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)

Sarcolemmal membranes were isolated from porcine skeletal muscle by modifications of a LiBr-extraction technique. Latency determinations of acetylcholinesterase, ouabain-sensitive p-nitrophenylphosphatase, [3H]ouabain binding, and (Na+ + K+)-ATPase activities indicated that 65-76% of the membranes were sealed inside-out vesicles. The preparations were enriched in cholesterol and phospholipid, and demonstrated adenylate cyclase activity and both cAMP and cGMP phosphodiesterase activities. An indication of the purity of this fraction was that the Ca2+-ATPase activity (0.13 mumol Pi mg-1 min-1 at 37 degrees C) was 3.8% of that of porcine skeletal muscle sarcoplasmic reticulum preparations. Pertussis toxin specifically catalyzed the ADP-ribosylation of a Mr 41,000 sarcolemmal protein, indicating the presence of the inhibitory guanine nucleotide regulatory protein of adenylate cyclase, Ni. An endogenous ADP-ribosyltransferase activity, with several membrane protein substrates, was also demonstrated. The addition of exogenous cAMP-dependent protein kinase or calmodulin promoted the phosphorylation of a number of sarcolemmal proteins. The calmodulin-dependent phosphorylation exhibited an approximate K 1/2 for Ca2+ of 0.5 microM, and an approximate K 1/2 for calmodulin of 0.1 microM. 125I-Calmodulin affinity labeling of the sarcolemma, using dithiobis(succinimidyl propionate), demonstrated the presence of Mr 160,000 and 280,000 calmodulin-binding components in these membranes. These results demonstrate that this porcine preparation will be valuable in the study of skeletal muscle sarcolemmal ion transport, protein and hormonal receptors, and protein kinase-catalyzed phosphorylation.
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PMID:Components of purified sarcolemma from porcine skeletal muscle. 299 26

The neural membrane-bound enzymes, acetylcholinesterase, Na/K-ATPase and Ca-ATPase were examined in six brain areas in perinatal rats at 5, 15 and 25 days of age following alcohol exposure in utero. Female Wistar rats were mated with adult male Wistar rats and maintained on either a liquid diet containing ethanol (5% w/v) or on a control liquid diet for various periods during gestation and the perinatal period. These periods were: before and during gestation only (until birth of the offspring); before and during gestation and following birth; during only a period of gestation and continuing postnatally. Enzyme activity was determined by spectrophotometric methods in the following areas of the brain in each offspring: telencephalon, cerebellum, hippocampus, septal area, preoptic area, and medial basal hypothalamic area. Analysis of the data indicates that alcohol exposure in utero will heterogeneously decrease enzyme activity among the six brain areas when compared to enzyme activity in the same brain areas in animals which were not exposed to alcohol in utero. The activity of the three enzymes were most significantly reduced on day 5 of age, compared to levels in the control animals. Enzyme activity in each brain area was generally most significantly affected in animals exposed to alcohol both pre- and postnatally. The results indicate that fetal alcohol exposure reduces neuronal enzyme activity relative to the period of ethanol exposure in utero; the longer the period of time that alcohol was consumed by the mothers pre- and postnatally, the greater the effect of alcohol on the enzyme activity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The effects of alcohol exposure in utero on acetylcholinesterase, Na/K-ATPase and Ca-ATPase activities in six regions of rat brain. 300 3

Cerebral ischemia produced a decrease in Na+, K+-ATPase activity in striatum and cortex; acetylcholinesterase activity was not affected in either region. Pretreatment of the animals with CDPcholine and CDPethanolamine did not prevent the decline in ATPase activity, suggesting that the accumulation of free fatty acids associated with ischemia is not responsible for these changes. Addition of exogenous diacylglycerols to the ATPase assay mixture produced an inhibition of the enzyme similar in magnitude to that observed in tissue samples from ischemic brain. These results support our hypothesis that the local accumulation of diacylglycerols following ischemia is involved in the observed changes in enzymatic activity.
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PMID:The effects of ischemia and CDPamines on Na+, K+-ATPase and acetylcholinesterase activities in rat brain. 300 46

The non-endplate (sarcoplasmic) acetylcholinesterase (AChE) was investigated in eight different muscles of the rat. Serial consecutive sections were stained for AChE, myofibrillar ATPase (after alkaline and acid preincubation), and cytochrome C-oxidase. The following general correlation could be established: within a given muscle the sarcoplasmic AChE was highest in type IIB fibers, lowest in type I and intermediate in type IIA. Additionally, the intensity of the reaction was directly proportional to the size of the type IIA fibers. The distribution of sarcoplasmic AChE was correlated to the ATPase fiber types but was complementary to the cytochrome C-oxidase staining pattern. In single fiber preparations, accumulation of AChE at the myotendinous junction was found to occur in "cap-like" form exclusively in fibers with very low or absent sarcoplasmic AChE. To study the role of innervation in the expression of the sarcoplasmic AChE, we cross-reinnervated the extensor digitorum longus (EDL) muscle with the soleus (SOL) nerve and vice versa (X-EDL, X-SOL). In the X-EDL the sarcoplasmic AChE was transformed to that of a normal SOL as were also the ATPase and the cytochrome oxidase. Surprisingly, in the X-SOL the high AChE activity typical for a normal EDL was present after 3 weeks but decreased steadily to very low levels lacking any correlation with ATPase and cytochrome oxidase. The results suggest that the cytoplasmic AChE of the SOL muscle depends more on the load-bearing function of the muscle than on the imposed impulse pattern. There is additional evidence for a retrograde effect of the X-SOL upon its motoneurons.
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PMID:Fiber type and non-endplate acetylcholinesterase in normal and experimentally altered muscles. 300 93

Short-term hypothermia, caused by cooling of rats down to 20 degrees, decreased distinctly the Na+, K+-ATPase activity in brain homogenates incubated at 37 degrees and did not affect the enzyme activity in the homogenates incubated at 20 degrees. The longer hypothermia (2 hrs at 20 degrees) did not affect the Na+, K+-ATPase activity at 37 degrees (during incubation) and decreased the enzymatic activity in homogenates of middle brain and diencephalon at 20 degrees during the incubation. Contrary to Na+, K+-ATPase, the activity of acetylcholinesterase was markedly increased in brain tissues of rats with hypothermia (irrespective of the temperature of incubation) as compared with control animals.
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PMID:[ATPase and acetylcholinesterase activity of the brain in hypothermia]. 301 May 68

The effect of cholesterol enrichment and depletion of rabbit erythrocytes on the activities of membrane-bound enzymes, namely (Na+,K+)-stimulated ATPase, NAD+ase and acetylcholinesterase was examined. The cholesterol content of erythrocyte membranes has been modified by incubation of intact cells with sonicated egg lecithin/cholesterol vesicles (cholesterol/phospholipid molar ratio approx. 2) and with egg lecithin vesicles for time intervals up to 10 hours. The cholesterol/phospholipid molar ratio (CH/PL) of untreated rabbit red blood cell membranes was 0.92-0.94. Linear increase (up to CH/PL molar ratio 1.72-1.9) or decrease (up to CH/PL molar ratio 0.27-0.43) in cholesterol content of erythrocyte membranes was observed over the 10 hours of incubation with egg lecithin/cholesterol and egg lecithin liposomes respectively. Fusion of liposomes to the membrane or their attachment to the membrane surface was not a significant factor in the alteration of CH/PL ratio. (Na+,K+)-stimulated ATPase, NAD+ase and acetylcholinesterase activities were measured as a function of membrane cholesterol. The specific activities of all three enzymes were progressively decreased with increase in cholesterol content. Partial reversibility of the inhibitory effect of cholesterol was demonstrated by measurement on cells depleted again after cholesterol enrichment. This was confirmed by the fact that a lowering in cholesterol content evoked an analogous activation of enzymes. The possible implications of physicochemical modifications of bulk and annular lipids of membrane-bound enzymes in the inhibition mechanism are discussed.
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PMID:Alterations in the activities of rabbit erythrocyte membrane-bound enzymes induced by cholesterol enrichment and depletion procedures. 301 May 90

Neuronal membrane enzyme activities were determined in naive and ethanol-treated (30 min after 2 g/kg) male and female rats of lines developed for more (ANT) and less (AT) ethanol-induced motor impairment. Ethanol did not affect acetylcholinesterase, (Na+K)-ATPase or 5'-nucleotidase activities, but adenylate cyclase activities were lowered in both cerebellum and cerebrum. Cerebral acetylcholinesterase activities were higher in ANT than AT rats. No consistent line difference was observed regarding (Na+K)-ATPase activities. Slightly higher cerebellar 5'-nucleotidase activities were found in the ANT line. Cerebellar adenylate cyclase levels were substantially higher in the AT line. No line differences were displayed in the activation of adenylate cyclase activity by dopamine or norepinephrine. It is concluded that ethanol in vivo may inhibit neuronal adenylate cyclase activity and that cerebellar phosphorylation may be a regulator of motor impairment. Cholinergic mechanisms may also be connected to the ethanol-induced motor impairment.
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PMID:Neuronal membrane enzymes in rat lines selected for differential motor impairment by ethanol. 301 92

The effect of Ep on different ATPases and acetylcholinesterase of rat RBC membrane was studied. Starvation caused a slight decrease in Mg2+-, Ca2+-, and Na+ + K+-ATPases. However, these enzyme activities were markedly increased on Ep treatment of starved rats. Specific activities of all three ATPases increased linearly with increasing concentration of Ep. Under identical conditions the hormone failed to stimulate the ATPase activity of liver plasma membrane. Desensitization by fluoride of allosteric inhibition of erythrocyte membrane-bound Na+ + K+-ATPase was observed under starvation which showed a return to normal n values on Ep administration. The enzyme from normal animals was inhibited almost completely at 0.1 mM fluoride whereas enzyme from starved and Ep-treated animals showed only about 50% inhibition at that fluoride concentration. Ep increased the acetylcholinesterase activity of normal RBC membrane to a small extent whereas the stimulation was much higher under starvation. The fluoride inhibition curve of this enzyme changed from sigmoidal to hyperbolic under starvation which again changed to allosteric on administration of Ep. These changes were closely correlated to n values. Red blood cells of Ep-treated animals became more susceptible to osmotic shock under the experimental conditions.
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PMID:Effect of erythropoietin on the different ATPases and acetylcholinesterase of rat RBC membrane. 302 76

Adriamycin (ADR) increased the lipid fluidity of dog brain synaptosomal plasma membranes (SPM) labeled with 1,6-diphenyl-1,3,5-hexatriene (DPH), as indicated by the steady-state fluorescence anisotropy [(ro/r)-1]-1. Arrhenius-type plots of [(ro/r)-1]-1 indicated that the lipid phase separation of the membrane at 23.3 +/- 1.2 degrees was perturbed by ADR such that the temperature was reduced to 16.2 +/- 1.1 degrees. Arrhenius plots of (Na+ + K+)-stimulated ATPase activity exhibited a break point at 22.8 +/- 1.1 degrees in control SPM which was reduced to 15.8 +/- 1.0 degrees in ADR treated SPM, suggesting differences in the interaction of (Na+ + K+)-stimulated ATPase with lipids between ADR treated and untreated SPM. (Na+ + K+)-stimulated ATPase and Ca2+-stimulated ATPase activities were increased at a concentration range 10(-18)-10(-15) M of ADR; higher concentrations (up to 10(-7) M), however, led to a progressive inhibition of the enzyme activities. The allosteric properties of SPM-bound (Na+ + K+)-stimulated ATPase by fluoride (F-) (as reflected by changes in the Hill coefficient) were modulated by ADR whereas those of SPM-bound acetylcholinesterase remained unaffected. We propose that ADR achieves these effects through asymmetric perturbations of the membrane lipid structure and that changes in membrane fluidity may be an early key event in ADR induced neurotoxicity.
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PMID:Evaluation of membrane fluidity effects and enzyme activities alterations in adriamycin neurotoxicity. 303 5

Previous biochemical findings suggest that exogenous gangliosides enhance cholinergic sprouting in the hippocampus after partial lesions of the septohippocampal pathway. To assess whether GM1 ganglioside accelerates the onset of this sprouting after complete lesions, we measured cholinergic enzymes and Na,K-ATPase activity in the hippocampus of rats with unilateral fimbria-fornix transection. At 14 and 18 days postlesion, histochemical staining showed that acetylcholinesterase (AChE) was almost completely eliminated in the hippocampus ipsilateral to the transection in untreated and GM1-treated rats. Biochemical assays confirmed that GM1 treatments did not increase AChE activity in the denervated hippocampus. Rather, there were significant reductions of AChE and choline acetyltransferase activities in the ipsilateral hippocampus relative to the contralateral value (P less than .001); and the reductions were greater in GM1-treated rats than in untreated controls (P less than .001). Na,K-ATPase activity in the ipsilateral hippocampus increased by 10.1% in GM1-treated rats, whereas it decreased by 21.7% in untreated controls (P less than .05). Since Na, K-ATPase is enriched in synaptic membranes, the increased activity of this enzyme may indicate that GM1 treatments stabilize surviving synaptic membranes and/or accelerate the onset of sprouting in the denervated hippocampus. The reductions in cholinergic enzymes, however, imply that the sprouting pathway must be noncholinergic.
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PMID:Ganglioside-induced alterations in hippocampal cholinergic enzymes and Na,K-ATPase after fimbria-fornix transection. 303 57


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