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

---

Query: EC:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Phospholipids were found to be a constant component of rat glomerular basement-membrane preparations. The concentration fell during preparation of basement membrane by sonication of whole glomeruli, but then remained constant despite continued sonication. The proportions of the individual phospholipids were different from those of whole renal tissue or of isolated glomeruli. The basement-membrane preparations had no (Na(+)+K(+))-activated adenosine triphosphatase activity, an enzyme that is bound to plasma membranes. The concentration of lipid P was decreased on exposure in vivo or in vitro to antiserum against basement membrane; 7 days after injection of antiserum there was a change in the phospholipid composition, with a relative increase in phosphatidylcholine and a decrease in sphingomyelin content. The metabolic turnover rate of the lipid P remaining in the membrane was normal, as determined by (32)P incorporation. The loss of phospholipid was associated with decreases in the relative concentrations of hydroxyproline, hydroxylysine and glycine, and relative increases in proline, lysine, serine, threonine and valine. Administration of aminonucleoside and daunomycin produced proteinuria but did not cause a decrease in lipid P. Anticollagen and anti-lymphocyte sera that attached to the basement membrane but failed to produce proteinuria, also failed to affect the phospholipid content.
...
PMID:Phospholipid of the rat glomerular basement membrane in experimental nephrosis. 426 92

Porcine brain myosin is a cytoplasmic protein similar to, but distinct from, its muscle counterpart. It has a high K+-ATPase activity at high ionic strength in EDTA and a low Mg+2-ATPase activity that is activated fivefold by either porcine brain or rabbit skeletal muscle actin. The molecule consists of three classes of subunits, with molecular weights of approximately 195,000 , 19,000, and 16,000. Brain myosin contains less glutamic acid, less lysine, and more threonine, serine, proline, and tyrosine than skeletal muscle myosin. The brain myosin extinction coefficient at 278 nm is 0.810 cm2/mg. Hydrodynamic studies yield an S020,w of 4.95S, a D020,w of 1.07 x 10(-7) cm2/s for brain myosin, and indicate that the molecules aggregate at high ionic strength. The molecular weight of the molecule, as calculated from extrapolation of D020,w/S20,w to zero concentration, is 444,000. The intrinsic viscosity of brain myosin is 0.191 ml/mg. These data are consistent with a highly asymmetric molecular species. Circular dichroism spectroscopy indicates that brain myosin is 58-60% alpha-helical in the presence of Ca+2 ions, and that removal of Ca+2 causes a small change in the spectrum.
...
PMID:Physical and enzymatic properties of myosin from porcine brain. 611 56

When the bovine mitochondrial F1-ATPase is inactivated with dicyclohexyl[14C]carbodiimide and then gel-filtered, from 2 to 3 g atoms of 14C are incorporated/mol of enzyme. Prior inactivation of the enzyme by the modification of an essential tyrosine residue with 4-chloro-7-nitrobenzofurazan, a reaction that can be reversed by thiols, does not affect the irreversible inactivation of the ATPase by dicyclohexyl[14C]carbodiimide. During the large scale modification of the F1-ATPase by dicyclohexyl[14C]carbodiimide which led to 70% inactivation, 1.9 g atoms of 14C were incorporated/mol of enzyme. Isolation of the alpha, beta, and gamma subunits from this large scale inactivation revealed that the gram atoms of 14C bound per mol of each of the subunits was: alpha, 0.04; beta, 0.56; and gamma, 0.04. The majority of the radioactivity in a cyanogen bromide digest of the 14C-labeled beta subunit was isolated in a fragment that has the following amino acid sequence: Glu-Leu-Ile-Asn-Asn-Val-Ala-Lys-Ala-His-Gly-Gly-Tyr-Ser-Val-Phe-Ala-Gly-Val-Gly -Glu-Arg-Thr-Arg-Glu-Gly-Asn-Asp-Leu-Tyr-Glu*-His-Met; where Glu* represents the N gamma-glutamyl derivative of dicyclohexyl[14C]urea.
...
PMID:Inactivation of the bovine mitochondrial F1-ATPase with dicyclohexyl[14C]carbodiimide leads to the modification of a specific glutamic acid residue in the beta subunit. 611 57

Absorption of threonine was accompanied by a distinct increase in total activity of Mg2+- and Na+, K+-ATPases in rat small intestine. Sodium fluoride inhibited completely the Na+, K+-ATPase activity. After administration of insulin, activity of Na+, K+-ATPase was increased 2-fold without loading with threonine, and it was increased 3.3-fold in the amino acid loading. Sodium fluoride activated Mg2+-ATPase, insulin did not affect the enzyme activity but the hormone decreased partially the inhibitory effect of sodium fluoride on Na+, K+-ATPase.
...
PMID:[Effect of fluoride and insulin on cation-dependent ATPase activity of the enterocytes during threonine absorption]. 612 44

Young rats were force-fed for 3 days a purified diet devoid of threonine and a number of aspects relating to RNA metabolism in the livers were studied. The findings in the livers of rats force-fed the threonine-devoid diet in comparison with those force-fed the complete diet were as follows: a) poly(A)-mRNA was increased in nuclei and in polyribosomes; b) DNA-dependent RNA polymerases I and II activities were increased; c) in vitro release of 14C-orotic acid labeled RNA from nuclei revealed that transport was unchanged and nucleoside triphosphatase activity of nuclear envelopes was unchanged; d) polyribosomes (total, free and membrane-bound) shifted toward heavier aggregation and in vitro 14C-leucine incorporation into protein was increased; e) RNase activities (at pH 5.4, 7.6, 9.5) were essentially unaltered; and f) in vivo 14C-choline incorporation into microsomal membranes was increased. By administering selected inhibitors of RNA and protein synthesis, such as actinomycin D, alpha-amanitin or cycloheximide, prior to killing the rats force-fed the threonine-devoid or complete diet for 3 days, it was demonstrated that the stimulatory effect on hepatic polyribosomes and protein synthesis in the experimental group was dependent upon new synthesis of poly(A)mRNA and of protein.
...
PMID:Studies dealing with hepatic RNA metabolism in rats force-fed a threonine-devoid diet. 616 Feb 24

The amino acid sequence of the proteolipid subunit of the ATP synthase was analyzed in six mutant strains from Escherichia coli K12, selected for their increased resistance towards the inhibitor N,N'-dicyclohexylcarbodiimide. All six inhibitor-resistant mutants were found to be altered at the same position of the proteolipid, namely at the isoleucine at residue 28. Two substitutions could be identified. In type I this residue was substituted by a valine resulting in a moderate decrease in sensitivity to dicyclohexylcarbodiimide. Type II contained a threonine residue at this position. Here a strong resistance was observed. These two amino acid substitutions did not influence functional properties of the ATPase complex. ATPase as well as ATP-dependent proton-translocating activities of mutant membranes were indistinguishable from the wild type. At elevated concentrations, dicyclohexylcarbodiimide still bound specifically to the aspartic acid at residue 61 of the mutant proteolipid as in the wild type, and thereby inhibited the activity of the ATPase complex. It is suggested that the residue 28 substituted in the resistant mutants interacts with dicyclohexylcarbodiimide during the reactions leading to the covalent attachment of the inhibitor to the aspartic acid at residue 61. This could indicate that these two residues are in close vicinity and would thus provide a first hint on the functional conformation of the proteolipid. Its polypeptide chain would have to fold back to bring together these two residues separated by a segment of 32 residues.
...
PMID:Identification of amino-acid substitutions in the proteolipid subunit of the ATP synthase from dicyclohexylcarbodiimide-resistant mutants of Escherichia coli. 625 67

Cultured chicken heart mesenchymal cells are proliferatively quiescent at low densities in medium containing plasma at 10%. Mitogenic hormones like epidermal growth factor and insulin-like growth factors cause these cells to proliferate very actively, as does infection with avian sarcoma viruses, erythroblastosis virus, or myelocytomatosis virus. We have found that the combination of phorbol 12-myristate 13-acetate (PMA), ionomycin or ouabain, and raised extracellular magnesium, likewise, causes these cells to proliferate very actively. Although these agents have no significant effect when acting singly, the combination of PMA at 100 ng/ml and 0.5 microM ionomycin induces a 6-fold increase in cell number at 4 days, and the combination of PMA, ionomycin, and 5.6 mM magnesium induces 12-fold multiplication. Likewise, PMA plus 1 microM ouabain induces 3-fold multiplication, whereas the combination of PMA, ouabain, and magnesium induces 6-fold multiplication. The tumor promoter PMA, like diacylglycerol released by breakdown of plasma membrane phosphatidylinositol diphosphate, is known to activate the serine- and threonine-specific intracellular enzyme kinase C. The divalent cation ionophore ionomycin is known to carry calcium into cells down an electrochemical gradient, and the Na+,K+-ATPase inhibitor ouabain appears to elevate intracellular calcium by means of a sodium-mediated exchange mechanism. Magnesium, like calcium, is known to enter cells passively down an electrochemical gradient and to be involved in the regulation of many key intracellular reactions. Our findings with PMA, ionotropes, and magnesium support a hypothesis that diacylglycerol-mediated activation of kinase C plus cellular divalent cation influx and/or mobilization, caused by the action of mitogenic hormones or the protein products of onc genes, are key events in the initiation of cell replication.
...
PMID:Phorbol 12-myristate 13-acetate, ionomycin or ouabain, and raised extracellular magnesium induce proliferation of chicken heart mesenchymal cells. 633 83

Procyclic culture forms of Trypanosoma brucei stock 427 have been screened for the presence of enzymes involved in glycolysis, mitochondrial energy metabolism and threonine degradation. The enzyme activities in the procyclics were compared with those of the blood stream forms. The specific activities of glycolytic enzymes represented 30-70% of the respective levels in the blood stream form, except for hexokinase which was 25-fold reduced. Cell fractionation showed that the enzymes involved in the early sequence of the glycolytic pathway, i.e. from hexokinase to phosphoglycerate kinase, and the enzymes NAD+-linked glycerol-3-phosphate dehydrogenase and glycerol kinase were all present in glycosomes equilibrating at a density of 1.23 g/cm3 in sucrose gradients. Malate dehydrogenase was 8-fold more active in procyclics than in bloodstream forms. This increase in activity was the result of the appearance of malate dehydrogenase in the glycosomes of the procyclics, in addition to mitochondrial and cell-sap activities which were present in both stages of the life cycle. Glycosomes contained part of the adenylate kinase activity, which was also associated with the mitochondrion. Succinate dehydrogenase and sn-glycerol-3-phosphate dehydrogenase, together with oligomycin-sensitive ATPase, were located in the mitochondrion which had a density in sucrose ranging from 1.16 to 1.18 g/cm3. This organelle also contained L-threonine 3-dehydrogenase and carnitine acetyltransferase, two enzymes involved in threonine catabolism. The latter two enzymes had activities which were, respectively, 15-and 13-fold higher in the procyclics than in the bloodstream form. Mitochondrial sn-glycerol-3-phosphate dehydrogenase was decreased 4-fold.
...
PMID:Localization of malate dehydrogenase, adenylate kinase and glycolytic enzymes in glycosomes and the threonine pathway in the mitochondrion of cultured procyclic trypomastigotes of Trypanosoma brucei. 680 9

Five peptide analogs of the actomyosin ATPase inhibitory region of troponin I (Tn-I) have been synthesized by the solid-phase method. One analog was constructed with a sequence identical to that found in species of Tn-I isolated from chicken fast, rabbit fast and rabbit slow skeletal muscle. A second peptide was made identical to the sequence of the homologous inhibitory region of Tn-I from rabbit cardiac muscle. The remaining three analogs were hybrids of the two sequences. We have verified that rabbit skeletal fast Tn-I was a better inhibitor than rabbit cardiac Tn-I in a rabbit skeletal actomyosin assay system and extended these studies to show that the same results were found in an assay system which used rabbit cardiac actomyosin. Our skeletal fast muscle peptide analog was also a better inhibitor in both assay systems than the cardiac Tn-I peptide analog. The hybrid peptides indicated that the changing of proline 110 to a threonine residue had no effect and suggested that position 110 was not essential to inhibition. The other amino acid change, the replacement of arginine 113 by a leucine residue, was shown to be the crucial difference and resulted in lower activity. Thus, th differences in relative inhibitory activity of rabbit skeletal fast and cardiac Tn-I can be at least partially and possibly solely explained by the single amino acid substitution at position 113. Short active sequences of proteins, like the Tn-I inhibitory region are potentially of enormous value as probes of structure-function relationships.
...
PMID:Comparative studies on the inhibitory region of selected species of troponin-I. The use of synthetic peptide analogs to probe structure-function relationships. 729 62

The substitution of arginine at position 210 in the alpha subunit of Escherichia coli F0F1-ATPase by either lysine or alanine causes dominance in complementation tests with a chromosomal c subunit mutation. Reversal of dominance was achieved for the alpha R210K mutation but not for the alpha R210A mutation by the presence of an aspartic acid residue at position 50 or at position 252 in the alpha subunit. It was concluded that position 210 in putative helix 4 of a previously proposed model of the alpha subunit is close to position 252 in putative helix 5 and to position 50 in putative helix 1. The juxtaposition of residues 252 and 210 was also indicated by the observation that the double mutant alpha R210Q/Q252R was partially functional. A revertant of the partially functional double mutant, isolated on succinate medium, was found to contain a third mutation resulting in Pro-204 in the alpha subunit being replaced by threonine. That the revertant phenotype was due to the alpha P204T change was confirmed by site-directed mutagenesis. ATP synthesis in the revertant strain was at near normal levels as judged by growth yield experiments, but the revertant strain was unable to pump protons in response to ATP hydrolysis.
...
PMID:The essential arginine residue at position 210 in the alpha subunit of the Escherichia coli ATP synthase can be transferred to position 252 with partial retention of activity. 749 77


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---