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)

Exogenous and endogenously generated reduced pyridine nucleotides caused marked stimulation of O(2) uptake when added to treponemal cell-free extracts, which indicated that terminal electron transport was coupled to the consumption of O(2). Oxidation of reduced nicotinamide adenine dinucleotide (NADH) was shown to correlate stoichiometrically with O(2) reduction, suggesting that NADH was being oxidized through a mainstream respiratory chain dehydrogenase. Oxygen evolution in treponemal extracts was observed after the completion of O(2) uptake which was stimulated by exogenous NADH and endogenously generated reduced NAD phosphate. Oxygen evolution was inhibited by both cyanide and pyruvate, which was consistent with O(2) release from H(2)O(2) by catalase. The addition of exogenous H(2)O(2) to treponemal extracts caused rapid O(2) evolution characteristic of a catalase reaction. A spectrophotometric assay was used to measure ATP formation in T. pallidum cell-free extracts that were stimulated with NADH. P/O ratios from 0.5 to 1.1 were calculated from the amounts of ATP formed versus NADH oxidized. Phosphorylating activity was dependent on P(i) concentration and was sensitive to cyanide, N, N'-dicyclohexylcarbodiimide, and carbonyl cyanide m-chlorophenyl hydrazone. Adenine nucleotide pools of T. pallidum were measured by the firefly luciferin-luciferase assay. Shifts in adenine nucleotide levels upon the addition of NADH to cell-free extracts were impossible to evaluate due to the presence of NAD(+) nucleosidase. However, when whole cells, previously incubated under an atmosphere of 95% N(2)-5% CO(2), were sparged with air, ATP and ADP levels increased, while AMP levels decreased. The shift was attributed to both oxidative phosphorylation and to the presence of an adenylate kinase activity. T. pallidum was also found to possess an Mg(2+) - and Ca(2+) -stimulated ATPase activity which was sensitive to N, N' -dicyclohexylcarbodiimide. These data indicated a capability for oxidative phosphorylation by T. pallidum.
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PMID:Respiration and oxidative phosphorylation in Treponema pallidum. 2 9

Human erythrocyte membrane fragments were exposed to O3 over varying lengths of time. Ozone was found to have a deleterious effect on the ouabainsensitive ATPase (EC 3.6.1.3) in the membrane fragments. After 1 min of exposure to O3, which was generated at a rate of 4.0 mumol/min, ouabain-sensitive ATPase activity decreased to 26% of the control. Ouabain-insensitive ATPase was found to be unaffected by O3 exposure under the test conditions. Additions of ascorbic acid or cysteine, prior to O3 exposure, partially protected the enzyme from inactivation. However, the inactivating effect of O3 could not be reversed by addition of either ascorbic acid or cysteine after exposure. Superoxide dismutase or catalase did not afford significant protection. The enzyme could not be protected by Ellman's reagent. The inactivating effect of O3 on the ouabain-sensitive ATPase was also demonstrated in exposure of intact erythrocytes. No detectable change was observed in glycolytic activity in the hemolysate prepared from O3-treated erythrocytes, however. It was postulated that inactivation of the membrane ATPase by O3 may be responsible for the destructive effect of O3 on the red cell.
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PMID:Effect of ozone on erythrocyte membrane adenosine triphosphatase. 13 Sep 35

1. Homogenates of guinea-pig left ventricle were fractionated by differential pelleting and by centrifugation on continuous sucrose density gradients. 2. The principal subcellular organelles of myocardium, characterized by their marker enzyme content, were resolved by density gradient centrifugation in a small-volume zonal rotor. The equilibrium densities (p) of the principal organelles are (with marker enzymes in parentheses): sarcolemma, 1-12 (5'-nucleotidase); lysosomes, 1-16 (N-acetyl-beta-glucosaminidase); mitochondria, 1-17 (cytochrome oxidase); peroxisomes, 1-18 (catalase); cytosol (lactate dehydrogenase). 3. The subcellular distribution of various adenosine triphosphatase activities and previously unassigned enzymes was determined. Leucyl-beta-naphthylamidase and gamma-glutamyl transpeptidase showed both cytosol and sarcolemma components. Ca2+-dependent adenosine triphosphatase showed dual localization to the mitochondria and to the sarcolemma.
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PMID:Analytical subcellular fractionation of guinea-pig myocardium. 14 54

Crossed immunoelectrophoresis of Triton X-100-solubilized plasma membranes of Micrococcus lysodeikticus established the presence of 27 discrete antigens. Individual antigens were identified as membrane components possessing enzyme activity by zymogram staining procedures and by reactivity of certain antigens with a selection of four lectins in the crossed-immunoelectrophoresis (immunoaffinoelectrophoresis) system. Absorption experiments with intact, stable protoplasts and isolated membranes established the asymmetric nature of the M. lysodeikticus plasma membranes. Of the 14 antigens with determinants accessible solely on the cytoplasmic face of the membrane, four possessed individual dehydrogenase activities, and a fifth was identifiable as a component possessing adenosine triphosphatase (EC 3.6.1.3) activity. Evidence from absorption studies with isolated membranes suggested that antigens such as the adenosine triphosphatase complex were more readily accessible to reaction with antibodies than was succinate dehydrogenase (EC 1.3.99.1), for example. Twelve antigens were located on the protoplast surface as determined by antibody absorption, and the succinylated lipomannan was identified as a major antigen. At least five other antigens possessed sugar residues that interacted with concanavalin A. With the antisera generated to isolated membranes, there was no evidence suggesting that any of these antigens was not detectable on either surface of the plasma membrane. From absorption experiments with washed, whole cells of M. lysodeikticus, it was concluded that the immunogens on the protoplast surface were also detectable on the surface of the intact cell. However, some of the components such as the succinylated lipomannan appeared to be exposed to a greater extent than others. The cytoplasmic fraction from M. lysodeikticus was used as an antigen source to generate antibodies, and 97 immunoprecipitates were resolvable by crossed immunoelectrophoresis. In the cytoplasm-anticytoplasm reference immunoelectrophoresis pattern of precipitates, three of the immunoprecipitates unique to the cytoplasmic fraction were identifiable by zymogram staining procedures as catalase (EC 1.11.1.6), isocitrate dehydrogenase (EC 1.1.1.42), and polynucleotide phosphorylase (EC 2.3.7.8). The identification of membrane and cytoplasmic antigens (including the above-mentioned enzymes) provides a sensitive analytical system for monitoring cross-contamination and antigen distribution in cellular fractions.
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PMID:Membrane asymmetry and expression of cell surface antigens of Micrococcus lysodeikticus established by crossed immunoelectrophoresis. 14 22

In this study, enzyme activities of the pancreatic appendages of the ductus hepatoPancreas (the so-called "pancreas") in Sepia officinalis L. have been demonstrated by light and electron micicroscopical methods: Malate dehydrogenase, monoamine oxidase, acid phosphatase, beta-glucuronidase, adenosine triphosphatase and carbonic anhydrase were shown by the former, and monoamine oxidase, catalase, glutamic oxalacetic transaminase, choline esterase (non-specific), alkaline phosphatase, acid phosphatase and carbonic anhydrase by the latter technique. The correlation between enzyme activity and distribution, and the presumed function of the two pancreatic epithelia is discussed.
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PMID:The localization of enzyme activities in the pancreatic appendages of Sepia officinalis L. (Cephalopoda). 15 95

Activities of a broad spectrum of enzymes were studied histochemically in renal adenocarcinomas induced in young male F344 rats by chronic dietary administration of the carcinogen N(4'-fluoro-4-biphenylyl)acetamide. Enzymes included were: dehydrogenases of glucose-6-phosphate, lactate, succinate, malate, and alpha-glycerophosphate; peroxidase (catalase); glucose-6-phosphatase; alkaline and acid phosphatase; Mg2+ ATPase; 5'-nucleotidase; and aminopeptidase. Levels of enzyme activity were estimated visually and scored from 0 (not detectable) to a maximum of 5 (intense). Comparison of estimated activity for each enzyme was made between small neoplastic nodules (stage III tumors) and large adenocarcinomas (stage IV tumors) and between tumors and portions of normal proximal tubules in parenchyma of kidneys from untreated control rats. The results, which revealed nearly identical levels of activity for most enzymes in both stages III and IV tumors, suggested similar metabolic and biologic behavior of these lesions. However, when data for tumors were compared with data for normal proximal tubules, striking differences were observed consistent with: 1) a marked shift of energy metabolism from oxidative to glycolytic production of ATP, with a corresponding reduction in mitochondrial respiration; and 2) simplification of plasma membrane specializations that were possibly associated with a reduction or loss of transport function. These findings were compared with other histochemical, biochemical, and ultrastructural studies of renal adenocarcinomas in rats and man.
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PMID:Adenocarcinoma of the kidney. II. Enzyme histochemistry of renal adenocarcinomas induced in rats by N-(4'-fluoro-4-biphenylyl)acetamide. 18 77

Mitochondria were isolated from the cellular slime mold. Dictyoostelium discoideum, and partially purified by sucrose density gradient fractionation. The most purified mitochondrial fraction from the gradient contained essentially no contaminating lysosomes and minimal amounts of contaminating peroxisomes as determined by the marker enzymes N-acetyl-glucosaminidase and catalase. A mitochondrial fraction with the same amount of lysosomal and peroxisomal contamination was also isolated from cells which had been treated with ethidium bromide for 5 days. The most purified mitochondrial fraction from control and ethidium bromide-treated cells had an identical buoyant density of 1.181 to 1.182 g per ml, suggesting that treatment with the drug does not result in any drastic structural changes in the mitochondrial membrane which would affect its density. In the purified mitochondria from ethidium bromide-treated cells, the content of cytochromes a-a3 was decreased over 80% and that of cytochrome oxidase and oligomycin sensitive ATPase were reduced approximately 50%. By contrast, the specific activities of NADH and succinate dehydrogenases were identical in the purified mitochondria from control and ethidium bromide-treated cells. Previously, we had reported that the specific activities of these two enzymes had nearly doubled in whole cells maintained in ethidium bromide for a time equivalent to six or seven generations after growth had stopped (Stuchell, R. N., Weinstein, B. I., and Beattie, D. S. (1973) Fed. Eur. Biochem. Coc Lett. 37, 23-26). These results suggest that continued formation of new mitochondrial membranes, with an identical complement of succinate and NADH dehydrogenases, must occur despite the cessation of cell growth which occurs as a result of the ethidium bromide induced loss of mitochondrial enzymes. Consequently, the amount of mitochondria, or mitochondrial protein per cell, calculated from the activity of NADH and succinate dehydrogenases has increased nearly 50%. Possible models to explain the control of mitochondrial biogenesis are discussed to explain these results.
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PMID:Effects of ethidium bromide on the respiratory chain and oligomycin-sensitive adenosine triphosphatase in purified mitochondria from the cellular slime mold Dicyostelium discoideum. 23 33

Whole sheets of plasma membrane, each with their attached flagellum, were purified from Trypanosoma brucei. The method devised for their isolation included a new technique of cell breakage that used a combination of osmotic stress followed by mechanical sheer and avoided the problem of extreme vesiculation as well as the trapping of organelles in cell 'ghosts'. The purified membranes all contained the pellicular microtubular array. The antigenic surface coat was completely released from the plasma membrane during the isolation procedure. The membranes had a very high cholesterol/phospholipid ratio (1.54). A large proportion (42%) of the cellular DNA was recovered in the plasma-membrane fraction unless a step involving deoxyribonuclease treatment, which decreased the DNA content to less than 13%, was included before secrose-density gradient centrifugation. This step also aided the separation of plasma membranes from other cellular components. The ouabain-sensitive Na+ + K+-stimulated adenosine triphosphatase and adenylate cyclase co-purified with the plasma membranes. Although 5'-nucleotidase was thought to be a plasma-membrane component, it was easily detached from the membrane. The purified membranes were essentially free of L-alanine-alpha-oxoglutarate aminotransferase, L-asparte-alpha-oxoglutarate aminotransferase, malate dehydrogenase, oligomycin-sensitive adenosine triphosphatase, glucose 6-phosphatase, Mg2+-stimulated p-nitrophenyl phosphatase and catalase.
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PMID:The isolation and partial characterization of the plasma membrane from Trypanosoma brucei. 48 94

1. Theoretical considerations in continuous flow analysis by Walker, Shepherdson and McGowan have been applied to continuous flow radiorespirometry of 14C-glucoses to demonstrate ethanol response differences between water- and ethanol preferring mice. 2. Ethanol dosages in the n mols/kg range stimulated glucose utilization rates more in ethanol-than in water-preferring mice, while intermediate dosages (micron and low mmol/kg) produced equal stimulation but at different dosages. Pharmacological dosages (20-88 mmols/kg) inhibited glucose rates in water-preferring mice. The inhibition was released at 44 mmols/kg in ethanol-preferring mice. 3. Inhibition release was shown to be associated more with glucose carbons other than one, and considered consistent with a sodium-plus potassium-activated ATPase mechanism. 4. Intermediate ethanol dosage changes could be assigned to differences induced in glucose carbon one metabolism with H2O2-catalase and/or microsomal-ethanol-oxidizing systems (MEOS) mechanisms. 5. Our studies suggest that measurements of adenylate deaminase activities might clarify shifts in transaminations (human) and shifts in mononucleotides seen following chronic ethanol ingestion.
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PMID:Ethanol-host interactions determined by radiorespirometry of 14C glucoses. 86 81

Reactive oxygen intermediates (ROI) have been implicated in a variety of pathophysiological conditions, and vascular smooth muscle may be a site of damage in such oxygen toxicity. Mechanisms of the effects of these intermediates on vascular smooth muscle at the cellular level, however, have not been well studied. We have previously shown that xanthine oxidase (XO)-generated superoxide radicals (O2-.) inhibited the Ca(2+)-adenosine triphosphatase of vascular smooth muscle sarcoplasmic reticulum (SR) through mechanisms that do not involve H2O2 or hydroxyl radicals. In the present study, we report that the D-myo-inositol 1,4,5-trisphosphate (IP3)-induced Ca2+ release from bovine aortic SR was also affected by O2-(.). Hypoxanthine (100 microM) plus XO (10 mU/ml) in the presence of catalase (100 U/ml) stimulated the IP3-induced Ca2+ release from SR monitored using arsenazo III. At 10 microM IP3, the release was doubled by O2-. treatment. As a consequence of using the higher SR protein concentrations required to observe the Ca2+ release, this effect was independent of Ca2+ uptake inhibition induced by O2-(.). Since the effect of O2-. was not seen when a nonhydrolyzable analogue of IP3 was used to induce Ca2+ release, O-2. may be inhibiting the degradation processes of IP3.
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PMID:Superoxide stimulates IP3-induced Ca2+ release from vascular smooth muscle sarcoplasmic reticulum. 131 Feb 31


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