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)

Adenosine triphosphatase enzymatic activity was investigated in human approximatively normal, dysplastic and neoplastic mammary tissue, by three different methods. Staining intensity varied within wide limits; myoepithelial cells and blood vessels showed similar enzymatic activity. Epithelial cells reacted only faintly, or not at all; carcinoma cells were never labelled. Stromal response was highly variable. The calcium-cobalt method of Padykula and Herman gave more intense reactions than the lead-nitrate procedure of Wachstein and Meisel, either in the original form or according to the modifications recommended by Russo and Wells. With the latter method the sharpness of stain deposits on the different structures was markedly enhanced. The functional significance of ATPase activity is discussed.
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PMID:ATPase activity in the breast: a comparison between three methods. 9 Dec 95

Since the first observation by Spann et al., it has become clear that in cardiac hypertrophy induced by a mechanical overloading, the velocity of shortening of the cardiac muscle (Vmax) is reduced (see ref. 2 for review). Most authors agree that this mechanical alteration is accompanied by a decrease in the Ca2+-dependent ATPase activity of myosin (see ref. 3 for review). The molecular basis of such changes was unknown because the structural modifications of the myosin molecule were ill-defined. Nevertheless, it has recently been shown that, like skeletal muscle myosin, cardiac myosin is composed of several polymorphic forms, comparable to isoenzymes. In the skeletal muscle, new functional requirements can induce changes in both contractile activity and type of myosin isoenzyme synthesised. We now report that an increase in cardiac work produced by mechanical overloading in rats induces the preferential synthesis of a cardiac myosin isoenzyme characterised by specific immunological and electrophoretic properties and exhibiting a lower ATPase activity. This adaptive change could account for the reduced shortening speed of this hypertrophied cardiac muscle.
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PMID:Myosin isoenzyme redistribution in chronic heart overload. 9 73

Embryonal rhabdomyosarcomas from the nasopharynx of two children were examined by histochemical methods commonly applied to muscle biopsies. These stains included nicotinamide adenine dinucleotide-tetrazolium reductase (NADH-TR), succinate dehydrogenase (SDH), PAS, PAS-diastase, myophosphorylase, calcium-mediated adenosine triphosphatase (ATPase) preincubated at high and low pH, and oil red O. Myofibrils were easily identified with ATPase and blood vessel walls were also stained. NADH-TR clearly showed longitudinal and cross-striations that were not seen with H&E or PTAH stains. The modified Gomori trichrome stain additionally contributed to the recognition of myofibrils. Some techniques of muscle histochemistry applied to fresh frozen sections of tumor tissue may provide evidence of muscular differentiation in otherwise poorly differentiated sarcomas for a more accurate diagnosis of rhabdomyosarcoma.
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PMID:Diagnostic value of histochemistry in embryonal rhabdomyosarcoma. 9 52

1 mg/kg L-thyroxine was administered to rats for 14 days to evaluate the potential of the hyperthyroid state to induce heart hypertrophy and its effect on myosin adenosine-triphosphatase (ATPase) activity. Evidence of hyperthyroidism such as weight loss, elevation of rectal temperature, increased heart rate and oxygen consumption, was observed in all treated rats. Cardiac enlargement was determined by comparison of wet and dry ventricle weights, myocardial RNA, DNA and protein content. Wet and dry ventricle weights and the level of cardiac RNA and protein were augmented by thyroxine treatment. ATPase activity of cardiac myosin was stimulated as the Ca2+ concentration in the incubation medium increased. No difference was found in Ca2+-activation, salt sensitivity or ATPase activity of unreacted and sulphydrylmodified cardiac myosins from euthyroid or hyperthyroid groups. The results showed that in hyperthyroid rats, in contrast to some other species, the biochemical mechanism responsible for the enhancement of cardiac contractility is not an increased myosin ATPase.
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PMID:Thyroxine-induced cardiomegaly: assessment of nucleic acid, protein content and myosin ATPase of rat heart. 9 43

The effects of Ca2+ on the RNA polymerase activity of the nuclei isolated from normal and denervated gastrocnemius muscles of the rabbit were studied. It was shown that 18 hrs after denervation the RNA synthesis in vitro, Ca2+ content and the Ca, Mg-ATPase activity of the nuclei are decreased. After addition of exogenous Ca2+ the incorporation of labelled UTP into the nuclei is stimulated in the denervated muscle and is inhibited in the control. Electrostimulation of the denervated muscle at the peripheral part of the sciatic nerve for 3 hrs increases both the RNA synthesis in the nuclei and the Ca2+ content, as well as the Ca, Mg-ATPase activity. Exogenous Ca2+ has an inhibitory effect on the nuclei of the stimulated muscle. The correlation established is indicative of participation of Ca2+ in the transmission of excitation in skeletal muscle sarcolemma to the processes occurring in nuclear structures.
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PMID:[Role of calcium in realization of nervous control during RNA synthesis in skeletal muscles]. 9 40

It has been shown that the activity of Ca(2+)-ATPase increases during development. Epinephrine in vivo increases the activity of Ca(2+)-ATPase in chick skeletal muscles. The effect of hormone is lacking at embryonic stages of development and appears only before hatching. In the presence of exogenous protein kinase, cAMP also increases the activity of the enzyme, this effect being observed also in embryonic muscles. Lack of effect of epinephrine on Ca(2+)-ATPase in embryonic muscles is associated with non-reactivity of their adenylate cyclase to catecholamines. Ca(2+)-ATPase itself already at embryonic period is ready to react to cAMP. It is concluded that Ca(2+)-ATPase of sarcoplasmic reticulum is one of the sites of action of catecholamines on calcium metabolism in muscle cell and that this action is realized via the system adenylate cyclase-cAMP-protein kinase.
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PMID:[The effect of catecholamines on the Ca2(+)-adenosinetriphosphatase of the sarcoplasmic reticulum in the skeletal muscles in chicken ontogeny]. 9 34

Ca2+ accumulation and endogenous respiration of sporulating Bacillus megaterium are inhibited to the same extent by electron-transport of inhibitors and the uncoupler carbonyl cyanide p-trifluoromethoxyphenylhydrazone, suggesting that Ca2+ is accumulated by an active transport process. Forespores isolated in stage V of sporulation demonstrated Ca2+-specific carrier-mediated Ca2+ uptake, consistent with downhill transfer [Hogarth & Ellar (1978) Biochem. J. 176, 197-203]. In the present studies forespore Ca2+ uptake was unaffected by carbonyl cyanide p-trifluoromethoxyphenylhydrazone and by concentrations of respiratory inhibitor that inhibited forespore endogenous respiration by 85%. These data suggest that Ca2+ enters the isolated forespore by facilitated diffusion. Ca2+ uptake into sporulating protoplasts was completely inhibited by concentrations of respiratory inhibitors that had no effect on either Ca2+ uptake or respiration of stage-V forespores, but which resulted in inhibition of mother-cell membrane NADH oxidase. These results indicate that the mother-cell membrane is a site for active transport of Ca2+ into the sporulating cell. The effects of the adenosine triphosphatase inhibitor dicyclohexylcarbodi-imide on mother-cell membrane adenosine triphosphatase, NADH oxidase and protoplast Ca2+ uptake were examined.
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PMID:Energy-dependence of calcium accumulation during sporulation of Bacillus megaterium KM. 11 Mar 19

As part of a study on the evolutionary aspects of control mechanisms, a number of structural muscle components from the Pacific dogfish (Squalus acanthias) are described. These include troponin, tropomyosin, actin, and myosin. Troponin (mol wt 108.000) was resolved into its constitutive subunits, repeated by a 20,500 mol wt fragment which binds 2 mol of Ca2+/mol with a KDiss of 0.91 mum, and an inhibitory component of 30,000 and a 58,000 component which are necessary for the calcium sensitivity of actomyosin ATPase. Tropomyosin and actin share many properties with their counterparts from higher vertebrates. Proteins similar to parvalbumins, i.e., the low molecular weight calcium-binding proteins widely distributed in fish, amphibians, and mammalian muscle, could be generated from troponin and its calcium-binding subunit by limited proteolysis. The appearance of immunological cross-reactivity and other similar features suggested some identity, but differences in the amino acid analysis exclude the possiblity that parvalbumins occur as breakdown products of troponin. The close relationship between parvalbumins and the calcium-binding subunit brings additional evidence that these proteins have arisen through divergent evolution.
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PMID:Structural proteins of dogfish skeletal muscle. 12 58

A plasma membrane preparation purified from guinea pig ventricles without the use of high concentrations of detergents or structure-disrupting salts was used to compare the mechanisms of controlling sodium, potassium-activated adenosinetriphosphatase (Na, K-ATPase) and adenylate cyclase activities. The basal ATPase activity of 4-6 mu moles P1/hour mg-1 protein, measured in 120 mM NaC1 or KC1, was approximately doubled in 100 mM NaC1 plus 20 mM KC1. This increment, the Na, K-ATPase, was abolished by 10-5M ouabain, the K1 for ouabain being approximately 3 X 10-7M. 1-Epinephrine had no effect on Na, K-ATPase, but NaF was inhibitory. Adenylate cyclase, which had a basal activity of approximately 50% by NaC1 or KC1 alone at concentrations up to 0.2M. There was no additional stimulation of adenylate cyclase activity when na+ K+ included together. Both 1-epinephrine and NaF cause significant stimulation of adenylate cyclase, but neither basal nor activated cyclic AMP PRODUCTION WAS INFLUENCED BY OUABAIN. Half-maximal stimulation was seen at approximately 5 X 10-6M 1-epinephrine. Both the catecholamine and NaF increased the V-max ofcardiac plasma membrane adenylate cyclase without significantly influencing Km. Increasing Ca2+ in the range between 10-7 and 10-3M inhibited basal, 1-epinephrine-stimulated, and NaF-stimulated activities. Basal rates of cyclic AMP production were more sensitive to Ca2+ than was 1-epinephrine stimulation was increased from approximately 60% in 0.5 mM EGTA to approximately 150% in 10-7M Ca2+ and 400% in 10-5M Ca2+. The inhibitory effect of Ca2+ on adenylate cyclase activity may represent a negative feed back mechanism by which elevation of intracellular Ca2+ concentration lowers cellular levels of cyclic AMP and thus reduces Ca2+ influx into the myocardium.
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PMID:Control of cardiac sarcolemmal adenylate cyclase and sodium, potassium-activated adenosinetriphosphatase activities. 12 80

Myosin A and actomyosin were isolated from the skeletal muscle of old and young rats. The velocity of the Ca2+ activated myosin A ATPase was increased in the case of the older animals. On the other hand the velocity of the Mg-2plus activated actomyosin ATPase was decreased in the skeletal muscle of the aging rats. At 5 X 10-5M EGTA concentration the inhibition of the Mg-2plus activated myosin B ATPase of the 1-month-old rats was two- to threefold smaller than that of the older animals. It was shown that the myosin A component of the actomyosin was responsible for the decreased troponin inhibition in the case of the 1-month-old rats. Between the ages of 1 month and 29 months the number of free myosin A SH groups decreases by 50%. The lipid peroxidation in the muscle of the 1-month-old animals.
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PMID:Enzymatic studies on the skeletal myosin A and actomyosin of aging rats. 12 7


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