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)

Yeast hexokinase A(ATP:D-hexose 6-phosphotransferase) is inactivated when incubated in the presence of xylose and ATPMg, or in the presence of D-lyxose in a reaction medium in which ATPMg is being continuously regenerated (phosphoenolpyruvate and pyruvate kinase). The inactivation is due to the phorphorylation of the protein. A linear relationship was observed between the inactivation and the incorporation of 32P from [gamma-32P] ATP. All hexokinase and ATPase activity of the enzyme is lost when one phosphoryl group is incorporated per enzyme subunit (molecular weight 51,000). The phosphoryl group is covalently bound by a ester linkage with a serine residue of the protein.
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PMID:Studies on the active site of yeast hexokinase. Specific phosphorylation of a serine residue induced by D-xylose and ATPMg. 0 82

Human skin fibroblasts, grown to confluency in the presence of 32P for random labelling of the phospholipids, showed upon 24 h incubation in the presence of either 8 mM L-serine or 4 mM ethanolamine an increased content of phosphatidylserine (150% of control cells) or phosphatidylethanolamine (116% of control cells), respectively. Concomitantly the phosphatidylcholine correspondingly decreased. Upon cell harvesting and gentle enzyme preparation the base-treated cells demonstrated a significantly higher unstimulated, fluoride- and thyrotropin-stimulated activity of adenylate cyclase. The activities of total ATPase, ouabain-sensitive ATPase, 5'-nucleotidase and gamma-glutamyltransferase remained unaltered. When subjecting enzyme preparations from fibroblasts to ultrasonication the activity of adenylate cyclase decreased progressively with energy applied, whereas the activities of the other enzymes were unaltered ((K+ + Na+)-ATPase, 5'-nucleotidase) or even increased (Mg2+-ATPase, gamma-glutamyltransferase). The results have a bearing upon the regulatory function of the phospholipid microenvironment of membrane-bound enzymes.
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PMID:The influence of changes in the phospholipid pattern of intact fibroblasts on the activities of four membrane-bound enzymes. 1 85

1. 5-Methyltetrahydrofolic acid transport was studied across everted sacs of rat jejunal segments from control and whole body X-irradiated (700 rad) rats at 10(-5)M concentrations (at which optimum transport occurs) at various pHs.2. The folate transport from mucosal to serosal compartment was inhibited by about 55% in irradiated rat at the pH of the intestinal chyme (6.5). Extraneous ATP in the incubation system could restore the defective transport of the irradiated intestine.3. The maximum folate transport which occurred at pH 4.0 was not adversely affected by whole body irradiation. An acidic, pH dependent, passive uptake of 5-methyltetrahydrofolic acid was observed.4. The normal absorption barrier of the small bowel was not disrupted by the acidification process as practically no uptake was observed with irradiated segments pretreated at pH 4.0 except in the presence of ATP.5. Leucine and serine transport at a zero concentration gradient indicated active transport mechanisms which were not affected by acidification. Their uptake was additively increased in the presence of glucose and ATP, further indicating that the normal physiology of the intestines was not affected by the acidification process.6. An intestinal mucosal cell surface ATPase was observed which was Mg(2+) dependent. It could hydrolyse solution phase ATP and thus generate the protons necessary for the acidification of a microenvironment where passive uptake of the neutral folate species could occur.7. The ATPase activity was inhibited about 90% by 50 mM-Na azide at pH 6.5. Below this concentration folate transport was also inhibited.8. Na azide did not inhibit folate transport at pH 4.0, suggesting that its inhibition of folate uptake at pH 6.5 is related to its inhibitory effect on ATPase, rather than on folate transport per se. ATPase activity was therefore essential for folate transport at the pH of the intestinal chyme.
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PMID:An ATPase dependent, radiosensitive acidic microclimate essential for intestinal folate absorption. 2 19

A membrane-bound ATPase detected in extracts of anaerobically grown Staphylococcus epidermidis was inhibited by a variety of compounds which inhibit ATPases in other organisms. Serine and 2-aminoisobutyric acid (AIB) were shown to enter the organism via the same transport system. The transport of AIB, the membrane potential and the transmembrane pH gradient were partially or completely abolished by the same inhibitors and also by uncoupling agents and lipid-soluble ions. It is proposed therefore that this ATPase generates and maintains an electrochemical gradient of protons across the cytoplasmic membrane of S. epidermidis capable of driving AIB uptake. Studies of AIB-induced proton movements suggested that AIB enters via a proton symport mechanism.
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PMID:Anaerobic transport of serine and 2-aminoisobutyric acid by Staphylococcus epidermidis. 3 23

The chemical properties of two highly purified preparations of (sodium + potassium)-activated adenosine triphosphatase (NaK ATPase) and their subunits have been compared. One preparation is derived from the rectal gland of the spiny dogfish shark, Squalus acanthias and the other preparation is derived from the electric organ of the electric eel, Electrophorus electricus. Ouabain binding and phosphorylation from [gamma-32-P]ATP for both enzymes ranged from 4000 to 4300 pmol per mg of protein. This gives a stoichiometry for ouabain binding and phosphorylation of 1:1 for both enzymes. The molar ratios of catalytic subunit to glycoprotein was 2:1 for both enzymes, suggesting a minimum molecular weight of 250, 000, which agrees with the molecular weight obtained by radiation inactivation. Assuming that only one of the two catalytic subunits is phosphorylated and binds ouabain per (sodium + potassium)-activated adenosine triphosphatase molecule the data on phosphorylation and ouabain binding also give a molecular weight of 250, 000. The data on phosphorylatiion, ouabain binding, subunit composition, and molecular weight based on radiaion inactivation are thus all internally consistent. A technique has been developed for isolation of pure catalytic subunit and glycoprotein in good yields by preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A variety of chemical studies have been carried out with the purified subunits. The amino acid composition of the catalytic subunit was different from that of the glycoprotein, but the amino acid composition of each of the two subunits was essentially the same for both species. However, the NH2-terminal amino acid for the catalytic subunit was alanine for the rectal gland enzyme and serine for the electric organ enzyme, suggesting some differencesin amino acid sequences for the two species. The NH2-terminal amino acid for the glycoprotein was alanine for the two species. The glycoproteins from both species contained the same carbohydrates but in quite differing amounts. The carbohydrates were glucosamine, sialic acid, fucose, galactose, mannose, and glucose. The release of all the sialic acid from the electric organ enzyme and the release of 40% of the sialic acid from the rectal gland enzyme did not affect (sodium + potassium)-activated adenosine triphosphatase activity. Both enzymes contained the following phospholipids, which accounted for 98 to 100% of the total phospholipid phosphorus: sphingomyelin, lecithin, phosphatidylserine, phosphatidylethanolamine, and phosphatidylinositol. With the exception of phosphatidylethanolamine, and phosphatidylinositol. With the exception of phosphatidylserine, the amount of any phospholipid per mg of enzyme as well as the total phospholipid content were quite different for the two enzymes.
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PMID:Molecular properties of purified (sodium + potassium)-activated adenosine triphosphatases and their subunits from the rectal gland of Squalus acanthias and the electric organ of Electrophorus electricus. 12 22

1. The uptakes of Pi and serine by whole cells of mutant strains of Escherichia coli K12, grown under both aerobic and anaerobic conditions, were studied. 2. Uptake by aerobic cells was low in a ubiquinone-less mutant but normal in two mutant strains unable to couple phosphorylation to electron transport. 3. One of these uncoupled strains, carrying the unc-405 allele, does not form a membrane-bound Mg2+-stimulated adenosine triphosphatase aggregate, and it is concluded that the Mg2+-stimulated adenosine triphosphatase does not serve a structural role in the aerobic active transport of Pi or serine. 4. The other uncoupled strain, in which aerobic uptake is unaffected, carries a mutation in the uncB gene, thus distinguishing this gene from the etc gene, previously shown to be concerned with the coupling of electron transport to active transport. 5. The uptakes of Pi and serine by anaerobic cells were normal in the ubiquinone-less mutant, but defective in both the uncoupled strains. 6. The uptake of Pi and serine by anaerobic cells of the uncB mutant could be increased by the addition of fumarate to the uptake medium. The unc-405 mutant, however, required the addition of fumarate for growth and for uptake. 7. The uncB mutant, unlike the unc-405 mutant, is able to grow anaerobically in a minimal medium with glucose as sole source of carbon. Similarly a strain carrying a mutation in the frd gene, which is the structural gene for the enzyme fumarate reductase, is able to grow anaerobically in a glucose-minimal medium. However, a mutant strain carrying mutations in both the uncB and frd genes resembles the unc-405 mutant in not being able to grow under these conditions.
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PMID:Metabolite transport in mutants of Escherichia coli K12 defective in electron transport and coupled phosphorylation. 12 86

The experiments described are based on the hypothesis that prolongation of the depressant action of ethanol leads to compensatory changes in neuronal membrane structures involved in impulse conduction and transmission, and that these become manifest as increased tolerance and withdrawal hyperexcitability. Behavioral tolerance was tested by means of the tilted plane test in rats consuming 9-10 g ethanol/kg/day in a liquid diet fed ad lib., or given 5 g/kg every other day by stomach tube, or doses rising from 6 to 9 g/kg/day maintaining continuous intoxication. All treatments were continued for about three or four weeks before testing. Rats consuming ethanol at a self-regulated rate did not develop tolerance, evidently because sufficient alcohol levels were not built up. Prolonged intoxication induced a high degree of tolerance and withdrawal symptoms, whereas intoxication every other day induced an intermediate degree of tolerance. When no definite abstinence symptoms were associated with the behavioral tolerance, cation stimulated ATPase activity of the brain microsomal fraction was not changed. With increasing withdrawal excitability, there was a relative increase in Na+, K+-stimulated ATPase and an decrease in Mg2+-stimulated ATPase whereas total activity of the enzyme system was not altered. 14C-serine was used as a precursor in order to detect changes in the metabolism of membrane components. So far, only acute experiments have been carried out in vivo. Heavy intoxication (6 g ethanol/kg by stomach tube) inhibited labeling of brain microsomal lipids and proteolipids. In "hangover", proteolipid labeling had returned to the control level whereas lipid labeling was still depressed. Cerebral cortex slices from rats in a withdrawal state after prolonged intoxication, and from control rats, were incubated in vitro with 14C-serine. Unstimulated tissue showed no effect of the prior treatment. When electrical stimulation was applied, much more activity was recovered in microsomal lipids of slices from withdrawal animals than from controls.
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PMID:Ethanol-induced changes in cation-stimulated adenosine triphosphatase activity and lipid-proteolipid labeling of brain microsomes. 12 37

Abnormalities have been noticed in the phospholipid and cholesterol composition of the atrophied gastrocnemius muscle of frog denervated for 1 month. Cholesterol : phospholipid molar ratios in the muscle increased on denervation. Sphingomyelin and cardiolipin fractions increased in contrast to phosphatidyl choline, phosphatidyl serine and phosphatidyl ethanolamine in the sarcoplasmic reticulum (SR) of denervated muscle. Na-azide sensitive Ca2+ ATPase activity of the mitochondria did not alter whereas that of SR decreased on denervation. Phospholipase C digestion impaired the organelle Ca2+-ATPase activity. The above abnormalities in enzyme activities have been correlated to the changes in the lipid composition of the denervated muscle. On the basis of these changes it is discussed that the primary change in the muscle due to denervation is the change in the permeability of the membrane.
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PMID:Ca2+-ATPase activity and lipid composition of sarcoplasmic reticulum of the gastrocnemius muscle of denervated frog. 12 20

A heat-stable protein has been detected in Saccharomyces cerevisiae which inhibits mitochondrial ATPase activity. The protein inhibitor has been isolated from extracts prepared by brief heat treatment of unbroken cell suspensions. The isolated inhibitor is a small basic protein (molecular weight close to 7000, isoelectric proint 9.05) devoid of tryptophan, tyrosine, and cysteine as well as proline. The NHP2-terminal amino acid is serine. The ultraviolet absorption spectrum shows the vibrational fine structure of the phenyl-alanine band. Like the ATPase inhibitor from bovine heart mitochondria the yeast inhibitor is rapidly destroyed by trypsin. It is also inactivated by the yeast proteinases A and B. Radioimmunological analysis indicates that the inhibitor is synthesized on cytoplasmic ribosomes. Its accumulation seems to be connected to the formation of the mitochondrial ATPase complex, since its specific activity is greatly reduced both in extracts obtained from the F1-ATPase-deficient nuclear mutant pet 936 and from the cytoplasmic petite mutant D 273-10B-1.
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PMID:A protein inhibitor of mitochondrial adenosine triphosphatase (F1) from Saccharomyces cerevisiae. 13 3

We described previously the existence of a soluble ATPase activity in rat liver mitochondria [1]. The purification and catalytic properties have been described [2]. In a continuation of these experiments, we have studied the immunologic and structural properties of one molecular form of this enzyme : ATPase I. We have prepared the antiserum anti-ATPase I and demonstrated the purity of our enzyme preparation by immunodiffusion and immunoelectrophoresis. An immunohistochemical method also confirmed the localization of ATPase I in the soluble fraction of mitochondria. The molecular weight of ATPase I was measured by G 100 Sephadex gel filtration and was found to be 18,400; electrophoresis on polyacrylamide gels gave a value of 18,600. The pHi of ATPase I was found to be 7,2. Amino acid analysis showed high amounts of aspartic acid, glutamic acid, serine and glycine. The molecular weight calculated from the total amino acid residues was found to be 17,000. Alanine is the NH2 terminal amino acid. The peptide maps obtained after degrading ATPase I with cyanogen bromide or trypsin are in accordance with the methionine, lysine and arginine residues we found in the ATPase I molecule. ATPase I does not appear to be a glycoprotein.
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PMID:Studies of soluble rat liver mitochondrial acid ATPases. II. Structural and immunological properties of ATPase 1. 15 69


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