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

The effects of the title compound (BOA) on energy-linked reactions in mitochondria were studied. BOA inhibited electron transfer between the flavin and ubiquinone in Complex I, and ATP synthesis at the F1 moiety of the ATPase complex. These results are discussed in relation to the toxicity of BOA towards a wide range of aerobic organisms.
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PMID:Inhibition of energy metabolism by benzoxazolin-2-one. 295 49

1. Assay conditions are described for the ATP-dependent, uncoupler-sensitive, energy-linked reduction of NAD(+) by succinate, dl-alpha-glycerophosphate or d-lactate in membranes from aerobically grown Escherichia coli. 2. The reaction may be demonstrated in electron-transport particles (ET particles) from cells grown in glycerol, but not in depleted particles washed in low-ionic-strength buffer, or in ET particles from cells grown in glucose. 3. The latter two classes of particles have low specific activities of ATPase (adenosine triphosphatase), succinate dehydrogenase, dl-alpha-glycerophosphate dehydrogenase and d-lactate dehydrogenase relative to undepleted ET particles from cells grown in glycerol. 4. Reconstitution of energy-linked NAD(+) reduction in particles from cells grown in glucose was done by: (a) addition of the high-speed supernatant fraction from sonicates of the same cells; (b) addition of a protein fraction, precipitated by (NH(4))(2)SO(4) from this supernatant, or (c) addition of an (NH(4))(2)SO(4)-precipitated fraction from the low-ionic-strength wash of particles from cells grown in glycerol. 5. The use of (NH(4))(2)SO(4)-precipitated fractions from ATPase- or succinate dehydrogenase-deficient mutants grown in glycerol in the above reconstitution indicated that failure to demonstrate the reaction in particles from cells grown in glucose was a result of inadequate activities of appropriate dehydrogenases, rather than of ATPase. 6. Energy-linked NAD(+) reduction could be demonstrated in particles from a ubiquinone-deficient mutant only after restoration of NADH oxidase activity by adding ubiquinone-1. 7. The measured rate of the energy-linked reaction in particles from a haem-deficient mutant, however, was not stimulated after the ATP- and haematin-dependent acquisition of functional cytochromes. 8. Results are interpreted as evidence of the ubiquinone-dependent, but cytochrome-independent, nature of the site I region of the respiratory chain in E. coli.
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PMID:Energy-linked reduction of nicotinamide--adenine dinucleotide in membranes derived from normal and various respiratory-deficient mutant strains of Escherichia coli K12. 415 32

1. Energy-linked and non-energy-linked transhydrogenase activities were assayed in membrane preparations from normal Escherichia coli K 12 and from various mutant strains. 2. The energy-linked transhydrogenase, which uses ATP as energy source, was dependent for activity on the presence of a functional Mg(2+)+Ca(2+)-stimulated adenosine triphosphatase. 3. Neither of the quinones formed by E. coli, namely ubiquinone-8 and menaquinone-8, was required for normal ATP-dependent energy-linked transhydrogenase activity. 4. The energy-linked transhydrogenase was inhibited by piericidin A at a site unrelated to the sites of inhibition of the electron-transport chain by piericidin A.
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PMID:The energy-linked transhydrogenase reaction in respiratory mutants of Escherichia coli K12. 433 91

The subcellular distribution of cytochrome b and ubiquinone in resting human neutrophils was investigated by rate zonal sedimentation of postnuclear supernatants on continuous sucrose gradients. Both cytochrome b and ubiquinone were mainly localized in small organelles, tertiary granules, that were resolved from the specific and azurophilic granules as well as from the cell membrane fraction. This cytochrome b- and ubiquinone-rich granule was shown to contain dicyclohexylcarbodiimide (DCCD)-sensitive, Mg2+-dependent ATPase as well as low amounts, less than a third, of the acid hydrolases beta-glucuronidase and N-acetyl-beta-glucosaminidase. Cytochrome b was also found in smaller proportions in plasma membranes and specific granules. A significant proportion of the ubiquinone was located in the region of the gradients where specific granules and mitochondria sedimented. However, quantitative measurements of oligomycin-sensitive ATPase indicated that this second localization of ubiquinone could not be entirely attributed to mitochondrial contamination. Plasma membrane contained small amounts of ubiquinone. In addition, the existence and location of a putative proton pump ATPase were also investigated. The ATPase was mainly located in the plasma membrane and in the upper half of the gradients (tertiary and specific granules), with the highest specific activity occurring in the tertiary granules. This activity was inhibited by 100 microM DCCD. Furthermore, ATP-dependent uptake of [14C]methylamine by tertiary and specific granules was observed. These results suggest that the DCCD-sensitive ATPase may function as a proton pump. DCCD inhibited the release of enzymes from specific granules that occurred when human neutrophils were activated by phorbol myristate acetate. However, higher concentrations of DCCD were required to achieve the same degree of inhibition of O2 uptake (I50 of 0.4 mM for secretion versus 1 mM for O2 uptake). These results suggest that specific granules do not play a crucial role in oxygen metabolism.
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PMID:Subcellular localization of cytochrome b and ubiquinone in a tertiary granule of resting human neutrophils and evidence for a proton pump ATPase. 614 82

A histochemical study of the metabolism of rat renal arteries and arterioles. Rat renal arteries and arterioles were examined histochemically to determine their metabolic profiles. Succinate, malate and NAD-isocitrate dehydrogenase, cytochrome oxidase and ubiquinone were assessed to determine aerobic metabolism. Glucose-6-phosphate dehydrogenase and DPN diaphorase were evaluated to determine hexose-monophosphate-shunt activity. Anaerobic metabolism was evaluated via lactate dehydrogenase, and the substrate, glycogen. Gomori's lipase, beta-hydroxybutyrate dehydrogenase and amounts of neutral fat and free fatty acids were assessed as indicators of lipid utilization. Myosin ATPase activity was evaluated as an index of ATP utilization for contraction. Deoxyribonucleic and ribonucleic acids were appraised as indicators of protein synthesis. In general, the oxidative enzymes and myosin ATPase demonstrate considerable activity in renal arteries and arterioles which suggests aerobic metabolism and ATP usage. Renal arteries and arterioles also appear capable of anaerobic metabolism as indicated by strong lactate dehydrogenase reactivity and by the presence of slight to moderate quantities of glycogen, while high levels of glucose-6-phosphate dehydrogenase and moderate amounts of deoxyribonucleic acid suggest a potential for beta-hydroxybutyrate dehydrogenase, minimal lipase activity, and the absence of fatty acids with substantial amounts of neutral fat, indicate limited lipid catabolism.
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PMID:A histochemical study of the metabolism of rat renal arteries and arterioles. 620 11

The antitumour antibiotic, adriamycin, inhibited oxidative phosphorylation in freshly prepared mitochondria from the heart, liver and kidney of the rat. It abolished respiratory control and stimulated ATPase activity. Succinate oxidation by heart mitochondria was extremely sensitive to the drug when hexokinase was present in the reaction medium. The sensitive site has been identified to lie in the region between the succinate dehydrogenase flavoprotein and ubiquinone of the respiratory chain.
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PMID:Inhibition of mitochondrial oxidative phosphorylation by adriamycin. 621 26

The effect of lonidamine, an antispermatogenic and antitumor drug, on the oxygen consumption, ATPase activity, and redox state of the electron carriers of Ehrlich ascites tumor mitochondria has been studied. Lonidamine inhibits ADP- and uncoupler-stimulated respiration on various NAD- and FAD-linked substrates, but does not affect state 4 respiration. Experiments to determine its site of action showed that lonidamine does not significantly inhibit electron flow through cytochrome oxidase. Electron flow through site 2, the ubiquinone-cytochrome b-cytochrome c1 complex, also was unaffected by lonidamine, which failed to inhibit the oxidation of duroquinol. Moreover, inhibition of electron flow through site 2 was also excluded because of the inability of the N,N,N',N'-tetramethyl-p-phenylenediamine bypass to relieve the lonidamine inhibition of the oxidation of pyruvate + malate. The F0F1ATPase activity and vectorial H+ ejection are also unaffected by lonidamine. The inhibition of succinate oxidation by lonidamine was found to take place at a point between succinate and iron-sulfur center S3. Spectroscopic experiments demonstrated that lonidamine inhibits the reduction of mitochondrial NAD+ by pyruvate + malate and other NAD-linked substrates in the transition from state 1 to state 4. However, lonidamine does not inhibit reduction of added NAD+ by submitochondrial vesicles or by soluble purified NAD-linked dehydrogenases. These observations, together with other evidence, suggest that electron transport in tumor mitochondria is inhibited by lonidamine at the dehydrogenase-coenzyme level, particularly when the electron carriers are in a relatively oxidized state and/or when the inner membrane-matrix compartment is in the condensed state. The action of lonidamine in several respects resembles the selective inhibition of electron transport in tumor cells produced by cytotoxic macrophages (D. L. Granger and A. L. Lehninger (1982) J. Cell Biol. 95, 527).
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PMID:Action of the antitumor and antispermatogenic agent lonidamine on electron transport in Ehrlich ascites tumor mitochondria. 622 86

A gentamicin-resistant mutant of Pseudomonas aeruginosa PAO503 was selected after ethyl methane sulfonate mutagenesis. The strain, P. aeruginosa PAO2401 had increased resistance to all aminoglycosides tested but exhibited no change for other antibiotics. The mutation designated aglA (aminoglycoside resistance) was 50% cotransducible with the 8-min ilvB,C marker on the P. aeruginosa chromosome. It showed a marked reduction in cytochrome c(552) and nitrate reductase (Nar) and a change in terminal oxidase activity. Cytochrome c(552) is a component of the P. aeruginosa Nar. No changes in succinate and reduced nicotinamide adenine dinucleotide dehydrogenases, ubiquinone content, Mg(2+)/Ca(2+) membrane adenosine triphosphatase, and energy coupling of electron transport to adenosine 5'-triphosphate synthesis were detected. Transport of gentamicin and dihydrostreptomycin was impaired in PAO2401, but transport of proline, arginine, glutamine, glucose or the polyamine spermidine was not reduced. Ribosomes of PAO2401, and PAO503 bound dihydrostreptomycin equally well, and cell extracts did not inactivate gentamicin or dihydrostreptomycin. Strain PAO2401 is resistant to gentamicin and dihydrostreptomycin because of impaired transport of these compounds. The transport studies indicate a selective coupling of dihydrostreptomycin and gentamicin transport with terminal electron transport. This conclusion was supported by results from another mutant (PAO417-T2) with increased Nar activity, enhanced dihydrostreptomycin and gentamicin transport and a reduction in resistance to these drugs. These results are discussed in relation to a refined model for aminoglycoside transport and briefly relative to plasmid-mediated aminoglycoside resistance.
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PMID:Aminoglycoside-resistant mutation of Pseudomonas aeruginosa defective in cytochrome c552 and nitrate reductase. 624 53

The effects of the decamethyloctadehydrocorrine-cobalt complex (Co-C) on respiration and the ATP-synthetase activity of rat liver mitochondria were investigated. The Co-C complex was found to be an effective shunt of the respiratory chain. It accepts electrons from ubiquinone and donates them directly to O2. The Co-C complex inhibits the ATPase and ATP-synthetase activities of mitochondria.
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PMID:[Effect of dehydrocorrine-cobalt complex on mitochondria]. 629 15

The extraction of ubiquinone from mitochondrial membranes produces alterations of ATPase activity including a reversible loss of oligomycin sensitivity which is restored by long-chain Q-homologs, Short-chain ubiquinones like Q3 produce a loss of oligomycin and dicyclohexyl carbodiimide (DCCD) sensitivity in submitochondrial particles. The effect shows uncompetitive or noncompetitive Kinetics with respect to oligomycin or DCCD respectively. Long-chain ubiquinones have a competitive effect with Q3, thus restoring oligomycin sensitivity; they behave, however, in about the same way as Q3 in lowering the DCCD sensitivity in submitochondrial particles. On the basis of these observations we suggest that ubiquinone may be a physiological modulator of ATPase activity in the mitochondrial membrane.
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PMID:Interaction between ubiquinone and ATPase in mitochondrial membranes. 645 18


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