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 effects of salinomycin on alkali cation transport and membrane functions in rat liver mitochondria have been investigated. After potassium uptake, stimulated by valinomycin or monazomycin in the presence of adenosine 5'-triphosphate, salinomycin caused rapid release of K(+) from mitochondria. Salinomycin reversed valinomycin- or monazomycin-induced oscillatory swelling of mitochondria preloaded with K(+), Rb(+), and Na(+) but was without effect on Li(+) or Cs(+) preloaded mitochondria. Salinomycin blocked the retention of K(+) more effectively than the retention of Rb(+) or Na(+). Salinomycin inhibited both coupled and uncoupled respiration with strict substrate specificity in medium of low but not in high K(+) concentration. The oxidation of glutamate, alpha-ketoglutarate, and malate plus pyruvate was inhibited by salinomycin, but that of beta-hydroxybutyrate or succinate was not significantly affected. Salinomycin inhibited adenosine triphosphatase activity of mitochondria induced by valinomycin or monazomycin in K(+) and Rb(+) medium without significantly affecting adenosine triphosphatase activity in Li(+), Na(+), or Cs(+) medium. Oxidative phosphorylation in mitochondria was inhibited by salinomycin but the inhibitory effect of salinomycin lacked the substrate specificity observed for respiration. It is proposed that salinomycin perturbs mitochondrial functions by acting as a mobile carrier for alkali cations through membranes.
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PMID:Salinomycin effects on mitochondrial ion translocation and respiration. 13 9

It was found that some substances as aspartate, glutamate, atropine, physostigmine, ephedrine, caffeine and theophylline tended to alter the erythrocyte shape in the same concentration in which also the Mg++-dependent ATPase activity had been changed. The employment of various concentrations of barbiturate revealed that changes of the erythrocyte shape were dependent on its concentration. In the present study the relationship between Mg++-dependent ATPase and biconcave erythrocyte shape is discussed.
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PMID:The change of erythrocyte shape following action of different substances altering mg++-dependent ATPase activity (actomyosin-like protein). 13 56

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

Distinct morphological regions, initial, middle and terminal segments, were distinguishable histologically; the middle segment was further subdivided into proximal, intermediated and distal parts. PAS-positive, diastase-resistant reaction was detected in the blood vessels, subepithelial tissue and stereocilia of all segments. Acid phosphatase was demonstrated in the epithelial cells with the highest activity being in the proximal part of the middle segment. Non-specific esterase gave a similar reaction but the strongest activity was in the terminal segment. Alkaline phosphatase, adenosine triphosphatase and adenosine monophosphatase were of similar activity in the subepithelial tissue, blood vessels, stereocilia and luminal contents; the strongest reaction occurred in the middle segment. Lactate, succinate, glutamate and glucose-6-phosphate dehydrogenases were examined; LDH was more active than the others particularly in the terminal segment. Some reaction was found in the epithelial cells, subepithelial tissue and luminal contents.
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PMID:On the regional histology and histochemistry of the epididymis of the camel (Camelus dromedarius). 15 47

Mitochondria were isolated from Euglena gracilis strain Z by pressure-breakage of the cells and sucrose-cushion centrifugation. Multiple peaks (2-4) were observed in the rate of phosphorylation with Mg-ADP-phosphate concentration curves. The phosphorylative and oxidative activities were highest with NADH as the substrate, moderate with succinate, and lowest with glutamate. Inhibition of phosphorylation with 2,4-dinitrophenol and carbonyl cyanide, m-chlorophenylhydrazone gave sigmoidal concentration curves, with the extent of inhibition by DNP depending on the substrate used. Inhibition of phosphorylation by valinomycin, atractyloside, or carboxyatractyloside was only approximately 60%. Oligomycin inhibited phosphorylation in 2 phases at low and high concentrations; it inhibited Mg-ATPase in a sigmoidal fashion. Both phosphorylation and oxidation had discontinuities in Arrhenius plots at 34 C and 18 C. The relative Mg2+-dependent nucleoside triphosphatase activity was: 1 for ATP and GTP, 0.6 for ITP, 0.15 for CTP and UTP; with Ca2+ in place pf Mg2+ this activity was 0.35. Both DNP and CCCP stimulated the Mg-ATPase 50-200%. The optimal pH for the stimulation was approximately 7 regardless of the uncoupler used, and approximately 8 without the uncouplers. The few differences observed between mitochodria from Euglena and those from other sources are probably due to the fragmentation of the reticular mitochondrial structure during isolation and not to unique characteristics of these mitochondria.
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PMID:Some biochemical properties of mitochondria isolated from Euglena gracilis. 19 37

Carbamyl phosphate synthetase from Escherichia coli has been shown to use only the A isomer of adenosine-5'-[2-thiotriphosphate] in both the ATPase reaction (MgATP HCO3- leads to MgADP + Pi) and the carbamyl phosphate synthesis reaction (2MgATP + HCO3- + L-glutamine leads to 2MgADP + Pi + carbamyl-P + L-glutamate). The B isomer was less than 5% as reactive. In the reverse reaction, only the A isomer of adenosine-5'-[2-thiotriphosphate] is synthesized from adenosine-5'-[2-thiodiphosphate] and carbamyl-P as determined by 31P NMR and a coupled enzymatic assay with Cd2+- hexokinase. It is therefore proposed that carbamyl phosphate synthetase uses the same diastereomer of MgATP at both ATP sites.
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PMID:Carbamyl phosphate synthetase of Escherichia coli uses the same diastereomer of adenosine-5'-[2-thiotriphosphate] at both ATP sites. 21 Nov 24

The mitochondrial matrix subfractions from rat liver, kidney cortex, brain, heart, and skeletal muscle were isolated and their protein components were resolved by two-dimensional polyacrylamide gel electrophoresis, revealing between 120 and 150 components for each matrix subfraction. Excellent resolution was obtained utilizing a pH 5 to 8 gradient in the first dimension and in 8 to 13% exponential acrylamide gradient in the second dimension, increasing the number of mitochondrial matrix proteins observed 3-fold over one-dimensional systems. Protein components tentatively identified by co-migration with pure enzymes and by known tissue distributions are carbamoyl-phosphate synthetase (EC 2.7.2.5), ornithine transcarbamylase (EC 2.1.3.3), glutamate dehydrogenase (EC 1.4.1.3), pyruvate carboxylase (EC 6.4.1.1), citrate synthase (EC 4.1.3.7), fumarase (EC 4.2.1.2), aconitase (EC 4.2.1.3), alpha-ketoglutarate dehydrogenase (EC 1.2.4.2), dihydrolipoyl transsuccinylase (EC 2.3.1.12), lipoamide dehydrogenase (EC 1.6.4.3), glutamate-aspartate aminotransferase (EC 2.6.1.1), and the two subunits of pyruvate dehydrogenase (EC 1.2.4.1). Protein components unambiguously identified by peptide mapping are citrate synthase, aconitase, and pyruvate carboxylase. The inner membrane subfraction from rat liver mitochondria was also resolved two dimensionally; the alpha and beta subunits of ATPase (F1) (EC 3.6.1.3) were identified by peptide mapping.
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PMID:Resolution of rat mitochondrial matrix proteins by two-dimensional polyacrylamide gel electrophoresis. 44 63

1. The preparation of rat heart mitochondria with Potter-Elvehjem homogenizer results in mitochondria showing stimualtion of respiration induced by Mg2+. This stimualtion is neither caused by adherent hexokinase nor by energy-dependent magnesium accumulation (Mg2+ content in the presence of 10 mM glutamate: 22 nmoles/mg protein; in the presence of glutamate plus antimycin A 21 nmoles/mg protein). 2. The effect of added magnesium is excluded by addition of carboxyatractyloside. This demonstrates the activity of an ATPase outside of the mitochondrial inner membrane. 3. A simple and rapid method for the preparation of Mg2+-insensitive rat heart mitochondria is presented. The minced heart is pressed through a normal syringe and then treated with trypsin. 4. A comparison of mitochondria of both preparations shows that there is no difference in magnesium content and no energy-dependent magnesium influx.
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PMID:Influence of Mg2+-ions on the properties of rat heart mitochondria in dependence on the preparation. 70 27

Stria vascularis from guinea pig cochleae was incubated in vitro to determine its metabolic response to variations in substrate and ion composition of the incubation medium. The respiratory rate at 37 degrees C in a medium containing glucose and pyruvate as substrate was 17.3 +/- 1.33 (SEM, n = 51) microliter O2/mg dry weight-hour. The stria could not maintain constant respiration by relying solely upon endogenous fuel stores. With substrate supplied, the ATP level could be maintained at about 73% of that existing in vivo. Glucose appears to be an adequate substrate for stria in vitro since glutamate, pyruvate, and fumarate did not increase the respiratory rate. Succinate increased respiration markedly but did not increase the ATP level. Ouabain (10(-4) M) caused a 48% decrease in the respiratory rate. Incubation in Na+-free and K"-free medium, each resulted in irreversible decrease of respiratory rate comparable to (or greater than) that caused by ouabain. These data are in accord with the high activity of Na+-K+-ATPase in the stria and the pronounced sensitivity of the endolymphatic potential to ouabain.
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PMID:Respiratory rate and ATP content of stria vascularis of guinea pig in vitro. 71 73

The dermal cells in grey, xanthic, and white goldfish integuments were cytochemically characterized for the following enzymatic activities: tyrosinase, DOPA-oxidase, cytochrome oxidase, monoamine oxidase, peroxidase, non-specific esterase, cholinesterase, NAD-diaphorase, NADP-diaphorase, aryl sulfatase, nucleotide phosphodiesterase, beta-glucuronidase, acid phosphatase, alkaline phosphatase, adenosine triphosphatase, thiamine pyrophosphatase, glucose-6-phosphatase, aldolase, as well as succinate, malate, isocitrate, glutamate, glucose-6-phosphate, 6-phosphogluconate, alpha-glycerophosphate, alcohol, lactate, and beta-hydroxybutyrate dehydrogenases. It was found that the epidermis was a significant barrier to the access of cytochemical reaction substrates. Removal of the epidermal barrier provided dermal cell localizations of enzymatic activities which were reproducible. Further, alterations in reaction times and temperatures from the mammalian methodology provided conditions fe various integumental cells were compared for possible interrelationships. The basic foundations for future work with the dermis of poikilothermic vertebrates on an experimental basis were established. In addition, a previously undescribed non-pigmented dermal cell, the "x"-cell, was found to have enzymatic characteristics similar to both melanophores and lipophores. The "x"-cell may be the common precursor of both types of pigment cells.
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PMID:Cytochemical characterization of goldfish (Carassius auratus L.) dermis with special reference to the pigment cells. 82 86


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