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)

Analysis of the mitochondrial DNA of a liverwort Marchantia polymorpha by electron microscopy and restriction endonuclease mapping indicated that the liverwort mitochondrial genome was a single circular molecule of about 184,400 base-pairs. We have determined the complete sequence of the liverwort mitochondrial DNA and detected 94 possible genes in the sequence of 186,608 base-pairs. These included genes for three species of ribosomal RNA, 29 genes for 27 species of transfer RNA and 30 open reading frames (ORFs) for functionally known proteins (16 ribosomal proteins, 3 subunits of H(+)-ATPase, 3 subunits of cytochrome c oxidase, apocytochrome b protein and 7 subunits of NADH ubiquinone oxidoreductase). Three ORFs showed similarity to ORFs of unknown function in the mitochondrial genomes of other organisms. Furthermore, 29 ORFs were predicted as possible genes by using the index of G + C content in first, second and third letters of codons (42.0 +/- 10.9%, 37.0 +/- 13.2% and 26.4 +/- 9.4%, respectively) obtained from the codon usages of identified liverwort genes. To date, 32 introns belonging to either group I or group II intron have been found in the coding regions of 17 genes including ribosomal RNA genes (rrn18 and rrn26), a transfer RNA gene (trnS) and a pseudogene (psi nad7). RNA editing was apparently lacking in liverwort mitochondria since the nucleotide sequences of the liverwort mitochondrial DNA were well-conserved at the DNA level.
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PMID:Gene organization deduced from the complete sequence of liverwort Marchantia polymorpha mitochondrial DNA. A primitive form of plant mitochondrial genome. 173 Oct 62

The effects of arachidonic acid on the enzyme complexes in the electron transport system were investigated using submitochondrial particles from rat brain. Arachidonic acid irreversibly inhibited NADH-CoQ oxidoreductase (complex I) activity, but had no effect on the activities of succinate-CoQ oxidoreductase (complex II), CoQH2-cytochrome c oxidoreductase (complex III), cytochrome c oxidase (complex IV), ATPase (complex V), glutamate dehydrogenase, and malate dehydrogenase up to 50 microM. The inhibition was dose-dependent with an IC50 value of 110 nmol/mg protein. The Lineweaver-Burk plot revealed that the inhibition by arachidonic acid was noncompetitive against CoQ with a Ki value of 33 microM and uncompetitive against NADH with a Ki value of 22 microM.
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PMID:Selective inhibition of NADH-CoQ oxidoreductase (complex I) of rat brain mitochondria by arachidonic acid. 190 30

An Escherichia coli mutant pleiotropically altered in membrane-bound oxidoreductase activities was isolated following nitrosoguanidine treatment. Mutant R23 was able to grow on glucose, but was unable to grow on succinate or other oxidizable substrates as a sole energy source. Isolated membranes prepared from R23 failed to oxidize succinate and formate; while NADH was oxidized at a reduced rate by membranes. The mutant also exhibited markedly reduced cytochrome content, but normal DL-lactate PMS reductase and H(+)-translocating ATPase activities relative to the parent strain. Bacteriophage Plkc was used to transduce R23 to growth on glycerol, DL-lactate or succinate; regardless of the selection procedure, each of the 179 transductants had gained the ability to grow on all three substrates. The suc- mutation in R23 appeared to be responsible for the loss of growth on oxidizable substrates, altered membrane-bound oxidoreductase activities, resistance to neomycin, and reduced levels of cytochrome components. The suc- mutation was localized in the 6 to 6.5 min region of the E. coli chromosome map utilizing episomal transfers.
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PMID:Characterization of an Escherichia coli mutant pleiotropically altered in membrane-bound oxidoreductase activities. 214 97

From the chemiosmotic hypothesis it follows that no change is expected in potency of an uncoupler to inhibit an energy-driven reaction in an energy-transducing membrane if the energy-requiring part of the reaction, the so-called secondary proton pump, is partially inhibited by a specific, tightly bound inhibitor. An increase in potency upon inhibition of the primary pump may be expected, due to a lower rate of the total proton flow that can be used by the secondary pump and dissipated by the uncoupler. Contrary to this prediction several uncouplers (S13, SF6847, 2,4-dinitrophenol, valinomycin + nigericin) show an increase in uncoupling efficiency in ATP-driven reverse electron transfer (reversal) upon inhibition of the secondary pump in this reaction, the NADH:Q oxidoreductase, by rotenone. The increase in uncoupling efficiency is proportional to the decrease in the rate of reversal, that is to the decrease in concentration of active secondary pump. Similarly, upon inhibition of the primary pump, the ATPase, with oligomycin, an increase in uncoupling efficiency was found, also proportional to the decrease in the rate of reversal. When the pore-forming uncoupler gramicidin was used, no change in uncoupling potency was found upon inhibition of NADH:Q oxidoreductase. Inhibition of the ATPase, however, resulted in a proportionally lower uncoupling titre for gramicidin, just as was found for S13 in the presence of oligomycin. A difference was also found in the relative concentrations of S13 and gramicidin required to stimulate ATP hydrolysis or to inhibit reversal. The amount of S13 needed to stimulate ATP hydrolysis was clearly higher than the amount needed to inhibit reversal. On the contrary, the titre of gramicidin for both actions was about the same. To explain these results we propose that gramicidin uncouples via dissipation of the bulk delta mu H+, whereas the carrier-type uncouplers preferentially interfere with the direct energy transduction between the ATPase and redox enzymes. This is in accordance with the recently developed collision hypothesis.
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PMID:Uncoupler-inhibitor titrations of ATP-driven reverse electron transfer in bovine submitochondrial particles provide evidence for direct interaction between ATPase and NADH:Q oxidoreductase. 242 68

1. Monoamine oxidase (amine: oxygen oxidoreductase [deaminating], EC 1.4.3.4) (MAO) and Na+/K+ ATPase (Na+/K+-ATPase, Mg2+-dependent ATP phosphohydrolase, EC 3,1,6,3) showed reciprocal relationship in their activity patterns during experimentally perturbed situations in vivo as well as in vitro. 2. M-signal hypothesis is proposed, which attempts at explaining the regulation of plasma membrane function by the intermediate of metabolic processes in the cell. This metabolic intermediate referred to as M-signal exercise its influence on the plasma membrane Na+/K+ ATPase which is responsible for the uptake process.
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PMID:M-signal hypothesis--metabolic modulation of membrane functions in rat brain. 255 Sep 97

In the experiment performed on 52 white male rats by means of light and electron microscopy, cytochemistry and biochemistry, it has been stated that bilateral removal of the testes inhibits proliferation of epitheliocytes in the collum of the proper gastric glands and their differentiation into the main exocrinocytes. This results in decreasing amount of the latter and in development of certain destructive processes in them. They concern mainly the protein-synthesizing apparatus and to a less degree the mitochondrial and lysosomal apparatus. RNA content, ATPase activity oxidoreductase of Krebs cycle and pentose-phosphate shunt decreases, and that of glycolysis increase. Pepsinogen synthesis and its extrusion are inhibited; this is accompanied with a decreased proteolytic activity of the gastric juice. Regenerative processes in the main exocrinocytes are also inhibited.
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PMID:[Morphocytochemical reaction of the main exocrinocytes of the proper gastric glands to orchiectomy]. 261 74

Liver mitochondria isolated from vanadate-administered rats showed increased (20-25%) rates of oxidation of both NAD(+)-linked substrates and succinate. Respiratory control index and ADP/O were unaffected by the treatment. Dormant and uncoupler-stimulated ATPase activity also was not affected by vanadate administration. Membrane-bound, electron-transport-linked dehydrogenase activities (both NAD(+)- and succinate-dependent) increased by 15-20% on vanadate treatment. Mitochondrial alpha-glycerophosphate dehydrogenase activity increased by 50% on vanadate administration. The above effects of vanadate on oxidoreductase activities could be prevented by the prior administration of antagonists to alpha-adrenergic receptors. Substrate-dependent H2O2 generation by mitochondria also showed an increase on vanadate administration.
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PMID:Increase in alpha-glycerophosphate dehydrogenase and other oxidoreductase activities of hepatic mitochondria on administration of vanadate to the rat. 262 57

Highly purified preparations of plasma membranes from control and ketoconazole-treated (1 microM, 120 h) epimastigotes of Trypanosoma cruzi have been obtained by cell disruption using abrasion with glass beads, differential centrifugation and isopycnic centrifugation in continuous, self-generating Percoll gradients. The purity of the preparation was ascertained by the specific activity 125I bound to the membranes obtained from enzymatically radiolabeled epimastigotes and by the alpha-methyl-mannoside sensitive binding of 125I-concanavalin A. The membranes form closed vesicles of 0.2-0.4 micron in diameter which display Mg2+ ATPase and acid phosphatase activities, but are devoid of 5'-nucleotidase and succinate-cytochrome c oxidoreductase; these vesicles can be strongly agglutinated by concanavalin A. The lipid order profiles of membranes from control and treated cells were compared with that present in egg phosphatidylcholine/ergosterol liposomes (84:16, mol/mol) by electron spin resonance spectroscopy of doxylstearic acid probes with the nitroxide group bound to carbon 5, 10, 12 and 16 of the stearic acid chain. Membranes from treated epimastigotes have a lipid order profile which resembles that of control plasma membranes near the polar surface (positions 5 and 10) but there is an abrupt decrease of order at position 12 and from there to the center of bilayer is highly disordered, even more than in pure lipid membranes. Consistent with these results, the leakage of L-[14C]glucose from membrane vesicles of ketoconazole-treated cells is much faster than that observed in vesicles obtained from control cells. These results indicate a strong alteration of the plasma membrane physical and biological properties due to the incubation of the parasite with the drug; this alteration is consistent with the accumulation of methylated precursors of ergosterol, which affects both lipid-lipid and lipid-protein interactions in the membrane.
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PMID:Alteration of lipid order profile and permeability of plasma membranes from Trypanosoma cruzi epimastigotes grown in the presence of ketoconazole. 284 68

The photoaffinity label 8-azido-ATP has been used to study the effect of inhibition of ATP synthase on ATP-driven reverse electron transfer from succinate to NAD+ ('reversal'), succinate- and NADH-driven ATP synthesis and ATP-Pi exchange. In reversal, where ATPase functions as primary proton pump, inactivation by covalently bound nitreno-ATP results in an inhibition that is proportional to the inactivation of ATP hydrolysis, or, consequently, with the concentration of inactivated ATP synthases. Up to 60% inactivation of the reversal rate does not lead to a decrease in delta mu H+. Inhibition of ATP synthase as secondary proton pump results in case of NADH-driven ATP synthesis in a proportional inhibition, but with succinate as substrate ATP synthesis is less than proportionally inhibited, compared with inactivation of ATP hydrolysis. Inhibition of one of the primary pumps of NADH-driven ATP synthesis, the NADH:Q oxidoreductase, with rotenone also resulted in an inhibition of the rate of ATP synthesis proportional to that of the NADH oxidation. ATP-Pi exchange is much more affected than ATP hydrolysis by photoinactivation with 8-azido-ATP. Contrary to reversal and NADH-driven ATP synthesis the rate of ATP-Pi exchange does not depend linearly, but quadratically on the concentration of active ATP synthases. The observed proportional relationships between inhibition of the primary or secondary pump and the inhibition of the overall energy-transfer reactions do not support the existence of a pool intermediate in energy-transduction reactions. However, the results are consistent with a direct transfer of energy from redox enzymes to ATP synthase and vice versa.
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PMID:Inhibition of energy-transducing reactions by 8-nitreno-ATP covalently bound to bovine heart submitochondrial particles: direct interaction between ATPase and redox enzymes. 286 15

The hydrophobic compound diethylstilbestrol inhibits the generation of the proton gradient and the membrane potential in chromatophores from Rhodospirillum rubum and dissipates proton gradients over asolectin vesicle membranes. The Ca2+-ATPase activity of chromatophores, of purified F0F1-ATPase and of purified F1-ATPase is also decreased in the presence of diethylstilbestrol. Other repressed activities are the pyrophosphatase activity of soluble pyrophosphatase from yeast and the NADH oxidation by L-lactate:NAD oxidoreductase. We have previously reported that also ATP synthesis, PPi synthesis and PPi hydrolysis of R. rubrum chromatophores are inhibited by diethylstilbestrol [Strid et al. (1987) Biochim. Biophys. Acta 892, 236-244]. Addition of bovine serum albumin reverses or prevents diethylstilbestrol-induced inhibition of the activities tested. On the other hand, the Mg2+-ATPase activity of chromatophores, purified F0F1-ATPase and purified F1-ATPase are stimulated by low concentrations of diethylstilbestrol. On the basis of its hydrophobicity and the reversal of its inhibition by bovine serum albumin, diethylstilbestrol is proposed to act unspecifically on membranes and at hydrophobic domains of proteins. Such an attack upon the subunits of the F1-ATPase, altering the subunit interactions, is proposed to explain the different results obtained for the Ca2+-ATPase and the Mg2+-ATPase.
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PMID:Diethylstilbestrol. Interactions with membranes and proteins and the different effects upon Ca2+- and Mg2+-dependent activities of the F1-ATPase from Rhodospirillum rubrum. 290 53


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