of Spirulina F1 ATPase activity. At 5 mM free calcium, the Km for teh Ca-ATP metal-nucleotide complex is 0.42 mM.
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PMID:Properties of the cyanobacterial coupling factor ATPase from Spirulina platensis. II. Activity of the purified and membrane-bound enzymes. 286 95


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