Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.1.3 (ATPase)
 65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In Goldblatt rats (GV) 4-24 weeks after coarctation of one renal artery the following characteristics were registered as compared to controls (CV) of the same age: Arterial blood pressure increased to 190-200 mmHg in comparison to 105-110 mmHg in controls. This pressure overload induced an increase in ventricular weights (34%-54%). Noteworthy differences in myocardial water, total protein, and nonprotein substance contents were found. Hydroxyproline concentration in GV did not increase significantly until 24 weeks after onset of pressure overload. No significant alterations were detected in the relationship of myocardial, sarcoplasmic, and stromal protein fractions. However, greater changes could be registered in the concentration of the myofibrillar protein fraction and its single components. Furthermore, a correlative depression in specific actomyosin ATPase activity and in maximum shortening velocity of the unloaded cardiac muscle (2,3) was observed.
 ...
PMID:Characteristics of the hypertrophied left ventricular myocardium in Goldblatt rats. 14 Jun 72

Experiments were performed to investigate whether the inhibitory effect of ethanol on intestinal glucose transport is related to its action on the brush border or on the ATPase-dependent sodium pump of the basolateral membrane of the enterocyte. We compared the effect of ethanol on glucose and water transport when it was added either to the mucosal or to the serosal solution of an in vitro preparation of hamster jejunum. The purpose of the addition of ethanol to the serosal solution was to mimic a situation similar to that produced when ouabain is placed on the serosal side to inhibit the ATPase-dependent sodium pump at the basolateral membrane. The presence of 450 mM ethanol (2.07%) in the mucosal solution depressed glucose and water transport by 40 and 63%, respectively, but the presence of the same concentration of ethanol on the serosal side had no effect on glucose and water absorption. These findings seem to indicate that the depressing effect of ethanol on intestinal glucose and water transport cannot be ascribed to the inhibition of the Na+, K+-sensitive ATPase-dependent sodium pump located at the basolateral membrane.
 ...
PMID:On the mechanism of the inhibitory effect of ethanol on intestinal glucose and water absorption. 14 Dec 6

Water extracts of the bark of Mansonia altissima var altissima inhibit the activity of the Na+, K+-ATPase of Rabbit brain microsomes. The kinetics of hydrolysis of ATP show non-competitive inhibition analogous to that produced by ouabain.
 ...
PMID:[Inhibition of microsomal Na+ K+ ATPase of the brain by extracts of Mansonia altissima]. 14 82

Mg2+-Dependent, Ca2+-activated adenosine triphosphatase (E. C. 3.6.1.4) of synaptosomal plasmatic membrane from cow brain catalyses isotopic exchange of oxygen atoms: KH2P18O 4 in equilibrium H2O, the degree of exchange depending on Ca2+ concentration. The 18O-exchange catalysis suggests that the enzyme under consideration acts as a transport ATPase.
 ...
PMID:[Oxygen isotope exchange reactions in synaptosomal plasmatic membrane system]. 14 26

The profile structure of functional sarcoplasmic reticulum (SR) membranes was investigated by X-ray diffraction methods to a resolution of 10 A. The lamellar diffraction data from hydrated oriented multilayers of SR vesicles showed monotonically increasing widths for higher order lamellar reflections, indicative of simple lattice disorder within the multilayer. A generalized Patterson function analysis, previously developed for treating lamellar diffraction from lattice-disordered multilayers, was used to identify the autocorrelation function of the unit cell electron density profile. Subsequent deconvolution of this autocorrelation function provided the most probable unit cell electron density profile of the SR vesicle membrane pair. The resulting single membrane profile possesses marked asymmetry, suggesting that a major portion of the Ca++ -ATPase resides on the exterior of the vesicle. The electron density profile also suggests that the Ca++-dependent ATPase penetrates into the lipid hydrocarbon core of the SR membrane. Under conditions suitable for X-ray analysis, SR vesicles prepared as partially dehydrated oriented multilayers are shown to conserve most of their ATP-induced Ca++ uptake functionality, as monitored spectrophotometrically with the Ca++ indicator arsenazo III. This has been verified both in resuspensions of SR after centrifugation and slow partial dehydration, and directly in SR multilayers in a partially dehydrated state (20-30 percent water). Therefore, the profile structure of the SR membrane that we have determined may closely resemble that found in vivo.
 ...
PMID:A direct analysis of lamellar x-ray diffraction from hydrated oriented multilayers of fully functional sarcoplasmic reticulum. 14 69

The distribution of Na+ pump sites (Na+-K+-ATPase) in the secretory epithelium of the avian salt gland was demonstrated by freeze-dry autoradiographic analysis of [(3)H] ouabain binding sites. Kinetic studies indicated that near saturation of tissue binding sites occurred when slices of salt glands from salt-stressed ducks were exposed to 2.2 muM ouabain (containing 5 muCi/ml [(3)H]ouabain) for 90 min. Washing with label-free Ringer's solution for 90 min extracted only 10% of the inhibitor, an amount which corresponded to ouabain present in the tissue spaces labeled by [(14)C]insulin. Increasing the KCl concentration of the incubation medium reduced the rate of ouabain binding but not the maximal amount bound. In contrast to the low level of ouabain binding to salt glands of ducks maintained on a freshwater regimen, exposure to a salt water diet led to a more than threefold increase in binding within 9-11 days. This increase paralleled the similar increment in Na+-K+-ATPase activity described previously. [(3)H]ouabain binding sites were localized autoradiographically to the folded basolateral plasma membrane of the principal secretory cells. The luminal surfaces of these cells were unlabeled. Mitotically active peripheral cells were also unlabeled. The cell-specific pattern of [(3)H]ouabain binding to principal secretory cells and the membrane-specific localization of binding sites to the nonluminal surfaces of these cells were identical to the distribution of Na+-K+-ATPase as reflected by the cytochemical localization of ouabain-sensitive and K+-dependent nitrophenyl phosphatase activity. The relationship between the nonluminal localization of Na+-K+-ATPase and the possible role of the enzyme n NaCl secretion is considered in the light of physiological data on electrolyte transport in salt glands and other secretory epithelia.
 ...
PMID:Basolateral plasma membrane localiztion of ouabain-sensitive sodium transport sites in the secretory epithelium of the avian salt gland. 14 41

The enzymatic properties of membrane-bound Na+ + K+-ATPase from gills of killifish acclimated to fresh water, to 16% sea water, or to 30% sea water appear to be identical, indicating that the same enzyme may function to absorb Na+ in low salinities and excrete Na+ at the gills in high salinities. Ammonium ion is an effective substitute for K+: in the ATPase reaction itself, in blocking phosphorylation of the ATPase protein, and in inhibiting the binding of ouabain to the enzyme. The specific activities of the Na+ + K+-ATPase in the three different salinities are consistent with the expected Na+ pumping rates: higher in fresh water and 30% sea water than in 16% sea water. Within one-half hour after transfer of killifish from one salinity to another, gill Na+ + K+-ATPase activities reach equilibrium levels. The rapid increase in Na+ + K+-ATPase activity in gill microsomes of fish acclimating from fresh water to 30% sea water is accompanied by a slow decrease in the number of binding sites for ouabain, supporting the idea that acclimation to short-term salinity changes may involve modifications in the catalytic rate rather than the number of Na+ + K+-ATPase molecules.
 ...
PMID:Rapid modulation of gill Na+ + K+-dependent ATPase activity during acclimation of the killifish Fundulus heteroclitus to salinity change. 14 75

The effects of the ionophore lysocellin on the movements of Ca2+, Mg2+ and alkali metal cations and its effect on energy utilization by rat liver mitochondria have been investigated. At a concentration of 0.05 micrometer, lysocellin induced dissociation of membrane-bound calcium, and an apparent steady state was established across the inner membrane between energy-linked calcium accumulation and the ionophore-induced depletion of calcium. No detectable efflux of intramitochondrial Ca2+ and Mg2+ was induced by 0.05 micrometer lysocellin, but the uptake of exogenously added calcium was significantly inhibited. The ionophore augmented Mg2+ release from mitochondria induced by Ca2+ addition and also caused rapid release of K+ from mitochondria preloaded with K+ by valinomycin or monazomycin. High levels (0.5 approximately 10 micrometer of lysocellin caused massive depletion of endogenous Ca2+, Mg2+ and K+ from mitochondria, resulting in disruption of mitochondrial functions including release of state 4 respiration, stimulation of ATPase and inhibition of ADP- or DNP-stimulated respiration. Structure-activity studies with chemically modified compounds of lysocellin indicated the important role of terminal carboxylic acid and C21 hydroxyl function in the activity of the ionophore, and there is a good correlation between the effect of lysocellin on mitochondrial cation movements and its ability to complex with cations determined in an organic solvent-water two-phase partition system.
 ...
PMID:Studies on the ionophorous antibiotics. XII. Effects of ionophore lysocellin on cation distribution and respiration in mitochondria. 14 23

Ghost membranes prepared from human erythrocytes exhibit 2 distinct (Ca + Mg)-ATPase1 activities (Quist and Roufogalis, Arch Biochem Biophys 168:240, 1975). (Ca + Mg)-ATPase activity dependent on a water soluble protein fraction is selectively lost from ghost membranes during preparation of vesicles under low ionic strength, slightly alkaline conditions. In this study, the Ca2+ dependence of the remaining membrane bound (Ca + Mg)-ATPase activity and ATP-dependent Ca uptake in vesicles were compared. The Ca2+ activation curves for (Ca + Mg)-ATPase activity and Ca uptake into vesicles were parallel over a Ca2+ range of 0.3-330 micrometer, and both curves have 2 apparent KA values for Ca2+ of 0.45 and 100 micrometer. Addition of a concentrated soluble protein fraction containing predominantly spectrin to the vesicles increased (Ca + Mg)-ATPase activity over twofold but did not affect the rate of Ca uptake. These findings suggest that the (Ca + Mg)-ATPase activity remaining in vesicles after extraction of the water soluble proteins is associated with the Ca pump whereas (Ca + Mg)-ATPase activity dependent on the soluble protein fraction is associated with some other function.
 ...
PMID:Association of (Ca + Mg)-ATPase activity with ATP-dependent Ca uptake in vesicles prepared from human erythrocytes. 14 17

The short circuit current and the open circuit voltage responses of membranes to ATP, which have been attributed to membrane ATPase acting as a sodium pump, have been reproduced not only in a lipid membrane containing solubilized ATPase but also in membranes formed of the phospholipids contained in ATPase. The response is greatest with cardiolipin, but occurs with other acidic phospholipids. This observation of electrogenesis without hydrolysis is a surface phenomenon probably due to the alignment of ATP on the phospholipid by ion association at its interface with the water phase. The finding constitutes a precaution for interpreting studies of membrane Na-K-ATPase or for its incorporation into an artificial membrane. The substances necessary for electrogenesis are present at the mitochondrial membrane, and the particular orientation of the ATP on the phospholipids in vitro suggests a role for this ion association in the function of Na-K-ATPase.
 ...
PMID:Electrogenesis from an ATPase-ATP-sodium pseudo pump. 14 90


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>