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)

Infection of Escherichia coli with bacteriophage T7 results in an inhibition of the host exonuclease V (recB, C DNase) activity. This inhibition is not observed when cells are infected in the presence of chloramphenicol or with a gene 1 mutant. The protein responsible for the inhibition of exonuclease V has been partially purified from T7-infected cells. The protein which does not possess nuclease or ATPase activity can inhibit all nucleolytic activities associated with exonuclease V. The protein does not, however, inhibit the DNA-dependent ATPase activity associated with exonuclease V. The inhibitory protein has a molecular weight of about 12,000, as determined from sedimentation analysis in glycerol gradients.
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PMID:Partial purification and properties of a bacteriophage T7 inhibitor of the host exonuclease V activity. 12 51

Three sequential sets of ethanolic rats (E) and their matched controls (C) were fed regular chow containing standard vitamins with the ethanol group in each series also receiving a progressively greater alcohol intake for 3 to 6 months: E1 5%, E2 10%, and E3 25% ethanol. Electron microscopy showed swelling of mitochondria, transverse tubules and sarcoplasmic reticulum, dehiscence of intercalated discs and disintegration of myofibrils scattered throughout the ventricular myocardium in E1 and E2 as early as 7 wk after beginning 5% ethanol; in addition, there were clumping of mitochondria and supercontraction of myofibrils in E3. Concomitant with substructural abnormalities in E3, there were slight but significant depressions of cardiac myofibrillar ATPase activity and mitochondrial function. Cardiac catecholamines, hydroxyproline, and total bound glycerol were unchanged. Alteration of isometric contraction of isolated, supported left ventricular papillary muscles occurred initially in E2 and was clearly evident in E3 by significant reduction of duration of systolic active state (time from onset to peak tension), while total tension generated and peak rate of tension rise were not yet disturbed. Extra vitamin supplementation in additional rats drinking 25% ethanol minimally lessened decline in myofibrillar ATPase activity, but otherwise provided no protection. Thus, chronic daily ingestion of graded quantities of ethanol representing 10 to 30% of total calories in well-nourished animals exerted toxic effects on microstructure, metabolism and mechanics of the ventricle. These alterations are postulated to be pertinent to early pathogenesis of clinical alcoholic cardiomyopathy.
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PMID:Effects of chronic graded ethanol consumption on the metabolism, ultrastructure, and mechanical function of the rat heart. 12 56

A particulate subcellular fraction from Escherichia coli K-12 induced in anaerobic sn-glycerol 3-phosphate (G3P) dehydrogenase and fumarate reductase can catalyze under anaerobic conditions the transfer of hydrogens from G3P to fumarate, with attendant generation of high-energy phosphate. The phsophorylation process is more sensitive than the transhydrogenation process to inhibition by the detergent Triton X-100. The same is true with respect to sensitivity to sodium azide, carbonyl cyanide m-chlorophenylhydrazone and N,N'-dicyclohexylcarbodiimide. Such a preparation derived from cells with beta-galactoside permease can accumulate thiomethyl beta-D-galactoside anaerobically, and the accumulation can be stimulated twofold by adding G3P and fumarate. Mutants lacking the membrane-associated Mg2+-dependent adenosine triphosphatase cannot grow anaerobically on glycerol with fumarate as the hydrogen acceptor, although they can grow aerobically on glycerol alone.
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PMID:Anaerobic energy-yielding reaction associated with transhydrogenation from glycerol 3-phosphate to fumarate by an Escherichia coli system. 12 85

4-Methylazidebenzene and various azidebenzene derivatives were prepared, and the effects of these compounds on oxidase activities and active transport reactions for amino acids in Escherichia coli cells were studied. Azidebenzenes inhibited succinate oxidation by intact cells preferentially to glycerol oxidation. However, the azidebenzenes could not inhibit succinate oxidation which was not coupled to phosphorylation. The compounds inhibited succinate driven proline uptake much more strongly than isoleucine uptake. Unlike sodium azide and diphenyl phosphorazidate, azidebenzenes did not inhibit membrane-bound, Mg2+-requiring ATPase [EC 3.6.1.3] of E. coli. Reactivities of various azide compounds in the mechanism of inhibition for energy transducing and energy transforming reactions were discussed briefly.
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PMID:Transport of sugars and amino acids in bacteria. XIV. Preferential inhibition of oxidase activities and active transport reactions for amino acids by azidebenzenes. 12 88

'Immobile' (im) is a recessive lethal mutation discovered in the F3 of a Xenopus (Xenopus laevis laevis) originating from a mesodermal nucleus of a neurula transplanted into an enucleated egg. The im embryos do not contract after mechanical stimulation nor do they present any spontaneous contraction from the neurula stage onwards. Development proceeds normally during the first days after which deformation of the lower jaw and tail are observed. The im tadpoles die when normal controls are at the feeding stage. Nevous and muscular tissues are histologically normal in the mutant tadpoles; at advanced stages, however, an irregularity in the path of the myofibrils is observed which is especially conspicuous in the electron microscope. Cholinesterases and ATPase are present in the mutant muscles. Parabiosis and chimerae experiments have shown that parabionts and grafts behave according to their own genotype. Cultures of presumptive axial systems with or without ectoderm lead to the conclusion that, first of all, the abnormality is situated in the mesodermal cells and secondly that the first muscular contractions in normal Xenopus laevis are of myogenic origin. The banding pattern of the myofibrils is normal as was shown by obtaining contractions of glycerol extracted in myoblasts with ATP. It seems therefore that in this mutation, the abnormality is situated in the membraneous system of the muscular cell, sarcoplasmic reticulum and/or tubular system as is probably the case in the mdg mutation of the mouse.
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PMID:'Immobile' (im), a recessive lethal mutation of Xenopus laevis tadpoles. 12 24

Growth of Halobacterium halobium under illumination with limiting aeration induces bacteriorhodopsin formation and renders the cells capable of photophosphorylation. Cells depleted of endogenous reserves by a starvation treatment were used to investigate the means by which energy is coupled to the active transport of [14C]proline, -leucine, and -histidine. Proline was readily accumulated by irradiated cells under anaerobiosis even when the photophosphorylation was abolished by the adenosine triphosphatase inhibitor N,N'-dicyclohexylcarbodimiide (DCCD). The uptake of proline in the dark was limited except when the cells were allowed to accumulate adenosine 5'-triphosphate (ATP) by prior light exposure or by the oxidation of glycerol. DCCD inhibited this dark uptake. These findings essentially support Mitchell's chemiosmotic theory of active transport. The driving force is apparently the proton-motive force developed when protons are extruded from irradiated bacteriorhodopsin or by the dydrolysis of ATP by membrane adenosine triphosphatase. Carbonylcyanide m-chlorophenylhydrazone (CCCP), a proton permeant known to abolish membrane potential, was a strong inhibitor of proline uptake. Leucine transport was also apparently driven by proton-motive force, although its kinetic properties differed from the proline system. Histidine transport is apparently not a chemiosmotic system. Dark- or light-exposed cells show comparable initial rats of histidine uptake, and these processes were only partially inhibited by DCCD or CCCP. The histidine system apparently does not utilize ATP per se since comparable rates of uptake were exhibited by cells of differing intracellular ATP levels. Irradiated cells did effect a greater total accumulation of histidine than dark-exposed cells. These findings suggest that ATP is needed for sustained transport.
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PMID:Energy coupling in the active transport of amino acids by bacteriohodopsin-containing cells of Halobacterium holobium. 12 52

Tightly bound adenine nucleotides are removed from multiple binding sites on beef heart mitochondrial ATPase (F1) by chromatography on columns of Sephadex equilibrated with 50% glycerol. Release of nucleotides from the enzyme is associated with large decreases in sedimentation velocity (from 11.9 S to 8.4 S) which may be observed in concentrated solutions of polyols. Polyol-induced conformational changes are reversed when the enzyme is returned to dilute buffers. The nucleotide-depleted enzyme restores oxidative phosphorylation in F1-deficient submitochondrial particles. Reconstitution of nucleotide-depleted F1 with the ATP analog (adenylyl-imidodiphosphate (AMP-PNP), almost 5 moles of AMP-PNP per mole of enzyme, results in preparations with substantially inhibited ATPase activity which nevertheless restores oxidative phosphorylation and the 32Pi-ATP exchange reaction in F1-deficient submitochondrial particles. Incubation of the analog-labeled enzyme with ATP and Mg++ results in partial displacement of the analog and a time-dependent recovery of ATPase activity.
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PMID:Physical and enzymatic properties of nucleotide-depleted beef heart mitochondrial adenosine triphosphatase. 12 61

The uptake of proline and glutamine by cytochrome-deficient cells of Escherichia coli SASX76 grown aerobically on glucose or anaerobically on pyruvate was stimulated by these two substrates. Pyruvate could not stimulate transport in the glucose-grown cells. Uptake of these amino acids energized by glucose was inhibited by inhibitors of the Ca2+, Mg2+-stimulated ATPase such as DCCD, pyrophosphate, and azide, and by the uncouplers CCCP and 2,4-dinitrophenol. Glycerol (or glycerol 3-phosphate) in the presence of fumarate stimulated the transport of proline and glutamine under anaerobic conditions in cytochrome-deficient cells but not in membrane vesicles prepared from these cells although glycerol 3-phosphate-fumarate oxidoreductase activity could be demonstrated in the vesicle preparation. In contrast, in vesicles prepared from cytochrome-containing cells of E. coli SASX76 amino acid transport was energized under anaerobic conditions by this system. Inhibitors of the Ca2+, Mg2+-activated ATPase and uncoupling agents inhibited the uptake of proline and glutamine in cytochrome-deficient cells dependent on the glycerol-fumarate oxidoreductase system. Ferricyanide could replace fumarate as an electron acceptor to permit transport of phenylalanine in cytochrome-deficient or cytochrome-containing cells under anaerobic conditions. It is concluded that in cytochrome-deficient cells using glucose, pyruvate, or glycerol in the presence of fumarate, transport of both proline and glutamine under under anaerobic conditions is energized by ATP through the Ca2+, Mg2+-activated ATPase. In cytochrome-containing cells under anaerobic conditions electron transfer between glycerol and fumarate can also drive transport of these amino acids.
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PMID:Anaerobic transport of amino acids coupled to the glycerol-3-phosphate-fumarate oxidoreductase system in a cytochrome-deficient mutant of Escherichia coli. 13 Sep 24

The effect of dantrolene sodium, 1-(5-(p-nitrophenyl)furfuryli-deneamino)hydantoin sodium hydrate, on electrical and mechanical response in frog skeltal muscles (whole muscles or single fibers) and on the biochemical properties of contractile proteins and fragmented sarcoplasmic reticulum isolated from frog or rabbit skeletal muscle was investigated. The peak tensions of twitch, tetanus and potassium contracture were significantly inhibited by dantrolene, without affecting the magnitude of resting potential, the amplitude and duration of action potential and the negative afterpotential. On the other hand, ATP-INDUCED SHORTENING OF GLYCEROL-EXTRACTED RABBIT PSOAS MUSCLE FIBERS, ATPase activity of frog myofibrils and Ca release induced by caffeine, Ca uptake and ATPase activity of fragmented sarcoplasmic reticulum of frog or rabbit muscle were not affected by dantrolene. Caffeine contracture was partially inhibited by dantrolene and was almost unchanged by it in potassium-depolarized muscele fiber. Nitrate ions and low concentration of caffeine rapidly recovered the twitch inhibition induced by dantrolene. These results suggested that dantrolene acts on the membrane of transverse tubules and possibly the triadic junction and that it inhibits the inward movement of Ca and subsequently decreases the release of activator Ca from sarcoplasmic reticulum.
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PMID:Effect of dantrolene sodium on excitation-contraction coupling in frog skeletal muscle. 13 70

The Arrhenius plots for the membrane-bound ATPase and its soluble form purified from Micrococcus lysodeikticus, presented discontinuities near 30 degrees C at pH 7.5. Glycerol-containing lipids were not responsible for these discontinuities. The values of the enthalpies of activation were 12 (soluble) and 22 (membrane-bound) kcal/mol (50.2 and 92.0 kJ/mol) above 30 degrees C and 42 (soluble) and 29 (membrane-bound) kcal/mol (175.7 and 121.3 kJ/mol) below that temperature. The results suggested that both molecular forms of the ATPase were able to adopt at least two different structures, above and below the critical temperature. Of the two, only the high-temperature structure seemed to be enzymically active. In the case of lipid-dependent ATPases, such as the Escherichia coli enzyme, the transition between both enzyme structures probably occurred with simultaneous "melting" of their lipid microenvironment.
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PMID:Activation parameters of the adenosine triphosphatase of Micrococcus lysodeikticus. A comparison of the soluble and membrane-bound forms of the enzyme. 13 1


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