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)

An ATPase stimulated by HCO-3ions and other oxybases and inhibited by SCN- has been found in main excretory duct of rat submaxillary gland, a tissue, capable of actively secreting HCO-3ions. No such ATPase was found in the rabbit duct, which normally does not secrete HCO-3. The HCO-3ATPase was localized in the plasma membrane fraction of the homogenate, as evidenced by the marker 5'nucleotidase. The activities of the HCO-3ATPase increased in metabolic alkalosis and decreased in metabolic acidosis in parallel to secretion of HCO-3 and K+ ions by the rat salivary duct epithelium. In renal cortex tissue, where HCO-3 is actively reabsorbed respectively H+ is secreted, there was also found a parallel change in the activity of the HCO-3ATPase and the rate of active H+ secretion. These findings provide further evidence that the membrane-bound HCO-3ATPase is involved in active H+/HCO-3 transport. The HCO-3ATPase is not only stimulated by HCO-3 but also by other non transportable oxybases, a finding which indicates H+ rather than HCO-3 being the actively transported component of the buffer system. Small concentrations of K+ ions decrease the Km for HCO-3 and thus yield stimulation of the HCO-3-ATPase. Thport changing in parallel with that of H+/HCO-3 may be taken as indicative for a coupled K+-H+-exchange mechanism to which the HCO-3ATPase is linked.
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PMID:The role of HCO3-stimulated ATPase in buffer transport. 1 63

The existence of nonadrenergic, noncholinergic nerve components in the autonomic nervous system is now well established. They are strongly represented in the gastrointestinal tract of all vertebrates and have been identified in a variety of other organs, including lung, trachea, bladder, esophagus, eye, seminal vesicles, and possibly parts of the vascular and central nervous systems. Their ultrastructural identification and transmission properties are known and their physiological role is beginning to be understood, at least in the gastrointestinal tract. Evidence that ATP is the transmitter released from nonadrenergic, noncholinergic (purinergic) nerves includes: (a) synthesis and storage of ATP in nerves; (b) release of ATP from the nerves when they are stimulated; (c) exogenously applied ATP mimicking the action of nerve-released transmitter, both producing a specific increase in K+ conductance; (d) the presence of Mg-activated ATPase, 5'nucleotidase, and adenosine deaminase, enzymes, which inactivate ATP; (e) drugs (including 2-substituted imidazolines, 2,2'-pyridylisatogen and dipyridamole), that produce similar blocking or potentiating effects on the response to exogenously applied atp and nerve stimulation.
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PMID:Purine nucleotides. 1 17

Oral administration of a single dose of alpha-naphthyl-isothiocyanate (ANIT) to rats produced a conjugated hyperbilirubinaemia, maximal at 2 days and which subsided by 7. The activities of 3 liver plasma membrane enzymes, Mg-2+-ATPase, (Na-+-K-+)-ATPase and 5-nucleotidase, and serum bilirubin levels were studied for up to 7 days after treatment. Activities of the 3 enzymes were significantly decreased at 2 days after treatment and returned to normal by 7, thus varying inversely with the degree of hyperbilirubinaemia. Enzyme histochemistry used to demonstrate canalicular localization of Mg-2+-ATPase in sections of whole liver and of isolated plasma membrane pellets showed that the reduction in activity was not a uniform partial loss, but represented a range of reductions in most canaliculi with a few retaining normal staining intensity. The results suggest that after ANIT intoxication there is a membrane lesion which may be responsible for the observed hyperbilirubinaemia due to the failure of secretion of biliary constituents into the canaliculus. However, more direct studies are necessary to determine whether any one of these enzymes is directly involved in the transport of biliary constituents across the bile canalicular membrane.
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PMID:Alpha-naphthyl-isothiocyanate-induced cholestasis in the rat: studies of liver plasma membrane enzymes. 12 51

Electron microscopic cytochemical localization of Mg++-activated adenosine triphosphatase (Mg++-ATPase) and 5-nucleotidase (AMPase) was investigated in bile canaliculus-rich and bile duct-containing fractions isolated from rat liver. Comparative cyochemical studies between prefixed and non-prefixed fractions revealed that the activity of both enzymes could be detected in the fractions under appropriate experimental conditions. However, the cytochemical activity of AMPase was much more sensitive to glutaraldehyde than that of Mg++-ATPase. Mg++-ATPase and AMPase reaction products were localized primarily on bile canalicular microvilli, that is, along the outer (luminal) surface of canalicular plasma membranes, but they were never observed on bile ductal microvilli. AMPase was also detectable on lateral hepatic plasma membranes. Mg++-ATPase demonstrated by the cytochemical technique described is a reliable enzyme marker for isolated bile canalicular membranes. At high magnification, Mg++-ATPase reaction product was also observed on the microfilaments surrounding isolated bile canaliculi. The possibility that the reaction product on the pericanalicular microfilaments may result from the hydrolysis of ATP byan actomyosin ATPase-like enzyme associated with these filaments is briefly discussed.
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PMID:Electron microscopic cytochemical characterization of bile canaliculi and bile ducts in vitro. 12 97

A histochemical study of plasma-membrane associated enzymes in rat liver demonstrated a significant lesion 3 days after a single oral dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin). The complete loss of canalicular ATPase reaction in the parenchymal cells of the centrilobular zone remained the prominent feature of the liver throughout the 6-wk period studied. Involvement of the periportal and midzonal regions occurred in moribund animals and improvement in the health of two surviving animals at 9 mth was associated with a normal distribution of ATPase in the liver. Qualitative changes in 5-nucleotidase and acid phosphatase were secondary to the parenchymal cell damage. This lesion supports the morphological evidence, reported previously, that the parenchymal cell plasma-membrane is a specific subcellular site of the toxic action of dioxin.
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PMID:A histochemical study of the liver lesion induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin) in rats. 12 19

In the present paper the mechanism of the adenosine formation by a mixture of nerve ending and transmitter granula fractions was invesitgated. The adenosine formation in vivo is only possible via the whole degradation chain ATP - ADP - AMP - adenosine. The enzymes involved are ATPases, adenylate kinase and 5'-nucleotidase. The ATPase and adenylate kinase effectors Ca++ and Mg++ can be regarded as trigger ions switching on and off the degradation chain. The adenylate kinase represents a key enzyme within the whole chain. In the ion-activated state a non-inhibited adenosine formation was observed, when the initial ATP concentration amounted to less than 0,1 muMol per mg synaptosomal membrane protein. Under these conditions the whole chain velocity is mainly dependent on the 5'-nucleotidase concentration, because ATPases and adenylate kinase remove the nucleotidase inhibitors ATP and ADP spontanously. The conditions for the optimal velocity of the adenosine formation at the synaptic membrane in vivo in all probability are present. A hypothesis for the mechanism of the synaptic adenosine formation in vivo was developed. The importance of this process in respect to the synaptic transmission was discussed.
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PMID:[Mechanism of synaptosomal degradation of ATP in connection with involvement of adenosine in the transmission process]. 12 26

Proliferation of the vascular endothelium occurring in brain tumours is accompanied by a proliferation of histiocytes in the peripheral part of the vessel wall. These histiocytes infiltrate the tumour tissue in a very regular pattern. Enzyme-histochemically, there are marked differences between the activities of alkaline phosphatase, 5-nucleotidase, and ATPase in the normal and proliferating blood vessels. The whole process encompasses reactive changes evoked by the destroyed perivascular sheath of astroglial foot processes and the subsequent oedema in the tumour and the surrounding parenchyma. There are often tumour areas where diminished vascular permeability is established by proliferation of perivascular connective tissue. Here the oedema has completely disappeared. A clearcut influx of monocytes from the blood into the vessel wall is seen only in the vicinity of necrotic foci; the number of histiocytes is increased and their turnover is observed in swollen macrophages. In the rest of the tumour influx of monocytes and activity of macrophages are inconspicious.
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PMID:Proliferation of blood vessels and stroma in brain tumours. An enzyme-histochemical study. 13 51

The sarcolemma preparations isolated from the skeletal muscles of the normal rabbits and those with E-avitaminosis are characterized by electron microscopy according to the activity of 5-nucleotidase and different ATPase systems. As the data of electron microscopy evidence, the sarcolemma preparations of the normal and dystrophic muscles are deprived of admixtures of other subsellular structures. The 5-nucleotidase activity in the sarcolemma of dystrophic muscles is almost thrice as high as in the sarcolemma of normal muscles. On the basis of the results of studies in the kinetic parameters the optimal conditions are selected to investigate the Mg2+, Ca2+ and Na+, K+-ATPase activity. It is shown that under dystrophy the ATPase activity in the sarcolemma preparations in the presence of Ca2+ and Mg2+ does not change as compared to the norm. As to the Mg2+-dependent Na+, K+-ATPase system its activity in sarcolemma of muscles under dystrophy lowers noticeably. Ouabain-sensitive Na+, K+-ATPase of sarcolemma under dystrophy is considerably lower than at the normal level and is 4.1 and 12.1 mumol and phi n per 1 mg of protein for 1 h, respectively. Proceeding from the data on the changes in the lipid composition of sarcolemma of muscles with E-avitaminous dystrophy a problem is under discussion concerning dependence of the transport Na+, K+-ATPase activity on the structure of sarcolemma.
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PMID:[ATPase systems of the skeletal muscle sarcolemma in E-avitaminotic muscular dystrophy]. 13 29

In the present contribution a comparative study of histochemical mapping of the distribution of adenosine triphosphatase and 5-nucleotidase in the hind brain of mouse has been made. There are many similarities and dissimilarities between the distribution of these two enzymes in various nuclei, tracts and fiber bundles. The noteworthy differences are as follows:--1. The AP, NDNV, NI, NNH, NOAD, NOAM, NOI NPC, TS and SG are very intensely positive for ATPase whereas, in 5-NUC study none of these nuclei demonstrates intensity of such degree. 2. Nucleus ambiguus is intensely positive for ATPase and is completely negative for 5-NUC. 3. The nucleus n. facialis is intensely positive for ATPase and is moderately positive for 5-NUC. 4. NC, GN, PN, PCI and TC are completely negative for 5-NUC. In ATPase preparations only GN is negative and the rest of the areas demonstrate intensity of various degrees. Along with these differences, similarities in the intensity of both enzymes in various nuclei, tracts and fibrous bundles also exist. An attempt has been made to correlate all the aforesaid differences and similarities in the distribution of these two enzymes with the functional nature of the various areas of hind brain of mouse.
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PMID:Acomparative histochemical mapping of ATPase and 5-nucleotidase in the medulla oblongata, spinal cord and cerebellum of mouse. 15 Apr 46

The study deals with the distribution of acid and alkaline phosphatases, ATPase, 5-nucleotidase, nonspecific esterase, specific cholinesterase, and beta-galactosidase in the diencephalon of the frog. The highlights of the present study are the following: i) Acid phosphatase is present in all the neurons, whereas the tracts and commissures are completely negative. ii) Most of the tracts and commissures are positive for 5-nucleotidase. This confirms the author's previous findings that the tracts and commissures of all the areas of frog brain are intensely positive for 5-nucleotidase. iii) beta-galactosidase activity in the nuclei of the diencephalon is either mild or completely absent, whereas the commissures and tracts show positive activity. iv) Habenulothalamic connections are intensely positive for specific cholinesterase and non-specific esterase, moderately positive for beta-galactosidase and completely negative for other enzymes. v) The epiphysis (pineal organ) shows intense reaction for adenosine triphosphatase, acid phosphatase, and 5-nucleotidase and moderate reaction for alkaline phosphatase and non-specific esterase. In contrast to the above enzymes, the specific cholinesterase and beta-galactosidase are completely missing. vi) Lateral forebrain bundles are completely negative for all the enzymes except alkaline phosphatase and beta-galactosidase. The distribution of these enzymes has been correlated with the functional aspects of various nuclei, tracts, and commissures of the diencephalon of the frog.
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PMID:The chemoarchitectonics of the diencephalon of frog (Rana tigrina). 15 81


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