Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P20020 (adenosine triphosphatase)
 3,299 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Acute starvation of adult rats resulted in a rise in the electroconvulsive threshold at 48 hours (P less than .10) and at 72 hours (P less than .01), but not at 24 hours. Biochemical correlates included (1) ketonemia and mild hypoglycemia in the blood; (2) a significant rise in the brain cytoplasmic phosphorylation potential and in the energy charge potential; (3) a shift in the brain cytoplasmic oxidation-reduction potential to a more oxidized state; (4) probable partial inhibitions in brain phosphofructokinase and pyruvate dehydrogenase; and (5) relatively small increases in brain sodium (4.1%), potassium (2.4%), and chloride (4.3%). No major differences were seen in brain water content or adenosine triphosphatase activity. The observed cerebral biochemical alterations are believed to be the consequence of increased ketone body utilization, although the precise relationship to the alteration in the electroconvulsive threshold remains unclear.
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PMID:Starvation and seizures. Observation on the electroconvulsive threshold and cerebral metabolism of the starved adult rat. 12 78

Growth of Halobacterium halobium under illumination with limiting aeration induces bacteriorhodopsin formation and renders the cells capable of photophosphorylation. Cells depleted of endogenous reserves by a starvation treatment were used to investigate the means by which energy is coupled to the active transport of [14C]proline, -leucine, and -histidine. Proline was readily accumulated by irradiated cells under anaerobiosis even when the photophosphorylation was abolished by the adenosine triphosphatase inhibitor N,N'-dicyclohexylcarbodimiide (DCCD). The uptake of proline in the dark was limited except when the cells were allowed to accumulate adenosine 5'-triphosphate (ATP) by prior light exposure or by the oxidation of glycerol. DCCD inhibited this dark uptake. These findings essentially support Mitchell's chemiosmotic theory of active transport. The driving force is apparently the proton-motive force developed when protons are extruded from irradiated bacteriorhodopsin or by the dydrolysis of ATP by membrane adenosine triphosphatase. Carbonylcyanide m-chlorophenylhydrazone (CCCP), a proton permeant known to abolish membrane potential, was a strong inhibitor of proline uptake. Leucine transport was also apparently driven by proton-motive force, although its kinetic properties differed from the proline system. Histidine transport is apparently not a chemiosmotic system. Dark- or light-exposed cells show comparable initial rats of histidine uptake, and these processes were only partially inhibited by DCCD or CCCP. The histidine system apparently does not utilize ATP per se since comparable rates of uptake were exhibited by cells of differing intracellular ATP levels. Irradiated cells did effect a greater total accumulation of histidine than dark-exposed cells. These findings suggest that ATP is needed for sustained transport.
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PMID:Energy coupling in the active transport of amino acids by bacteriohodopsin-containing cells of Halobacterium holobium. 12 52

Comprehensive investigations were carried out for establishing the biological and nutritional value of low erucic-acid rapeseed oil from a variety of rape called Janpol selected in Poland. The pathophysiological effects of Janpol rapeseed oil were observed after giving it as the only source of fat in the diet or added in different proportions to other edible fats. In all cases the total amount of fat in the diet was 20 p. 100 kcal. The investigations were carried out on 78 young male Wistar rats aged 25 days at the beginning of the experiment. The rats were divided into 7 groups and they were given diets containing: 1) soybean oil; 2) mixed fats; 3) rapeseed oil of high erucic-acid content; 4) mixed fats containing 25 p. 100 of Janpol rapeseed oil; 5) mixed fats with 50 p. 100 of Janpol rapeseed oil; 6) mixed fats with 75 p. 100 of Janpol rapeseed oil; 7) Janpol rapeseed oil only. The experiment lasted 3 months. After its completion the rats were decapitated after 18 hours of starvation. The investigation s included : determination of weight gain, determination of the weight of selected organs (liver-lungs, heart, kidneys, testes, spleen), determination of alkaline phosphatase and pseudocholinesterase activity in the serum, determination of triglycerides and cholesterol in the serum, tests for adrenocortical function, histo-chemical investigations of the liver (alkaline and acid phosphatase, adenosine triphosphatase, fatty infiltration of the liver), macroscopic and microscopic anatomopathological examinations. The authors found the Janpol rapeseed oil caused less pronounced changes in the determined indices of the biological and nutritional evaluation as compared with high-erucic-acid rapeseed oil. Janpol repeseed oil given to experimental animals mixed with other fats in proportions of 25 p. 100 and 50 p. 100 of all fats in the diet, that is 5 p. 100 and 10 p. 100 kcal in the diet derived from Janpol oil gave in most determinations of the investigated parameters results very similar to those observed in animals receiving soybean oil. The results of these investigations show that Janpol rapesed oil can be used for nutrition of man in amounts not exceeding 10 p. 100 of the total caloric content of food.
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PMID:[Nutritional and biological experiences on low-erucic acid rapeseed oil "Janpol". Studies on rats after ingestion of "Janpol" oil and other edible fats]. 22 Sep

Amino acid transport was studied in C1 cells which contain amplified levels of sodium- and potassium-activated adenosine triphosphatase (Na,K-ATPase), in C4 cells which are ouabain-sensitive revertants, and in parental HeLa S3. Sodium-dependent uptake of aminoisobutyric acid and alanine was increased 2-fold in the amplified C1 cells. After a 6 h amino acid starvation period, the rate of sodium-dependent uptake of methylaminoisobutyric acid was 70-90% greater for C1 than for C4 and HeLa. This uptake was inhibitable by ouabain and the apparent Km values for high affinity uptake were similar in all three lines. Overall, neutral amino acid uptake through Systems A, ASC, and L was 2-fold higher in the Na,K-ATPase amplified C1 cells relative to C4 or HeLa. The induction of System A uptake of methylaminoisobutyric acid after starvation was more rapid in both the amplified C1 cells and the revertant C4 when compared to HeLa, which suggests that the selection for amplification of the Na,K-ATPase produced membrane alterations affecting the adaptive regulation of System A.
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PMID:Alterations in amino acid transport in Na,K-ATPase amplified HeLa cells. 300 Oct 56

The actomyosin protein complex of Physarum polycephalum was prepared from vegetative and starved plasmodia. The yield of actomyosin per unit wet wt. was the same from both types of plasmodia. Myosin was resolved from the complex by gel filtration and purified by ion-exchange chromatography. The Ca(2+)-stimulated adenosine triphosphatase activities of myosin preparations from vegetative and starved plasmodia were not appreciably different. Synthesis of myosin de novo was shown to occur during the starvation phase of the life-cycle by the isolation of labelled myosin preparations from plasmodia starved in the presence of [2-(14)C]glycine. Fractionation of polyacrylamide gels after gel filtration of labelled myosin confirmed the presence of label in the adenosine triphosphatase-active myosin band. It is concluded that during starvation myosin synthesis continues although there is a net loss of approx. 50% of the total protein. Sodium dodecyl sulphate-polyacrylamide-gel electrophoresis of Physarum myosin showed the presence of low-molecular-weight components of the molecule, similar to those of muscle myosins. The content and composition of the free amino acid pool of Physarum was measured at various time-intervals during the vegetative and starvation phases of the life-cycle.
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PMID:The biosynthesis of plasmodial myosin during starvation of Physarum polycephalum. 427 85

1. The intracellular location and maximal activities of enzymes involved in phosphoenolpyruvate synthesis have been investigated in pigeon liver. Enolase and pyruvate kinase were cytoplasmic, and the activities were 50-60 and 180-210mumoles/min./g. dry wt. at 25 degrees respectively. Phosphoenolpyruvate carboxykinase was present exclusively, and nucleoside diphosphokinase predominantly, in the mitochondria; the particles had to be disrupted to elicit maximal activities, which were 27-33 and 400-600mumoles/min./g. dry wt. at 25 degrees respectively. The activities of all four enzymes did not change significantly during 48hr. of starvation. 2. Conditions for incubation of washed isolated mitochondria were established, to give high rates of synthesis of phosphoenolpyruvate, linear with time and proportional to mitochondrial concentration. Inorganic phosphate and added adenine nucleotides were stimulatory, whereas added Mg(2+) inhibited, partly owing to activation of contaminant pyruvate kinase. Phosphoenolpyruvate formation occurred from oxaloacetate, malate, fumarate, succinate, alpha-oxoglutarate and citrate, in decreasing order of effectiveness. 3. The steady-state ATP/ADP ratio of mitochondrial suspensions was decreased in the presence of added 2.5mm-Mg(2+) (owing to stimulation of adenylate kinase and possibly of an adenosine triphosphatase), 0.5mm-Ca(2+) or 0.4mm-dinitrophenol. In each case the rate of substrate removal and oxygen uptake was increased, whereas phosphoenolpyruvate synthesis was inhibited. Citrate formation was enhanced, owing to de-inhibition of citrate synthase. These effects were not primarily related to changes in the oxaloacetate concentration. 4. Both phosphoenolpyruvate carboxykinase and nucleoside diphosphokinase were active within the atractylosidesensitive barrier to the mitochondrial metabolism of added adenine nucleotides. There was no correlation between the rate of substrate-level phosphorylation associated with the oxidation of alpha-oxoglutarate, and the synthesis of phosphoenolpyruvate. 5. The results suggest that phosphoenolpyruvate formation in pigeon-liver mitochondria is regulated partly by the phosphorylation state of the adenine and guanine nucleotides, and partly by variations in the oxaloacetate concentration, all in the mitochondrial matrix. 6. Phosphoenolpyruvate is assumed to be the metabolite transported from the mitochondria to the cytoplasm during gluconeogenesis from oxaloacetate in pigeon liver.
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PMID:The regulation of phosphoenolpyruvate synthesis in pigeon liver. 496 63

The increased rate of glucose uptake found in cells transformed by Rous sarcoma virus was shown to be enhanced relative to the changes in uptake induced in nontransformed cells by deprivation of glucose (deprivation derepression). Glucose-specific uptake sites were distinguished from glucose-galactose sites in nontransformed cells, and the capacities for glucose uptake and for galactose uptake were increased to about the same extent by the exclusion of glucose from the cell culture medium. Deprivation derepression occurred without a requirement for new RNA or protein synthesis, suggesting that preexisting inactivate uptake sites were activated. Deprivation derepression could be mimicked by the treatment of cells with adenosine triphosphatase activators, and adenosine triphosphate levels were reduced in glucose-deprived cells and in cells treated with adenosine triphosphatase activators. Cells transformed by the Bryan strain of Rous sarcoma virus were unresponsive to addition of high concentrations of glucose, to glucose starvation, or to treatment with adenosine triphosphatase activators, and the relative capacity for glucose uptake in these transformed cells was enhanced much more than the capacity of galactose uptake. It was concluded that cells infected by the Bryan strain of rous sarcoma virus in the process of transformation selectively synthesize more sites specific for glucose uptake. Lower levels of adenosine triphosphate found in transformed cells possibly contribute to a chronic derepression of uptake sites.
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PMID:Increased glucose uptake capacity of Rous-transformed cells and the relevance of deprivation derepression. 626 Mar 48

Ultracytochemical localization of adenosine triphosphatase (ATPase) activity in stigmas, pollens and pollen tubes of Fagopyrum esculentum was performed with the cytochemical method of lead phosphate precipitation. The results were as follows: (1) Lower activities of ATPase appeared in stigma cells at 0.5 hour after compatible and incompatible pollination. Stigma surface and pollen grains attached on stigma showed higher ATPase activities after compatible pollination and lower or no activities after incompatible pollination at 0.5 hour. ATPase localized on endoplasmic reticula and sperm cell in pollen grain. (2) Lower ATPase activities appeared both in stigma cells and pollen tubes in style at 1.5 hours after incompatible pollination. Pollen tube stopped growing and the degeneration of its cytoplasma began; on the contrary, at 1.5 hours after compatible pollination, higher ATPase activities were detected both in stigma cells and pollen tube in style. ATPase localized mainly on plasmolemma, in cytoplasmic matrix of stigma cells and in mitochondria, dictyosome, plastid envelop, and on the wall of pollen tube as well. The present study indicated that the stop of pollen tube growth after self-incompatibility of Fagopyrum esculentum resulted not only from the nutrient starvation of pollen tube, but also from its metabolic disorder in incompatible style.
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PMID:[The ultracytochemical localization of ATPase activity in pollen tube and stigma of Fagopyrum esculentum after compatible and incompatible pollination]. 1534 17

Activity of Na,K-ATPase (Na+,K+-adenosine triphosphatase, EC 3.6.3.9) in the whole erythrocytes was studied in dynamics of the complete rat alimentary starvation for 1, 3, 5, 7-8, and 10-12 days with water drinking ad libitum. There has been established a change of the erythrocyte Na,K-ATPase activity depending on the phase of starvation (the period connected with a certain level of metabolism). After the state on an empty stomach and adaptation to endogenous nutrition (the 0-I phase), from the 3rd to the 7-8th starvation day, the II phase, the period of compensated adaptation occurs (the euglycemia is preserved, the plateau level is preserved, the plateau level is achieved for protein loss and hormonal stimulation). Changes of the Na,K-ATPase activity level within the limits of the II phase were insignificant (p < 0.05), but loses of potassium content in plasma and erythrocytes have been from the 5th starvation day. The III phase (the 12-13th day) is the beginning of the terminal period and is characterized by a decrease of the Na,K-ATPase activity (the oubain-sensitive activity) and of Mg2+-ATPase (the oubain-independent activity), by a decrease of the plasma sodium level (prior to that, this level remained practically unchanged). Ad causes of the revealed decrease of the ATPase activities at the long-term starvation, there are considered aging of population of circulating erythrocytes (the absence of reticulocytes and young erythrocytes), depletion of cell energetic resources (hypoglycemia and glycopenia), effect of endogenous oubain, and endotoxemia.
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PMID:[Na,K-ATPase activity of erythrocytes of rats during prolonged starvation]. 2378

The mechanistic target of rapamycin complex 1 (mTORC1) protein kinase is a master growth regulator that responds to multiple environmental cues. Amino acids stimulate, in a Rag-, Ragulator-, and vacuolar adenosine triphosphatase-dependent fashion, the translocation of mTORC1 to the lysosomal surface, where it interacts with its activator Rheb. Here, we identify SLC38A9, an uncharacterized protein with sequence similarity to amino acid transporters, as a lysosomal transmembrane protein that interacts with the Rag guanosine triphosphatases (GTPases) and Ragulator in an amino acid-sensitive fashion. SLC38A9 transports arginine with a high Michaelis constant, and loss of SLC38A9 represses mTORC1 activation by amino acids, particularly arginine. Overexpression of SLC38A9 or just its Ragulator-binding domain makes mTORC1 signaling insensitive to amino acid starvation but not to Rag activity. Thus, SLC38A9 functions upstream of the Rag GTPases and is an excellent candidate for being an arginine sensor for the mTORC1 pathway.
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PMID:Metabolism. Lysosomal amino acid transporter SLC38A9 signals arginine sufficiency to mTORC1. 2557 8


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