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)

For anaerobic glucose-limited chemostat cultures of Escherichia coli a value of 8.5 was found for YmaxATP. For anaerobic glucose- or ammoniumlimited chemostat cultures of the ATPase-negative mutant M2-6 of E. coli YmaxATP values of 17.6 and 20.0 were found, respectively. From these data it can be concluded that in the wild type during anaerobic growth 51-58% of the total ATP production is used for energetization of the membrane. Using the YATP values obtained in the anaerobic experiments a P/O ratio of 1.46 could be calculated for aerobic experiments with the wild type. It is concluded that from the energy obtained by respiration in wild type E. coli about 60% is used for membrane energetization and only about 40% for the actual formation of ATP. No dramatic difference in the maintenance requirement for ATP or glucose has been observed between glucose- and ammonium-limited chemostat cultures of the mutant. The large difference in maintenance requirement observed for such cultures of the wild type is therefore supposed to be made possible by ATP hydrolysis by the ATPase.
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PMID:A continuous culture study of an ATPase-negative mutant of Escherichia coli. 14 18

A new mutant strain of Escherichia coli in which phosphorylation is uncoupled from electron transport was isolated. The new mutant strain has a similar phenotype to the uncB mutant described previously; results from reconstitution experiments in vitro indicate that the new mutation also affects a component of the F0 portion of the Mg2+-stimulated adenosine triphosphatase. A method was developed to incorporate mutant unc alleles into plasmids. Partial diploid strains were prepared in which the uncB402 allele was incorporated into the plasmid and the new unc mutation into the chromosome, or vice versa. Complementation between the mutant unc alleles was indicated by growth on succinate, growth yields on glucose, ATP-dependent transhydrogenase activities, ATP-induced atebrin-fluorescence quenching and oxidative-phosphorylation measurements. The gene in which the new mutation occurs is therefore distinct from the uncB gene, and the mutant allele was designated uncC424.
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PMID:A mutation affecting a second component of the F0 portion of the magnesium ion-stimulated adenosine triphosphatase of Escherichia coli K12. The uncC424 allele. 14 27

Red blood cell plasma membranes contain a number of enzymes: ATPases, anion transport protein, glyceraldehyde 3-phosphate dehydrogenase, protein kinases, adenylate cyclase, acetylcholinesterase. Most of them are tightly bound to the membrane and are present in small amounts. As a result, structural characterization of erythrocyte membrane enzymes has not yet been successful. Functional studies have, however, yielded a great deal of information. ATPases allow active transport of cations (calcium, sodium, potassium). Anion transport protein controls movements of chloride and phosphate ions, and of glucose and water. Among glycolytic enzymes: glyceraldehyde 3-phosphate dehydrogenase is partially bound to the membrane. Protein kinases catalyze the phosphorylation of several membrane proteins, one of which (spectrin) is involved in red blood cell mechanical properties. The physiological role of adenylate cyclase is unknown. Acetylcholinesterase is an ectoenzyme. Calcium-dependent ATPase, adenylate cyclase and phosphorylation of erythrocyte membrane proteins have been found abnormal in various conditions: hereditary spherocytosis, sickle-cell anemia, progressive muscular dystrophies, all of these disorders being associated with a decreased deformability of the erythrocyte.
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PMID:The enzymes of the red blood cell plasma membrane. 14 25

The possible presence of hexokinase in basal lateral membranes from rat kidney proximal tubules was investigated. Basal lateral membranes were obtained from homogenates of rat kidney cortex by differential centrifugation and free flow electrophoresis. They were further purified by density gradient centrifugation. Hexokinase activity was measured as the phosphorylation of D-[U14C]glucose. Throughout the purification of the membranes, the specific activity of hexokinase decreased while that of (Na+ + K+)-ATPase increased. Hexokinase activity in all fractions could be quantitatively accounted for in terms of cytosolic and mitochondrial enzyme contributions. It is concluded that there is no hexokinase activity in basal lateral membranes from rat kidney.
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PMID:Is hexokinase present in the basal lateral membranes of rat kidney proximal tubular epithelial cells? 14 9

A new mutant strain of Escherichia coli in which phosphorylation is uncoupled from electron transport was isolated. A genetic-complementation analysis, using partial diploid strains, showed that the new mutant allele, uncD409, is in a gene distinct from the other previously identified genes uncA, uncB and uncC. A strain carrying the uncd409 allele has no Mg2+ ion-stimulated adenosine triphosphatase activity and is therefore phenotypically similar to strains carrying the uncA401 mutant allele. Complementation between the uncA401 and the uncD409 alleles occurred, as indicated by growth of partial diploid strains on succinate and their growth yields on limiting concentrations of glucose. Complementation was confirmed by using membranes prepared from the above partial diploids. Such membranes were found to have Mg2+-stimulated adenosine triphosphatase activity, ATP-dependent transhydrogenase activity ADP-induced atebrin-fluorescence quenching and low but significant amounts of oxidative phosphorylation.
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PMID:Genetic complementation between two mutant unc alleles (unc A401 and unc D409) affecting the Fl portion of the magnesium ion-stimulated adenosine triphosphatase of Escherichia coli K12. 14 75

We have previously reported on the isolation of a mutant strain of Escherichia coli, RF-7, that has a dicyclohexylcarbodiimide (DCCD)-resistant, membrane-associated adenosine triphosphatase (ATPase) activity (R. H. Fillingame, J. Bacteriol. 124:870--883, 1975). We report here that the DCCD resistance of the ATPase of this mutant varies significantly, depending upon the carbon source used for growth. When strain RF-7 was grown aerobically on either glycerol or glucose or anaerobically on glucose rather than on a combination of succinate, acetate, and malate, ATPase activity was more sensitive to inhibition by DCCD because the carbodiimide-reactive proteolipid reacted more readily with DCCD.
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PMID:Carbodiimide-resistant mutant of Escherichia coli: suppression of resistance to dicyclohexylcarbodiimide by growth on glucose or glycerol. 14 7

Mutant strains of Escherichia coli were isolated in which mutator (Mu) phage was inserted into various unc genes. Partial diploid strains were prepared from each of the Mu-induced unc mutants by using F-plasmids carrying mutations in one of the known unc genes (uncA, uncB, uncC, or uncD). The partial diploid strains and the corresponding segregant strains were examined for their ability to grow on succinate. The aerobic growth yields on limiting concentrations of glucose were also determined. Magnesium-stimulated adenosine triphosphatase activities, ATP-dependent transhydrogenase activities, and Atebrin fluorescence quenching activities were determined by using membrane preparations from each strain. Genetic complementation was assessed from the results obtained, and it was concluded that the four unc genes examined are part of a single transcriptional unit and that they are transcribed in the order uncBADC.
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PMID:Mu-induced polarity in the unc operon of Escherichia coli. 14 12

The relationship between lysozyme and sodium reabsorption by the kidney tubule was studied in the experimental Fanconi syndrome. Female, anesthetized Sprague-Dawley rats were injected intravenously with maleic acid (an inhibitor of sodium transport) neutralized with sodium hydroxide in doses of either 2 or 8 mmol/kg. Clearance studies were performed immediately afterward, and plasma and urine were analyzed for inulin, pH, sodium, glucose, and lysozyme. Two hours after the maleic acid injection, renal cortical tissue was removed and homogenized. Specific activity of Na-K-ATPase was assayed in the light microsomal fraction. The results showed that both concentrations of maleic acid caused significant increases in urinary volume, glucose excretion, and pH. There were significantly correlated decreases in TNafract and TLyfract. The slope of the regression line (TLyfract = 1.03 TNafract - 5.82; r = 0.92) approximated unity. Renal cortical Na-K-ATPase activity was significantly decreased by 25% in the animals receiving 2 mmol maleic acid and 43% in the animals receiving 8 mmol. The evidence suggests that lysozyme reabsorption in the proximal tubule might be mediated directly or indirectly by active tubular transport of sodium, a process that is related to the Na-K-ATPase transport system.
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PMID:Renal handling of lysozyme in experimental Fanconi syndrome. 14 77

Content of lactate, pyruvate as well as activity of hexokinase, phosphorylases, ATPase and transaminases were studied in dog and rat liver tissues under conditions of acute profuse hemorrhage and after its complete compensation by autogenic, isogenic blood and by sodium chloride 0.9% solution. Distinct inhibition of the hexokinase activity in the hemorrhage led to impairment of glucose utilization in liver tissue and to development of hyperglycemia. Alterations in arterial blood pressure correlated with the activity of tissue enzymes. Tissue metabolism was improved after compensation of blood losses by adequate amounts of blood at early period of hemorrhagic shock.
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PMID:[Liver metabolism during massive hemorrhage and subsequent blood transfusion]. 14 25

Plasma membranes from Candida tropicalis grown on glucose or hexadecane were isolated using a method based on the difference in surface charge of mitochondria and plasma membranes. After mechanical disruption of the cells, a fraction consisting of mitochondrial and plasma membrane vesicles was obtained by differential centrifugation. Subsequently the mitochondria were separated from the plasma membrane vesicles by aggregation of the mitochondria at a pH corresponding to their isoelectric point. Additional purification of the isolated plasma membrane vesicles was achieved by osmolysis. Surface charge densities of mitochondria and plasma membranes were determined and showed substrate-dependent differences. The isolated plasma membranes were morphologically characterized by electron microscopy and, as a marker enzyme, the activity of Mg2+-dependent ATPase was determine. By checking for three mitochondrial marker enzymes the plasma membrane fractions were estimated to be 94% pure with regard to mitochondrial contamination.
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PMID:Plasma membranes from Candida tropicalis grown on glucose or hexadecane. I. Isolation, identification and purification. 15 28


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