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)

1. The specific activity of rat and pig liver nuclear-envelope nucleoside triphosphatase (EC 3.6.1.3) decreases when the system is depleted of RNA. The activity can be restored by adding high concentrations of yeast RNA to the assay medium. 2. Exogenous RNA also increases the activity of the enzyme in control envelopes (not RNA-depleted). The effect appears to be largely specific for poly(A) and poly(G); it is not stimulated by rRNA or tRNA preparations, ribonuclease-hydrolysed RNA, AMP, or double- or single-stranded DNA. 3. Inhibitors of the enzyme, in concentrations at which half-maximal inhibition of the enzyme is achieved, do not affect the percentage stimulation of the enzyme by yeast RNA. 4. The simulation is abolished by the inclusion of 150 mM-KCl or -NaCl in the assay medium, but not by increasing the assay pH to 8.5. 5. The results are discussed in the light of the possible role of the nucleoside triphosphatase in vivo in nucleo-cytoplasmic ribonucleoprotein translocation. 6. It is proposed that poly(G)-stimulated Mg2+-activated adenosine triphosphatase activity should be adopted as an enzymic marker for the nuclear envelope.
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PMID:Ribonucleic acid stimulation of mammalian liver nuclear-envelope nucleoside triphosphatase. A possible enzymic marker for the nuclear envelope. 14 Dec 76

To better assess the significance of enzyme-deficient foci as putative premalignant lesions, parallel histochemical analyses of RNase and ATPase activities were carried out in serial sections of livers from rats fed 4-dimethylaminoazobenzene. The results showed that focal losses of RNase and canalicular ATPase activities occur simultaneously in congruent areas of liver parenchyma at early stages of carcinogenesis. Such foci presumably represent altered cells capable of progressing to neoplasia since the changes observed in this new cell population persist in developing tumors.
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PMID:Histochemical comparison of focal losses of RNase and ATPase activities in preneoplastic rat livers. 15 7

A comparative study of glucose-6-phosphatase, alcaline RNase, ATPase, inosine diphosphatase and 5'-nucleotidase activities in isolated rat liver and hepatoma-27 nuclei and nuclear envelopes was performed. The tumor nuclear membranes were shown to be free from G-6-Pase activity in contrast to the liver nuclear membranes. The nuclear RNase activity was strongly inhibited in the hepatoma and could be unmasked in the presence of 3-10(-4) M pCMB. Hepatoma nuclear and nuclear envelopes ATP-ase activity was found to be moderately decreased as compared to those of the normal tissue. The values of inosine diphosphatase activity in hepatoma were similar to those in liver. The role of the nuclear envelope in nuclear-cytoplasmic interactions as well as nuclear location of G-6-Pase are discussed.
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PMID:[Various enzymes of isolated nuclear membranes and cell nuclei of the liver and hepatoma 27 of rats]. 19 29

The localization of some enzymic activities in cell fractions of Ureaplasma urealyticum was studied. A quantitative evaluation of the effectiveness of several cell lysis procedures was obtained by using labeled membranes and sucrose density gradient centrifugation. Ultrasonic treatment was found to be the most effective procedure for lysing the cells, whereas digitonin and osmotic shock caused the lysis of only 70 and 50% of the cells, respectively. The localization of selected enzymes in Ureaplasma cells resembled that found in other Mycoplasma species. Adenosine triphosphatase, ribonuclease, deoxyribonuclease, and p-nitrophenylphosphatase activities were located exclusively in the membrane fraction, whereas urease and L-histidine ammonia-lyase were located in the cytoplasm.
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PMID:Cell fractions and enzymatic activities of Ureaplasma urealyticum. 21 22

The peripheral membrane protein fraction released by washing Acholeplasma laidlawii membranes with low-ionic strength buffers contained about 50% of the total membrane-bound ribonuclease and deoxyribonuclease activities. The ATPase, NADH oxidase and p-nitrophenylphosphatase activities remained bound to the membrane even when EDTA was added to the wash fluids, and thus appear to belong to the integral membrane protein group. Serving as a marker for peripheral membrane proteins, the membrane-bound ribonuclease activity was solubilized by bile salts much more effectively than the integral membrane-bound enzymes. On the other hand, the solubilized ribonuclease showed a much lower capacity to reaggregate with other solubilized membrane components to membranous structures. Yet, most of the ribonuclease molecules which were bound to the reaggregated membranes could not be released by low-ionic strength buffer. The reaggregated membranes differed from the native membranes in the absence of particles on their fracture faces obtained by freeze cleaving, and by their much higher labeling by the [125-I]lactoperoxidase iodination system. These results suggest that most of the proteins are exposed on the reaggregated membrane surfaces, with very little, if any, protein embedded in its lipid bilayer core. Enzyme disposition in the A. laidlawii membrane was studied by comparing the activity of isolated membranes with that of membranes of intact cells after treatment with pronase or with an antiserum to membranes. The data indicate the asymmetrical disposition of these activities, the ATPase and NADH oxidase being localized on the inner membrane surface, while the nucleases are exposed on the external membrane surface.
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PMID:Characterization of the mycoplasma membrane proteins. V. Release and localization of membrane-bound enzymes in Acholeplasma laidlawii. 23 52

The effect of combined administration of ethanol and manganese on the brain tissue of rats was investigated to evaluate the role of alcohol ingestion in inducing susceptibility to manganese poisoning. Ethanol and manganese alone and the combination of the two were administered orally daily to the rats for 30 days. Almost identical increase in the brain contents of manganese in rats receiving the metal alone and in combination with ethanol indicates that ethanol administration does not influence the accumulation of manganese in that organ. The copper contents of brain also increased to almost the same extent in these two groups. Synergistic effect of ethanol and manganese was noticed on increasing the activity of ATPase and RNase while marked antagonistic effect was observed on the activity of MAO. The mechanism and the significance of these neurochemical alterations occurring after the administration of ethanol and manganese have been discussed.
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PMID:The interaction between ethanol and manganese in rat brain. 43 81

The Mg-adenosinetriphosphatase (ATPase) in the thyroidal NaI-treated microsome fraction was activated by treatment with basic polyamino acids or trypsin, but not with acidic polyamino acids and basic proteins such as lysozyme and ribonuclease. The enzyme kinetics showed that the activation of trypsin or poly-L-lysine was due to an increase in the maximal velocity of the hydrolyzing reaction without a change in the affinity of the enzyme for its substrate. A break at about 25 degrees C was observed in the Arrhenius plots of Mg-ATPase in the trypsin- or poly-L-lysine treated preparations, but there was no break in the control preparation. These results suggest that the activating effect of trypsin or poly-L-lysine on Mg-ATPase activity in the thyroidal NaI-treated microsome fraction is related to the lipid environment surrounding the enzyme molecule in the thyroid cell membrane.
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PMID:Characterization of thyroidal membrane-bound Mg-adenosinetriphosphatase activated by trypsin or poly-L-lysine. 153 27

A high molecular weight (HMW) fraction of the 150,000 g supernatant of rat brain homogenates contains protein-tRNA complexes which are able to incorporate [3H]Arg and [3H]Lys into tRNA. The aminoacylation of tRNA(Arg) was found to be dependent on ATP and inhibited by RNase. Conversely, the aminoacylation of tRNA(Lys) did not require exogenous ATP and was resistant to RNase and ATPase. In HMW fractions of regenerating rat sciatic nerves, the charging of both tRNA(Arg) and tRNA(Lys) was resistant to RNase and ATPase and did not require exogenous ATP. Because sciatic nerves are rich in axoplasm and tRNAs are known to be present in axons, we tested the hypothesis that degradative enzyme-resistant, ATP-tRNA complexes were of axonal origin. In HMW fractions from rat liver (containing no axons), both tRNA(Arg) and tRNA(Lys) were sensitive to RNase and required exogenous ATP for charging. But, in similar fractions of axoplasm obtained from the giant axon of squid, both tRNAs were insensitive to RNase and ATPase and did not require exogenous ATP for charging. These results suggest that tRNAs in axons are present in protected HMW complexes and contain endogenous stores of ATP. The presence of ATP in the HMW complexes was demonstrated by the luciferase-luciferin assay for ATP. The nature of the protection of tRNAs from RNases was examined by dissociating proteins from HMW complexes by boiling, treating with proteinase K, or overhomogenizing the tissue. These procedures failed to render brain tRNA(Lys) susceptible to RNase. But phenol-extracted, ethanol-precipitated brain tRNA(Lys) was sensitive to RNase, suggesting that the protection of tRNA(Lys) may be by a protease- and heat-resistant polypeptide or by a nonproteinaceous mechanism.
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PMID:Evidence that axonal tRNAs are resistant to RNase and ATPase and can be aminoacylated in the absence of exogenous ATP. 153 73

The activity of the DNA packaging adenosine triphosphatase (ATPase) of the Bacillus subtilis bacteriophage phi 29 is dependent upon prohead RNA. The 174 nucleotide viral-encoded RNA is positioned on the head-tail connector at the portal vertex of the phi 29 precursor shell (prohead). Here, the RNA interacts with the ATP-binding gene 16 product (gp16) to constitute the DNA-packaging ATPase and initiate DNA packaging in vitro. Both the prohead connector (gene 10 product, gp10) and gp16 may utilize an RNA recognition motif characteristic of a number of RNA-associated proteins, and the binding of gp16 by proheads shields the prohead RNA from RNase A. The ATPase activity of gp16 is stimulated fourfold by RNA and tenfold by proheads with RNA. RNA is needed continuously for the gp16/RNA ATPase activity and is essential for the gp16/prohead ATPase activity. The prohead, with its connector, RNA and associated gp16 in an assembly-regulated configuration, hydrolyzes ATP and drives phi 29 DNA translocation.
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PMID:RNA dependence of the bacteriophage phi 29 DNA packaging ATPase. 170 Jan 32

The expression of the three alpha-isoforms of Na(+)-K(+)-adenosine triphosphatase (ATPase) was examined in rat brain and rat kidney by Northern blot analysis. All three isoforms were detected in brain tissue while alpha 1-isoform was observed in whole kidney, suggesting that either this isoform was solely expressed in this organ or that alpha 2- and/or alpha 3-isoforms were not detected only because of their restricted distribution among a minority of specialized tubular cells. To distinguish between these two possibilities, in situ hybridization with rat alpha 1-, alpha 2-, and alpha 3-ATPase cRNA was performed on rat kidney sections. Results show that alpha 1-isoform expression largely predominates in the loop of Henle, distal tubule, and cortical collecting tubule. The labeling was drastically reduced by preincubation of sections with RNase. A sense cRNA probe, used as control, did not hybridize. With alpha 2- and alpha 3-probes, the labeling was low and uniformly distributed. In contrast, these two isoforms were clearly expressed in the brain, together with alpha 1. We conclude that only alpha 1-isoform of the Na(+)-K(+)-ATPase is detectable along the rat nephron. Its expression predominates in the tubular segments known to have a high Na(+)-K(+)-ATPase activity.
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PMID:Localization of alpha-isoforms of Na(+)-K(+)-ATPase in rat kidney by in situ hybridization. 184


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