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)

The cytochemical localization and intensity of adenosine triphosphatase (ATPase) activity in the spermatozoa from fertile and infertile human ejaculate were observed by an electron microscope. Sperm from fertile and infertile human ejaculate were fixed in 1% glutaraldehyde and treated histochemically to demonstrate calcium- and magnesium-dependent ATPase (Ca++- and Mg++-dependent). Furthermore, as substrates, ADP, AMP, and beta-glycerophosphate were used. The localization of Ca++-activated ATPase was not different from that of Mg++-activated ATPase. In the fertile human ejaculated sperm, ATPase activity was found on the surface of the acrosome and mitochondria consisting of the mitochondrial sheath, around the outer coarse fibers and in the axial filament complex. Compared with the result with fertile specimens, in the infertile human ejaculated sperm, ATPase activity on the motile structures, the outer coarse fibers, and the axial filament complex were considerably weaker and occasionally not recognized. From this study, it may be considered that ATPase around the outer coarse fibers and in the axial filament complex of sperm may serve to mediate contraction of the axonemal elements during motility. (Author's Modified)
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PMID:[The cytochemical localization of ATPase activity in the spermatozoa from fertile and infertile human ejaculate by electron microscope (author's transl)]. 13 69

The ATPase activity of actomyosin prepared from taenia coli muscle of guinea pig was found to increase upon adding rabbit skeletal heavy meromyosin (HMM) in the absence of Ca2+. SDS-gel electrophoresis of muscle homogenates did not reveal the presence of troponin. Ca2+-regulation in taenia coli muscle thus appears to be myosin-linked. The glycerinated muscles which did not develop any tension in the presence of EGTA contracted after irrigation with rabbit skeletal myosin. Skeletal HMM could also cause tension generation in strips of glycerinated taenia coli in the presence of EGTA. The tension developed by the muscles in the presence of Ca2+ was increased if HMM was added. The HMM-induced tension was associated with a marked increase in ATPase activity both in the presence and in the absence of Ca2+. No HMM-associated tension could be detected when inactivated HMM was employed or when MgATP was substituted with Mg-pyrophosphate or Mg-AMP-PNP. The mechanical effect of HMM probably results from a mechanochemical interaction between the added HMM and muscle actin.
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PMID:Evidence for myosin-linked regulation in guinea pig taenia coli muscle. 13 41

1. When rat spleen mitochondria are incubated with oxidizable substrates, added MgCl2 (greater than 150 muM free concentration) markedly stimulates state-4 respiration and lowers both the respiratory control and ADP/O ratios; this effect is reversible on addition of excess of EDTA. 2. With [gamma-32P]ATP as substrate, an Mg2+-stimulated ATPase (adenosine triphosphate) was identified in the atractyloside-insensitive and EDTA-accessible space of intact rat spleen mitochondria. 3. Oligomycin has no effect on the activity of the Mg2+-stimulated ATPase at a concentration (2.0mug/mg of protein) that completely inhibits the atractyloside-sensitive reaction. Of the two ATPase activities, only the atracytoloside sensitive reaction is stimulated (approx. 40%) by dinitrophenol. 4. On digitonin fractionation the atractyloside-insensitive Mg2+-stimulated ATPase co-purifies with the outer membrane-fraction of rat spleen mitochondria, whereas (as expected) the atractylosidesensitive activity co-purifies with the inner-membrane plus matrix fraction. 5. Stoicheiometric amounts of ADP and Pi are produced as the end products of ATP hydrolysis by purified outer-membrane fragments; no significant AMP production is detected during the time-course of the reaction. 6. The outer-membrane ATPase is present in rat kidney cortex and heart mitochondria as well as in spleen, but is absent from rat liver, thymus, brain, lung, diaphragm and skeletal muscle.
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PMID:Location of an oligomycin-insensitive and magnesium ion-stimulated adenosine triphosphatase in rat spleen mitochondria. 13 23

Administration of 60,000 i.e. of vitamin A into rats within three weeks caused an increase in amount of reticulocytes, in the rate of glucose utilization and in formation of lactic acid by erythrocytes. The activity of glycolytic enzymes was intensified. The activity of hexokinase was increased by 84.6%, activities of aldolase and phosphohexoisomerase were increased by 34%. But in the erythrocytes content of AMP, ADP and ATP was unaltered, probably due to activation of total and Na+, K+-dependent ATPase. The harmful effect of an excess of the vitamin A was manifested in an increased content of Na+ in erythrocytes and also in decreased stability of the cells to acid hemolytics.
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PMID:[Intensity of glycolysis and energy metabolism in erythrocytes in experimental hypervitaminosis A]. 13 57

An approach to explain the early metabolic disturbances induced by a moderate ischaemia on the basis of comparative biochemical investigations concerning the oxidative metabolism in the skeletal muscles, is the object of the present paper. These investigations have revealed the following findings: (i) during a slight ischaemia the skeletal muscle maintains its ability to oxidize in vitro lactate and exhibits an increased activity in oxidizing pyruvate, succinate and L-glutamate, and (ii) the stores of adenosine and ATP are depleted and an important accumulation of inorganic phosphate, accompanied by a remarkable activation of phosphatases, occurs in the ischaemic muscle, while no significant changes in the ATPase and creatine phosphokinase activities and in the amount of AMP, ADP and creatine phosphate are detectable in this muscle.
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PMID:Early biochemical disorders in hindlimb muscles following femoral artery stenosis in dogs: oxidative metabolism. 13 90

Bovine cardiac myosin ATPase activity was rapidly inactivated by the purine disulfide analog of ATP,6,6'-dithiobis(inosinyl imidodiphosphate). Kinetic investigations showed that this analog acted as a site-specific reagent at 0 degrees with a Ki of 130 muM and a half-life of 8.2 min at saturating inhibitor concentrations. Concentrations (50 to 500 muM) of ATP, adenyl-5'-yl imidodiphosphate (AMP-PNP), or ADP that saturated the active site caused an enhancement in the rate of inactivation, indicating the purine disulfide analog was not reacting at the active site. Under these conditions saturation kinetic data were still observed with Ki values remaining unchanged (120 muM) but with the half-life of inactivation decreasing to 6.0 min (ATP) and 4.6 min (AMP-PNP) at saturating inhibitor concentrations. At concentrations greater than 0.5 mM ATP, AMP-PNP, or ADP there was a decrease in the rate of inactivation, implying protection by these nucleotides. However, saturation kinetics of inactivation could no longer be demonstrated, implying a change in the mechanism of inactivation. A comparison of the inactivation of the Mg2+, Ca2+, and EDTA-ATPase activities of cardiac myosin after modification by the purine disulfide analog showed that the Mg2+- and Ca2+ATPase activities plateaued at approximately 60% and 40%, respectively, while the EDTA-ATPase activity continued to decrease to below 10%. This evidence supports the suggestion that the purine disulfide analog was not reacting at the active site. Equilibrium dialysis experiments were used to measure the binding of [8-3H]AMP-PNP to native cardiac myosin, the thiopurine nucleotide-modified myosin, and the derivative formed by displacing the thiopurine nucleotide by cyanide (thiocyanato-myosin). Native myosin bound a total of 2.1 mol of AMP-PNP with a binding constant of 6.0 X 10(6) M-1. There was a 15 to 40% decrease in the number of AMP-PNP binding sites in the enzyme derivatives, but the active sites appeared not to be blocked since the association constants remained essentially unchanged (KA=3.9 X 10(6) M-1 for thiopurine nucleotide-myosin and 12.0 X 10(6) M-1 for thiocyanato-myosin). The kinetic studies and the binding experiments indicate that the purine disulfide analog reacts at a specific site other than the active site but do not offer support to earlier suggestions from skeletal myosin studies that this site is a possible ATP control site.
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PMID:Reaction of cardiac myosin with a purine disulfide analog of adenosine triphosphate. I. Kinetics of inactivation and binding of adenylyl imidodiphosphate. 13 83

The UV absorption difference spectrum of heavy meromyosin induced by adenylyl imidodiphosphate (AMP-PNP) was found to be changed by temperature. At higher temperatures, the shape of the difference spectrum resembled the ATP-form of difference spectrum induced by ATP. At lower temperatures, a different shape was observed, resembling that induced by ADP. This temperature transition was found in the presence of both MgCl2 and MnCl2. The transition temperatures, were 21 degrees and 9 degrees in the presence of MnCl2 and MgCl2, respectively. A similar temperature dependence was observed with the difference spectrum induced by ATP at the steady state. The transition temperatures in this case were 11 degrees and 4.5 degrees in the presence of MnCl2 and MgCl2, respectively. The similarity of the effects of the two kinds of divalent cation on both transitions indicates that the temperature induced transition between two species of heavy meromyosin-AMP-PNP complex mimics the step in APTase [EC 3.6.1.3] reaction in which the intermediate complex showing the ATP-form of difference spectrum changes to that showing the ADP-form. The equilibrium constant of the decay step of the ATP-form of difference spectrum to the ADP-form in ATPase is, therefore, thought to be highly temperature dependent. Thermodynamic parameters were calculated for the transition between the two species of heavy meromyosin AMP-PNP complex. Large decreases in enthalpy and entropy were observed, while the standard free energy change was small. The results suggest that the intermediate showing the ATP-form of difference spectrum hardly changes to the forward direction in the ATPase reaction at higher temperature. The complex appears to be so stable in the steady state that almost all the myosin is present as this complex. The decay step in ATPase of the difference spectrum from the ATP-form to to the ADP-form may be coupled to muscular contraction. The temperature induced transition of heavy meromyosin AMP-PNP complex may, therefore, provide information concerning the state of myosin in active muscles.
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PMID:Temperature induced analog reaction of adenylyl imidodiphosphate to an intermediate step of heavy meromyosin adenosine triphosphatase. 13 5

Fast (extensor digitorum longus) and slow (soleus) rat skeletal muscles served as the source for isolation and biochemical comparison of two distinct surface membrane fractions with properties of the sarcolemma and transverse tubular system. Enriched sarcolemmal membrane from soleus demonstrated a lighter density after sucrose density centrifugation. Sialic acid content was 1.5-fold higher in soleus (62 nmol/mg) than extensor (40 nmol/mg). The specific activity of (Na+ + K+ + Mg2+)-ATPase was similar (1.40 and 1.65 micronmol Pi/mg per 5 min) with the soleus enzyme displaying a (1) greater resistance to inhibition by ouabain, and (2) broader ionic ratio (Na+/K+) requirement than extensor enzyme. The polypeptide and phospholipid composition showed no major differences between the two muscle types. The second surface membrane fraction, tentatively identified as transverse tubule, differed in membrane composition. The major polypeptide of extensor was of 95 000 molecular weight whereas for soleus a Mr=28 000 species was dominant. Total phospholipid content of soleus was 1.5-fold greater than extensor due mostly to increased levels of phosphatidylcholine and phosphatidylethanolamine. Endogenous membrane protein kinase for the 28 000 molecular weight polypeptide was found exclusively in this membrane. The reaction conditions were identical for extensor and soleus since both required divalent cations (Ca2+ and Mg2+) and neither was affected by cyclic AMP. Soleus showed a 2-fold higher capacity for phosphate incorporation than extensor. These studies show that surface membrane fractions derived from fast and slow muscles differ in terms of functional and compositional properties. These differences are specific not only for the surface membrane but for the muscle type and may relate to the known physiological differences observed between fast and slow mammalian muscle.
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PMID:Isolation and characterization of the surface membranes of fast and slow mammalian skeletal muscle. 13 21

Human adult lung fragments removed from macroscopically undamaged and anthracosis exempted zones of lungs of 20 pneumonectomies made for cancer, were tested for 25 enzymic activities. The location and intensities of these enzymic activities were different in the lung tissue components; The bronchial epithelia contained highly active LDH, MDH, SDH, NADH-TR and NADPH-TR, glucose-6-phosphate dehydrogenase, active hydroxyproline-2-epimerase, alkaline phosphatase. Ca2+-activated ATP-ase, and beta-galactosidase. Bronchial and vascular muscles presented intense activities of LDH, MDH and SDH of alkalinephosphatase, AMP-ase and Ca2+-activated ATP-ase, as well as of beta-galactosidase. The alveolar walls presented high activities of SDH, MDH and LDH, of alkaline and acid phosphatases, of beta-galactosidase and of Tween-40 and 60-esterases, of HEP, cytochrome-oxidase and peroxidase. The free alveolar macrophages were active for LDH, MDH, SDH, NADH-TR and NADPH-TR, G1-6-ph-DH, acid and alkaline phosphatase, cytochrome-oxidase and peroxidase, HEP, AMP-ase and Mg2+-activated ATP-ase, Tween-esterases, naphthol-ASD-acetate esterase, and beta-galactosidase. The endothelia contained high activities of alkaline phosphatase, of AMP-ase and Mg2+-activated ATPase, of LDH, MDH and SDH, and of beta-galactosidase. In bronchial lymphoid nodules it was the LDH, MDH, SDH, cytochrome-oxidase and peroxidase, HEP, alkaline phosphatase and AMP-ase, Tween-60-esterase and beta-galactosidase that were active. The interlobular areas of the lung presented intense activities of SDH, MDH, LDH, HEP and cytochrome-oxidase. The activities of the other tested enzymes were weaker or absent in the adult human lung components, the same as those of aminopeptidases which were present only in some free alveolar macrophages. The discussion of some relationships between these enzymic actitivies and the morphology of the human adult lung tissue asserted that the latter could not be considered as a "normal" tissue but as one overstrained by the components of blood and polluted air.
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PMID:Histoenzymology of the lung. I. Enzyme activities of the lung tissue of acult humans; relationships between structure and functions. 14 Mar 14

1. The specific activity of rat and pig liver nuclear-envelope nucleoside triphosphatase (EC 3.6.1.3) decreases when the system is depleted of RNA. The activity can be restored by adding high concentrations of yeast RNA to the assay medium. 2. Exogenous RNA also increases the activity of the enzyme in control envelopes (not RNA-depleted). The effect appears to be largely specific for poly(A) and poly(G); it is not stimulated by rRNA or tRNA preparations, ribonuclease-hydrolysed RNA, AMP, or double- or single-stranded DNA. 3. Inhibitors of the enzyme, in concentrations at which half-maximal inhibition of the enzyme is achieved, do not affect the percentage stimulation of the enzyme by yeast RNA. 4. The simulation is abolished by the inclusion of 150 mM-KCl or -NaCl in the assay medium, but not by increasing the assay pH to 8.5. 5. The results are discussed in the light of the possible role of the nucleoside triphosphatase in vivo in nucleo-cytoplasmic ribonucleoprotein translocation. 6. It is proposed that poly(G)-stimulated Mg2+-activated adenosine triphosphatase activity should be adopted as an enzymic marker for the nuclear envelope.
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PMID:Ribonucleic acid stimulation of mammalian liver nuclear-envelope nucleoside triphosphatase. A possible enzymic marker for the nuclear envelope. 14 Dec 76


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