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)

By crossed immunoelectrophoresis with membrane antiserum, 17 antigens have been detected in fractions from plasma membranes of M. lysodeikticus solubilized with Triton X-100. Absorption tests with protoplasts have demonstrated that eight of the antigens are expressed on the surface. Of these antigens the major one has been identified as a succinylated mannan. Five of the principal immunoprecipitates unaffected by absorption with protoplasts were shown by zymograms to possess the following enzymic activites: succinate dehydrogenase (EC 1.3.99.1), ATPase (EC 3.6.1.3), NADH dehyrogenase (EC 1.6.99.3)(two separate components), and malate dehydrogenase (EC 1.1.1.37). These enzymes or enzyme-complexes are, therefore, not expressed on the outer surface of the protoplast membrane.
Proc Natl Acad Sci U S A 1975 Sep
PMID:Antigenic and enzymatic architecture of Micrococcus lysodeikticus membranes established by crossed immunoelectrophoresis. 12 77

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.
Cardiovasc Res 1975 Sep
PMID:Effects of chronic graded ethanol consumption on the metabolism, ultrastructure, and mechanical function of the rat heart. 12 56

Adenosine triphosphatase activity not dependent on sodium or potassium but inhibited by thiocyanate is present in broken-cell homogenates of eel gill and rat kidney. This enzymatic property is predominantly associated with mitochondria, although thiocyanate-inhibited ATPase can also be detected in microsomes with little or no mitochondrial contamination as measured by the activity of the mitochondrial marker enzyme succinic dehydrogenase. When eels are transferred from fresh to salf water, thus increasing active outward transport of chloride across the gill, the thiocyanate-inhibited ATPase of gill microsomes does not change, though the activities of succinic dehydrogenase and Na-K-ATPase in gill homogenates are augmented. The thiocyanate-inhibited ATPase of homogenates of outer renal medulla does not differ from that of renal cortex, in contrast to Na-k-atpase which is higher in renal medulla than in cortex. The data do not support a role for thiocyanate-inhibited ATPase in active chloride transport by epithelial tissues.
Am J Physiol 1975 Sep
PMID:Thiocyanate inhibition of ATPase and its relationship to anion transport. 12 12

The relaxing protein (TM-TN complex) was isolated from plasmodia of Physarum. SDS-gel electrophoresis revealed that the relaxing protein consists of tropomyosin subunits with a molecular weight of 35,000 troponin subunits with molecular weights of 38,000 (T) and 24,000 (I) and several other components. No component corresponding to muscle troponinC (MW-18,000) was detected in the plasmodium relaxing protein. The relaxing protein combined with muscle F-actin, and inhibited the ATPase [EC 3.6.1.3] activity and superprecipitation of reconstituted muscle actomysin in the absence of Ca2+ ions. The inhibition was reversed by adding 1 muM Ca2+ ions.
J Biochem 1975 Sep
PMID:Physarum tropomyosin-troponin complex. Isolation and properties. 13 91

Disrupted cells of Bdellovibrio bacteriovorus exhibited adenosine triphosphatase activity, 60 to 80% of which was in the soluble fraction. Dicyclohexylcarbodiimide did not inhibit the adenosine triphosphatase activity in membrane particles. The particles did not show energy-linked transhydrogenase activity. The activity of non-energy-linked transhydrogenase as well as the rate of oxygen consumption were higher in membrane particles of the host-independent strain than in the host-dependent strains. The uptake of amino acid uptake was inhibited by cyanide and by carbonyl cyanide p-trifluoromethoxyphenyl hydrazone. Valinomycin, in the presence of K+, did not inhibit the uptake, and only partial inhibition was exerted by arsenate and dicyclohexylarbodiimide. Sulfhydryl reagents inhibited amino acid uptake.
J Bacteriol 1976 Sep
PMID:Membrane-associated, energy-linked reactions in Bdellovibrio bacteriovorus. 13 28

Ca2+-adenosine triphosphatase from sarcoplasmic reticulum has been delipidated by gel filtration through a Sephadex G-200 column equilibrated with buffer containing cholate. The delipidated Ca2+-adenosine triphosphatase had negligible adenosine triphosphatase activity, but up to 50% of the ATPase activity was restored when the delipidated enzyme was recombined with phosphilipids. It was shown with the delipidated preparation that the phosphorylation of the enzyme by either ATP or Pi was entirely dependent on phospholipids. Among the purified phospholipids, phosphatidylcholine reactivated the adenosine triphosphatase activity better than phosphatidylethanolamine. Vesicles capable of translocating Ca2+ were reconstituted from delipidated Ca2+-adenosine triphosphatase and phosphatidylethanolamine, but not with phosphatidylcholine alone. We conclude that the firmly bound phospholipids which are purified together with the adenosine triphosphatase protein are not essential for the pump since they can be substituted by phosphatidylethanolamine isolated from soybeans.
J Biol Chem 1976 Sep 10
PMID:Phospholipid-protein interactions in the Ca2+-adenosine triphosphatase of sarcoplasmic reticulum. 13 36

Exchange of sarcoplasmic reticulum phospholipids with dipalmitoyllecithin inhibits the (Mg2+ + Ca2+)-activated ATPase activity below 40 degrees by inhibition of the decomposition of phosphoprotein intermediate. The rate of phosphoprotein formation and the steady state concentration of phosphoprotein measured by rapid kinetic techniques are affected to a lesser extent. The inhibitory effect of dipalmitoyllecithin on ATPase activity is probably related to the viscosity of the hydrocarbon region of the membrane which inhibits the conformational change leading to calcium translocation and the eventual cleavage of phosphoprotein.
J Biol Chem 1976 Sep 10
PMID:Mechanism of ATP hydrolysis by sarcoplasmic reticulum and the role of phospholipids. 13 38

Heavy meromyosin treated with the ATP analog, 6,6'-dithiobis(inosinyl-5'-yl imidodiphosphate), (slppNHp)2, in the presence of adenyl-5'-yl imidodiphosphate at 0 degrees loses its EDTA-ATPase activity and actin binding ability in a parallel manner. Studies with myosin show that under the above conditions (slppNHp)2 reacts preferentially with the single cysteines of the alkali light chains (Mr = 20,700 and 16,500) suggesting a role for these subunits in regulating actin-myosin interaction and ATP cleavage.
J Biol Chem 1976 Sep 10
PMID:Modification of the alkali light chains of skeletal myosin inhibits actin binding and adenosine triphosphate cleavage. 13 39

Differential ultracentrifugation of an extract of the plasmodium of Physarum polycephalum yields a high-speed fraction which exhibits calcium-sensitive adenosine triphosphate activity at low ionic strength. The rate of inorganic phosphate production increased from 2- to 25-fold in different preparations when the calcium concentration was increased from about 10(-8) to 10(-5) M. Complement fixation using specific antibody to Physarum myosin showed the fraction to contain 3% myosin. By electron microscopy, actin-like microfilaments 50--150 nm long were present. Addition of pure rabbit F-actin or myosin to this fraction activated the ATPase measured in EGTA and so partially reversed the calcium sensitivity. If muscle myosin was added to the supernatant from which the fraction was centrifuged, a "hybrid complex" was obtained which included actin and additional protein from the plasmodium, and this hybrid was also calcium sensitive. Over 85% of the calcium-sensitive, magnesium-activated ATPase could be precipitated by sequential "hybrid" formation. The calcium sensitivity of the hybrid was maximal when formed at the lowest ratios of added myosin to Physarum proteins. It is concluded that the results do not allow a simple interpretation along the lines of either actin-linked or myosin-linked sensitivity. Evidence consistent with both a form of actin-linked and myosin-linked sensitivity is present in our results.
Biochemistry 1976 Sep 21
PMID:A calcium-sensitive preparation from Physarum polycephalum. 13 44

Na+-dependent ADP/ATP exchange activity, of a (Na++K+)-dependent ATPase preparation from eel electric organ, was measured in terms of the incorporation of 14C into ATP during incubations with labeled ATP and [14C]ADP. Estimates of initial rates of exchange were possible by keeping changes in nucleotide concentrations, from both exchange and extraneous hydrolytic processes, to less than 10%. Under these conditions, increases in MgC12 concentration, from 0.2 to 3 mM, generally inhibited this exchange activity. The concentrations of free Mg2+, Mg-ATP, and Mg-adp present, with a range of MgC12, ATP, and ADP concentrations, were calculated from measured dissociation constants. Inhibition was associated with Mg-ATP as well as with Mg2+, at concentrations from 0.4 to 1 mM (Mg-ADP, in the same concentration range, probably inhibited also). The affinity of the enzyme for these inhibitors is in fair correspondence with demonstrated affinties for Mg2+, Mg-atp, and Mg-ADP at low affinity substrate sites, measured kinetically. These observations are considered in terms of a dimeric enzyme with high and low affinity substrates sites: ADP/ATP exchange being catalyzed at the high affinity sites, with inhibition occurring through occupancy by Mg2+, Mg-ATP, or Mg-ADP, of the low affinity sites, thereby pulling the reaction process away from those steps involved in exchange.
Biochim Biophys Acta 1976 Sep 13
PMID:The (Na + K+)-dependent ATPase. Mode of inhibition of ADP/ATP exchange activity by MgC12. 13 46


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