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)

Rhodopseudomonas palustris is grown photosynthetically on thiosulfate. As pointed out earlier, the chromatophore deficient cell-free fraction S-144,000 catalyzes the thiosulfate-linked ATP-dependent reversal of electron transfer in anaerobiosis, thus providing reducing equivalents in the form of NADH. Under aerobic conditions, this fraction also catalyzes the oxidation of NADH, ferro-cytochrome c, or ascorbate. ATP, ADP, and PPi are active in retarding the aerobic electron flow. The electron retardation is stimulated by the addition of Mg2+ due to a Mg2+-stimulated ATPase present. The ATPase system in S-144,000 hydrolyzes ATP, ADP, and PPi. Similarly, ATP or ADP, or even PPi can function as energy sources in order to achieve the reduction of pyridine nucleotide. The ATPase turnover is diminished by NADH or NAD+. Admixture of ascorbate results in an increased ATPase activity. Exactly the enhanced amount of adenine nucleotide hydrolysis caused by the addition of ascorbate is inhibited by cyanide.
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PMID:Respiratory electron flow and ATPase system in photosynthetically grown Rhodopseudomonas palustris. 17 Jul 51

Nicotinamide adenine dinucleotides (NAD, NADH2, NADP, and NADPH2) levels decrease in myocardial dog tissue after the ligature of the coronary artery branch. The activity of a glycohydrolytic enzyme acting on NAD and releasing nicotinamide in an equivalent amount was of the same order of magnitude in infarcted tissue, irrespective of the time elapsed after the coronary artery occlusion, as it was in normal tissue. Most of the NAD contained in normal heart muscle was hydrolyzed as soon as the tissue was disrupted in a homogenizer, whereas no hydrolysis occurred when the whole fragment was incubated for 1 hour. The enzymatic activity was found mainly in a membranous fraction seperated at 17,000 x g by differential centrifugation. Acid phosphatase, K+ -activated phosphatase, and NA+-K+-ATPase specific activities were greater in this fraction. It is suggested that the structural disorganization of the heart elicited either in vitro or during the infarction process determines the conditions for a reaction between the enzyme which is localized in the membranes and the NAD which is mainly in the cytosol.
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PMID:Nicotinamide adenine dinucleotide degradation in infarcted cardiac muscle. 17 68

It is determined that ortho- and n-nitrophenol introduced into the stomach (0.80 and 0.11 g/kg, respectively) inhibit the activity of cytochrome oxydase (by 21% at an average), cause an increase in the content of NADH (by 35 and 27%) and a decrease in ATP (by 38 and 36%, respectively), split the oxidation and phosphorylation processes in the rat liver tissue. The content of NAD+, AMP and ADP, lactate, the activity of K+, Na+-ATPase and lactate dehydrogenase do not change.
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PMID:[Peculiarities of disturbances in oxidation and phosphorylation processes in rat liver under the effect of mononitrophenols]. 17 56

Thirty extraocular muscles (EOM) from 20 patients were evaluated by light microscopy (LM), electron microscopy (EM), and enzyme histochemistry (EZH). Twenty-one EOM were obtained from 13 patients with strabismus, 9 EOM from 4 patients undergoing eye surgery for other reasons and from 3 autopsy cases. One mum thick sections revealed marked variation in muscle fibre shape and size and in myofibrillar structure; also noted were small, hypertrophied, whorled, and ringbinden fibres. Dense and granular material in the central portion of some fibres and sarcomere disruption in 2--3 mum sections was observed. EZH revealed the absence of the classical mosaic pattern usually found in skeletal muscles. ATPase studies were inconsistent and did not correlate with the expected reciprocal activity of NAD-H diaphorase, particularly on the large fibres. Ultrastructural features consisted of vacuoles within myofilament bundles, "smearing" of Z bands, and "nemaline rods". Occasional myelin figures and lipid-like droplets were observed in subsarcolemmal spaces, associated with scattered clusters of glycogen granules. Abnormal mitochondria and subsarcolemmal inclusions of dense and granular material were conspicuous. "Leptomeric" profiles, "Zebra bodies", or "striated bodies" were noted in 8 EOM's, and an Hirano body was found in 1. The intramuscular nerves contained structures resembling "Luse bodies" in 7 cases. These observations suggest that EOM from individuals with and without strabismus possess unique structural characteristics suggestive of developmental and morphological disarrangement of contractile elements. Some of these changes might play a role in the pathogenesis of strabismus and in the development of clinical symptoms. These features are significantly different from striated skeletal muscle. Therefore the criteria used in the pathological evaluation and diagnosis of skeletal muscle disorders cannot be unequivocally applied to EOM investigations. These data establish the necessity to determine histological norms, ultrastructural patterns, and develop new enzyme histochemistry criteria for the evaluation of EOM. Only then can an acceptable comparison of EOM and skeletal muscle be made.
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PMID:Extraocular muscles: light microscopy and ultrastructural features. 17 43

Female rats were injected subcutaneously with ethionine, and enzymic activities of liver membranes (Na+-k+-stimulated ATPase, Mg2+-stimulated ATPase, glucose-6-phosphatase, NADPH: cytochrome c oxido-reductase and NAD-nucleosidase) examined at proper intervals, during the intraperitoneal treatment of an egg phospholipid preparation (EPL). It is shown that EPL is unable to overcome the enzymic changes due to severe ethionine treatment, but is able to facilitate the recovery times after drug withdrawal for all the enzymic activities, except for NAD-nucleosidase. At lower dosage of the drug, the ethionine treatment is able to prevent the observed change of the glucose-6-phosphatase activity but not that of the Mg2+-ATPase. It is suggested that the EPL treatment may modify the chemical composition ahd/or architecture of liver membranes, altered by the ethionine injection, thus acting, at least partially, on the enzymic changes.
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PMID:The effect of egg phospholipid administration upon liver enzymic activities during ethionine treatment. 18 Dec 70

1. Cells of the hydrogen bacterium Alcaligenes eutrophus are broken by gentle lysis using lysozyme treatment in hypertonic sucrose followed by osmotic shock. By this method, 93% of the in vivo activity of the H2 oxidase is recovered and the ATPase remains particle bound. In contrast, cell disruption in a French pressure cell diminishes the in vivo activity of the H2 oxidase by 50% and solubilizes the bulk of the ATPase. 2. The bacterium contains a periplasmic cytochrome c with bands at 418, 521 and 550 nm (difference spectrum). In addition to cytochrome aa3, b-560, c-553 and o, low temperature difference spectra of membranes show the presence of two further cytochromes (shoulders at 551 and 553 nm). 3. The unsupplemented membrane fraction catalyses the oxidation of hydrogen, NADH, NADPH, succinate, formate and endogenous substrate (NAD linked) at rates 2--3-fold higher than membranes obtained from cells disrupted in a French pressure cell. With the exception of the H2 oxidase all oxidase activities in lysozyme membranes are sensitive to carbonylcyanide m-chlorophenylhydrazone (20-100% stimulation of oxygen uptake). 4. The cytoplasmic fraction contains a B-type cytochrome with absorption maxima at 436 and 560 nm, capable of combining with CO; it contains non-covalently bound protohaem. In alkaline solutions a spectral transition to the haemochrome type with bands at 423, 526 and 556 nm occurs. The addition of NADH to an aerobic suspension of this cytochrome elicits new absorption maxima at 418, 545 and 577 nm (difference spectrum), which are believed to represent an oxygenated form of the reduced cytochrome.
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PMID:Respiratory components and oxidase activities in Alcaligenes eutrophus. 18 46

When photosynthetic membranes from Rhodospirillum rubrum, devoid of loosely bound small molecules and proteins, were passed through a French-pressure cell, the enzyme adenosine-5'-triphosphatase (EC 3.6.1.3.) (ATPase) was released into the soluble fraction. The solubilized ATPase was purified to homogeneity. In many respects it behaved like the enzyme purified by other workers, but it also hydrolyzed Mg-ATP with a small, but significant rate. Furthermore, it was much more stable. Maximal restoration of photophosphorylation in ATPase-depleted membranes was achieved by addition of about 1 mg purified ATPase per mg bacteriochlorophyll. For reconstitution of NAD+-photoreduction, about half of this amount was saturating.
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PMID:Coupling factor adenosine-5'-triphosphatase from Rhodospirillum rubrum: a simple and rapid procedure for its purification. 18 8

The content of coenzyme A-SH (CoASH) and acetyl-CoA of suspensions of rat heart mitochondria was stabilized by the addition of DL-carnitine and acetyl-DL-carnitine, in the presence of the respiratory inhibitor rotenone. The mitochondrial content of NAD+ and NADH was similarly stabilized by the addition of acetoacetate and DL-3-hydroxybutyrate, and the content of ADP and ATP was imposed by the addition of these nucleotides to the mitochondrial suspension, in the presence of uncoupling agent and oligomycin, to inhibit ATPase. Under these conditions, mitochondrial CoASH/acetyl-CoA, NAD+/ NADH, and ADP/ATP ratios could be varied independently, and the effect on the interconversion of active and inactive pyruvate dehydrogenase could be studied. Decreases in both CoASH/acetyl-CoA and NAD+/NADH ratios were shown to be inhibitory to the steady state activity of pyruvate dehydrogenase, and this effect is described at three different ADP/ATP ratios and different concentrations of added MgCl2. A new steady state level of activity was achieved within 10 min of a change in either CoASH/acetyl-CoA or NAD+/NADH ratio; the rate of inactivation was much higher than the rate of reactivation under these conditions. Effects of CoASH/acetyl-CoA and NAD+/NADH may be additive but are still quantitatively lesser than the changes in activity of pyruvate dehydrogenase induced by changes in ADP/ATP ratio. The variation in activity of pyruvate dehydrogenase with ADP/ATP ratio is described in the absence of changes in the other two ratios, conditions which were not met in earlier studies which employed the oxidation of different substrates to generate changes in all three ratios.
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PMID:Studies on the effects of coenzyme A-SH: acetyl coenzyme A, nicotinamide adenine dinucleotide: reduced nicotinamide adenine dinucleotide, and adenosine diphosphate: adenosine triphosphate ratios on the interconversion of active and inactive pyruvate dehydrogenase in isolated rat heart mitochondria. 18 82

Serial transverse sections of porcine longissimus dorsi muscle (18 pigs, 50 to 178 kg live weight) were reacted for NAD tetrazolium reductase and ATPase at pH 9.4, and for glycogen with the periodic acid-Schiff (PAS) reaction. Three histochemical types of muscle fibre were identified; (1) strong ATPase and weak NADH oxidative activity; (2) strong ATPase and intermediate NADH oxidative activity; and (3) weak ATPase and strong NADH oxidative activity. Immediate post mortem samples from one side of each animal were compared with a later post mortem sample from the other side by measuring the absorbance of PAS-stained glycogen at 570 nm with a microscope photometer. Later post mortem absorbance was expressed as a percentage of immediate post mortem absorbance in each category of muscle fibre in order to compensate for distributional error and different starting levels of glycogen. Muscle fibres with weak ATPase and strong NADH oxidative activity showed a progressive decrease in absorbance of PAS-stained glycogen post mortem. In some animals, fibres with strong ATPase and intermediate or weak NADH oxidative activity showed an initial post mortem increase in absorbance of PAS-stained glycogen which was then followed by a progressive decrease. The maximum rates of decrease in absorbance in the three fibre types did not differ to any great extent.
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PMID:Cytophotometry of post mortem glycogenolysis in different histochemical types of muscle fibres of the pig. 19 Jan 93

1. To determine whether controlled (State 4) pyruvate oxidation can support a high energy state, measurements of the redox span NAD-cytochrome c, phosphorylation potential and protonmotive force (the gradient in electrochemical activity of protons across the mitochondrial inner membrane) were made as indices of energy status. For comparison, these three measurements were also made with glycerol 3-phosphate, an alternative substrate. The two substrates gave essentially identical values for the redox span NAD-cytochrome c in State 4, and the phosphorylation potential was of sufficient magnitude to be considered in equilibrium with the redox span over the first two phosphorylation sites. The magnitude of the protonmotive force in State 4 was much less and the implications of this finding are discussed. 2. Measurements made during the controlled (State 4) to active (State 3) transition indicated that with glycerol 3-phosphate as substrate, both the redox span NAD-cytochrome c and the protonmotive force were diminished; the State 4 --> State 3 transition with pyruvate as substrate was accompanied by an increase in the redox span but a decrease in protonmotive force. The contrary behaviour of these two energetic parameters in the presence of pyruvate was ascribed to a transient excess in the flux of protons through the adenosine triphosphatase relative to the protonpumping respiratory chain, in spite of the increased dehydrogenase activity. 3. The lower protonmotive force seen in State 3 relative to State 4 with pyruvate as substrate was due to a diminution of both the electrical (DeltaPsi) and the chemical (DeltapH) components; with glycerol 3-phosphate, the magnitude of the decrease in protonmotive force during the State 4 --> State 3 transition was similar to that seen with pyruvate, but was due to a large decrease in the electrical component (DeltaPsi) and a small rise in the chemical component (DeltapH). The reason for the difference seen in the behaviour of the components of the protonmotive force was investigated but not established. 4. In the presence of oligomycin and ADP, oxidation of pyruvate, but not of glycerol 3-phosphate, supported a greater protonmotive force than in State 4, in keeping with the dehydrogenase activation and increased redox span NAD-cytochrome c found under these conditions. 5. Experiments involving the use of uncoupling agent to stimulate respiration are compared with those in which limiting concentrations of ADP were used. Estimates of the proton conductance of the inner membrane indicate a similar non-linear dependence on uncoupler concentration with the two substrates. 6. A model is proposed as an explanation of the high rates of controlled glycerol 3-phosphate oxidation. The model relies on a high permeability of the inner membrane to protons and other ions being induced by glycerol 3-phosphate oxidation in State 4.
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PMID:The nature of controlled respiration and its relationship to protonmotive force and proton conductance in blowfly flight-muscle mitochondria. 19 84


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