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)

We have previously shown that acute coronary occlusion in the dog is often accompanied by increased adrenaline release into the blood. In the present study the consequences of this humoral reaction were studied in anaesthetised healthy mongrel dogs subjected to adrenaline infusion administered at a rate relevant to spontaneous release of this amine in coronary occlusion. Adrenaline was infused in a dose of 1.2 microgram.kg-1.min-1 for 4 h. Dogs receiving saline served as the control. Adrenaline administration led to the decrease in insulin/glucose ratio, to a significant fall in serum triiodothyronine and in blood pH. Free fatty acid levels doubled. Histochemically, a diminution in succinic dehydrogenase and ATPase activity in adrenaline-treated hearts was found. A significant fall in the activity of mitochondrial hexokinase in these hearts was detected spectrophotometrically. Electron microscopic study revealed alterations in the mitochondrial structure. These findings indicate that an excess of adrenaline in ammounts similar to that seen in experimental infarction leads to profound metabolic and hormonal disturbances and exerts a detrimental effect upon myocardium.
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PMID:Evidence for the detrimental effect of adrenaline infused to healthy dogs in doses imitating spontaneous secretion after coronary occlusion. 2 14

Rabbit heart membranes possessing the adenylate cyclase activity were isolated and purified by extraction with high ionic strength solutions and centrifugation in the sucrose density gradient. It was shown that the membranes are characterized by a high percentage of cholesterol (molar ratio cholesterol/phospholipids is 0.24) and an increased activity of Na, K-ATPase, which suggests the localization of adenylate cyclase in the sarcolemma. During centrifugation in the sucrose density gradient the activities of andenylate cyclase and Na,K-ATPase are not separated. Treatment of heart sarcolemma with a 0.3% solution of lubrol WX results in 10--20% solubilization of adenylate cyclase. Purification of the enzyme in the membrane fraction is accompanied by a decrease in the activity of phosphodiesterase; however, about 2% of the heart diesterase total activity cannot be removed from the sarcolemma even after its treatment with 0.3% lubrol WX. Epinephrine and NaF activate adenylate cyclase without changing the pH dependence of the enzyme. The alpha-adrenergic antagonist phentolamine has no effect on the adenylate cyclase activation by catecholamines, glucagon and histamine; the beta-adrenergic antagonist alprenolol competitively inhibits the effects of isoproterenol, epinephrine and norepinephrine, having no effect on the enzyme activation by glucagon and histamine. There is no competition between epinephrine, glucagon and histamine for the binding site of the hormone; however, there may occur a competition between the hormone receptors for the binding to the enzyme. A combined action of several hormones on the membranes results in the averaging of their individual activating effects. When the hormones were added one after another, the extent of adenylate cyclase activation corresponded to that induced by the first hormone; the activation was insensitive to the effect of the second hormone added. It is assumed that the outer membrane of myocardium cells contains a adenylate cyclase and three types of receptors, each being capable to interact with the same form of enzyme. The activity of adenylate cyclase is determined by the type of the receptor, to which it is bound and by the amount of the enzyme-receptor complex.
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PMID:[Isolation, purification and characterization of regulatory properties of adenylate cyclase from rabbit heart]. 2 49

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

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

Detergent extracts of isolated rat liver plasma membranes were analysed in two-dimensional immunoelectrophoresis against antiserum to plasma membranes. Enzyme staining of the immunoprecipitates revealed the presence of about ten antigens with nucleoside di- and triphosphatase activity. Most of these were earlier shown also to be NADH-neotetrazolium reductase active. In addition, two of these antigens exhibited L-leucyl-beta-naphthylamidase activity. As judged from autoradiography these plasma membrane antigens earlier characterized as multienzyme complexes bound [14C]epinephrine, and the same antigens were labelled regardless of whether membranes or membrane extracts were incubated with the radioactive hormone. The specificity of this binding was established in displacement experiments with unlabelled hormones or their analogues. Another hormone-binding antigen, also identified in the plasma membrane extract did not exhibit any known enzyme activity while three antigens with different enzyme activities had no epinephrine-binding capacity. [14C]Epinephrine-labelled plasma membrane extracts were chromatographed on Sepharose 4B and the fractions obtained were analysed in two-dimensional immunoelectrophoresis combined with autoradiography. Nucleoside di- and triphosphatases of high molecular weights (5000000) were associated with L-leucyl-beta-naphthylamidase activity, while no such associations were detected in a lower molecular weight region (70000). Further immunological studies on the various fractionated antigens provided evidence that at least two of them occurred in both low and high molecular weight fractions. Hormone-binding membrane components in varying concentrations were found throughout the eluted extract.
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PMID:Epinephrine-binding plasma-membrane antigens in rat liver. 17 Jan 4

Adenosine triphosphatase (ATPase) activity in erythrocyte membranes from patients with Duchenne dystrophy was inhibited by ouabain less than in normal individuals in assay systems containing high or low contents of salt. Epinephrine and cyclic adenosine monophosphate increased total ATPase activity in all samples, and epinephrine restored ouabain sensitivity to the Duchenne membranes. Basal adenyl cyclase activity in about twice that of controls. Epinephrine stimulated adenyl cyclase activity of normal membranes two to three times, but did not stimulate the enzyme in Duchenne membranes. These differences may reflect a genetic abnormality of the membrane.
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PMID:Biochemical abnormalities of erythrocyte membranes in Duchenne dystrophy. Adenosine triphosphatase and adenyl cyclase. 18 Sep 37

The effects of various interventions on the frequency-dependent increases in the contractility of the papillary muscles of monkeys were investigated. Ouabain (10(-6)M) and KCl-free Krebs-Ringer solution, which are known to inhibit membrane Na+,K+-ATPase (EC 3.6.1.3), abolished the frequency-dependent increases in the contractility of the papillary muscles. Epinephrine (4.5 X 10(8)M) or quinidine (1.3 X 10(-5)M), which are known not to inhibit the membrane Na+,K-ATPase at these concentrations, did not alter the frequency-dependent increases in the contractility. These results indicate that the frequency-dependent increases in the contractility might be mediated through an inhibition of the sarcolemmal Na+,K+-ATPase.
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PMID:Possible mechanism for the frequency-dependent increases in the cardiac contraction in monkey. 40 75

1. Membrane events accompanying adrenaline-stimulated Cl secretion by the isolated rabbit corneal epithelium were investigated with micro-electrodes. 2. Pulses of adrenaline (5 X 10(-10) M final concentration) delivered to either side of the epithelium produced a transient decrease in epithelial resistance occuring at the outer membrane of the squamous cell. This response was reversible and could be blocked completely by total Cl substitution with SO4. 3. Adrenaline generally produced a small transient increase in epithelial potential occuring also at the squamous cell outer membrane. Reversal potentials obtained for the adrenaline response were 45-1 mV for corneal potential and 22-8 mV for outer membrane. 4. Adrenaline always hyperpolarized epithelial potential when the tear side was bathed in Cl-free solution. Reversing the gradient (Cl-free on the stromal side) slowly and consistently changed the response to a depolarization which reached a steady level after 2 hr. 5. The reversal potential of the outer membrane for the adrenaline response was found to be a semilogarithmic function of the tear side Cl concentration over a broad range with a slope of 56 mV/decade. The reversal potential was zero at a tear side Cl concentration of 41-5 mM, which value may be taken to be representative of cell Cl concentration. 6. After abolishing the adrenaline response by perfusing both sides of the tissue with Cl-free solution, reintroduction of Cl to the stromal side led to a recovery of the epithelial potential response in the hyperpolarizing direction. The recovery of the response was inhibited by ouabain (10(-5) M). 7. The results supported the following model for the influence of adrenaline on anion transport in the epithelium: Cl is transported against an electrochemical potential gradient into the cells from the stromal side by an active process linked to Na-k activated ATPase. Normally a slight gradient exists from cells to tears favouring the passive outward diffusion of Cl. This latter process is enhanged by adrenaline, which increases cell cyclic AMP, in turn increasing the passive Cl permeability of the outer cellular membrane.
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PMID:Site and mode of adrenaline action on chloride transport across the rabbit corneal epithelium. 86 18

Little is known of how adrenal hormones pass from the interstitial to the vascular space. We have begun to examine the adrenal endothelium as a barrier to hormone passage, by the freeze-fracturing technique. The endothelium of both cortex and medulla is fenestrated. Fractures from both regions show endothelial cells to be extremely thin in regions where fenestrations are abundant. En face fractures show fenestrae disposed in tracts; the fenestrae reaching a distribution of 35/mu2. In both cortex and medulla there are areas of continuous endothelium which contain caveolae. Structures believed to represent fenestra diaphragms contain randomly disposed particles and occasional pits. We have not identified in replicas the central ring and pore described in thin-sectioned material (Elfvin, 1965). The main differences between freeze-fractured aspects of cortical and medullary endothelium are the greater abundance of caveolae in the medulla and the size of the fenestrae (fenestra rims in the medulla are 525-780 A in diameter; in the cortex 570-1660 A). These differences may reflect the different embryological origins of the medulla and cortex. While caveolae may participate in hormone transport, there is no evidence for this. In the medulla the caveolae are more numerous and may have a function not necessarily related to transport. Possibly, caveolae play a role in processing hormones and related substances. For example, ATP and specific proteins are released as well as epinephrine during exocytosis from chromaffin cells. Epinephrine enters the vascular space but ATP does not. ATPase enzymes are a common feature of caveolae of other endothelia and may occur as well in adrenal endothelium.
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PMID:Fenestrated endothelium of the adrenal gland: freeze-fracture studies. 111 58

Of a total of three Friesian cows, two of which had been treated with adrenalin before slaughter, Mm longissimus (LO), supraspinatus (SS), triceps brachii (TB) and rectus abdominis (RA) were sampled at different times post mortem (pm). pH, calpain/calpastatin activities and degradation of myofibrillar proteins, as evidenced by SDS-PAGE, were assessed. Contraction characteristics were measured by determining myofibrillar ATPase activities. Adrenalin treatment resulted in a high ultimate pH (6.48 +/- 0.40) and a faster decline pm of calpain I activity. The effect was similar in all four investigated muscles (72.4 +/- 5.4% decline at 24 h pm). The decline in calpain I activity in the control muscles was muscle-dependent and ranged from 22.8-74.3% at 24 h pm. Differences in ultimate pH did not lead to distinct rates of breakdown of proteins with molecular weights lower than that of myosin heavy chain. Calpastatin levels were muscle-dependent and correlated with myofibrillar ATPase activity (r = -0.99). In a second experiment Mm rectus abdominis (RA) and psoas major (PM) of adrenalin-treated (n = 6) and control (n = 6) Friesian-Holstein calves were sampled at 1 and 29 h pm for assessment of calpain activities. At seven days pm the M longissimus (LO) was sampled for tenderness evaluation. pH values were measured at 30 min, 4 h and 29 h pm. Adrenalin treatment resulted in a higher ultimate pH in the three muscles. Higher ultimate pH resulted in lower calpain activities in the RA at 29 h pm (P less than or equal to 0.025).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The role of ultimate pH in proteolysis and calpain/calpastatin activity in bovine muscle. 153 28


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