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)

Cholesterol was studied in experiments in vitro for its effect on the activity of Na, K-ATPase of the synaptic brain membranes of rats and a crystalline preparation of glutamate dehydrogenase from the liver mitochondria of a bull. Cholesterol decreased the activity of the above enzymes. When blocking guanidine groups of arginine residues of Na, K-ATPase and glutamate dehydrogenase the inhibiting action of cholesterol was absent. The obtained data evidence for the possibility of a direct interaction of cholesterol with membrane enzymes as well as for the important significance of guanidine groups of arginine residues of proteins in the process.
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PMID:[The role of guanidine groups of arginine residues of Na, K-ATPase and glutamate dehydrogenase in an interaction with cholesterol]. 255 50

Two monoclonal antibodies (MAb I and IV) have been prepared which showed high and specific reactions towards bovine heart mitochondrial coupling factor B (FB). Both have been identified as sub-type IgG1 of mouse immunoglobulins. MAb I reacts with purified and functionally active FB, alkylated or oxidized forms of FB and even with peptides formed on digestion of FB with trypsin. When used together, MAb I and IV reacted with FB in immunoblots of normal and urea treated samples of mitochondria, submitochondrial particles, ammonia-EDTA extracted particles, and H+-ATPase. Both MAbs inhibited FB-stimulated ATP-dependent reverse electron flow activity when FB was incubated with the antibody either before or after its addition to FB-deficient AE-particles. Reactivity of MAb I towards FB declined upon exposure of FB to guanidine HC1 while reactivity of MAb IV remained unaltered.
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PMID:Monoclonal antibodies to mitochondrial coupling factor B. 257 11

Immunoassays of dnaA protein in extracts from five strains showed a rather constant abundance relative to cell mass, with a variation of 800-2100 molecules/cell; overproducing cells contained 100-fold that number. About half of the dnaA protein in wild type cells was solubilized by a lysis procedure. Within the insoluble fractions, dnaA protein was identified by its characteristic high-affinity binding of ATP. An improved, rapid procedure for purifying dnaA protein from overproducing cells appears to depend on its coprecipitation with phospholipids and depends on solubilization by guanidine HCl. The procedure, with a 5-fold increased yield, also eliminates a potent ATPase contaminant. Purified dnaA protein, unlike dnaB and dnaC proteins, binds to phospholipid vesicles as judged by analysis on sucrose gradient centrifugation.
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PMID:The dnaA protein of Escherichia coli. Abundance, improved purification, and membrane binding. 283 65

In the yeast Saccharomyces cerevisiae, the pma1 mutations confers vanadate-resistance to H+-ATPase activity when measured in isolated plasma membranes. In vivo, the growth of pma1 mutants is resistant to Dio-9, ethidium bromide and guanidine derivatives. This phenotype was used to map the pma1 mutation adjacent to LEU1 gene on chromosome VII. From a cosmid library of a wild-type Saccharomyces cerevisiae genome, a large 30 kb DNA fragment was isolated by complementation of a leu1-pma1 double mutant. A 5kb HindIII fragment was subcloned and it restored both Leu+ and Pma+ phenotypes after integrative transformation. The restriction map of the 5 kb HindIII fragment and Southern blot analysis reveal that the cloned fragment contains the entire structural gene for the plasma membrane ATPase and the 5' end of the adjacent LEU1 gene. The pma1 mutation conferring vanadate-resistance is thus located in the structural gene for the plasma membrane ATPase.
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PMID:Genetic and molecular mapping of the pma1 mutation conferring vanadate resistance to the plasma membrane ATPase from Saccharomyces cerevisiae. 288 23

Ca2+-ATPase molecules were labeled in intact sarcoplasmic reticulum (SR) vesicles, sequentially with a donor fluorophore, fluorescein-5'-isothiocyanate (FITC), and with an acceptor fluorophore, eosin-5'-isothiocyanate (EITC), each at a mole ratio of 0.25-0.5 mol/mol of ATPase. The resonance energy transfer was determined from the effect of acceptor on the intensity and lifetime of donor fluorescence. Due to structural similarities, the two dyes compete for the same site(s) on the Ca2+-ATPase, and under optimal conditions each ATPase molecule is labeled either with donor or acceptor fluorophore, but not with both. There is only slight labeling of phospholipids and other proteins in SR, even at concentrations of FITC or EITC higher than those used in the reported experiments. Efficient energy transfer was observed from the covalently bound FITC to EITC that is assumed to reflect interaction between ATPase molecules. Protein denaturing agents (8 M urea and 4 M guanidine) or nonsolubilizing concentrations of detergents (C12E8 or lysolecithin) abolish the energy transfer. These results are consistent with earlier observations that a large portion of the Ca2+-ATPase is present in oligomeric form in the native membrane. The technique is suitable for kinetic analysis of the effect of various treatments on the monomer-oligomer equilibrium of Ca2+-ATPase. A drawback of the method is that the labeled ATPase, although it retains conformational responses, is enzymatically inactive.
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PMID:Fluorescence energy transfer as an indicator of Ca2+-ATPase interactions in sarcoplasmic reticulum. 295 Sep 38

Inhibition of Na, K-ATPase in fractions of unpurified synaptosomes and of heavy microsomes from lumbar part of spinal cord was found in dynamics of botulinic intoxication of the C type in rats. Both competitive and noncompetitive types of inhibition of the enzymatic activity were found in kinetic studies. Inhibition of transport functions across biological membranes caused by botulinic toxin was shown to have a reversible character. The inhibition might be prevented within the early periods of botulinic intoxication by administration of serotonin and guanidine hydrochloride.
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PMID:[Changes in Na, K-ATPase activity in subcellular fractions of the lumbar region of the spinal cord in botulism and the possibility of their pharmacological correction]. 299 64

The accessibility of the tryptophans in dog kidney Na,K-ATPase was studied with the technique of quenching by acrylamide. By use of a modified Stern-Volmer equation, fa, the effective fraction of tryptophans most exposed to quencher, and Ka, the effective quenching constant, were calculated. The direct Stern-Volmer plots are nonlinear under nondenaturing conditions, indicating that the tryptophan residues are unequally accessible to quencher. Modified Stern-Volmer plots revealed marked differences in the exposure of tryptophans in the E1 and E2 states. In the presence of Na or ADP, ligands that stabilize E1, these plots curve downward, indicating that the in addition to buried (unquenched) tryptophans, there is a heterogeneous class of tryptophans. In the presence of K or ouabain, conditions that favor E2, the modified Stern-Volmer plots are linear, consistent with a homogeneous population of tryptophans. Treatment with chymotrypsin to block the E1 to E2 transition results in a new set of quenching parameters which are unchanged with Na or K. Even after detergent denaturation (1% sodium dodecyl sulfate for 30 min), Stern-Volmer plots are nonlinear, and a significant fraction of tryptophan residues remain inaccessible to quencher. Denaturation with urea or guanidine HCl plus dithiothreitol increases the fraction of quenchable fluorescence even more, but still a small fraction, about 7-13%, is buried. The observed changes in exposure of the tryptophan residues would seem to account for the differences in intrinsic fluorescence seen on adding K and Na to Na,K-ATPase. The present results provide new evidence that a significant rearrangement of amino acid residues results from the E1 to E2 transition. Furthermore, a region of the molecule is inaccessible even after denaturation; this may correspond to highly hydrophobic stretches that are normally buried in the membrane.
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PMID:Accessibility of tryptophan residues in Na,K-ATPase. 303 Oct 29

There is fairly general agreement that myosin isolated from rabbit skeletal muscle has a molecular weight of about 500,000. The higher values that have been reported apparently reflect protein aggregation related to the method of preparation. On the basis of present evidence, the myosin molecule has an elongate helical core of two f subunits (average weight about 215,000) that extend into a globular head region containing three g subunits (average weight about 20,000). Myosin may be dissociated into subunits by a number of methods. In 5 M guanidine, the myosin molecule is dissociated into f and g subunits, while at pH above 10, the g subunits are dissociated from the intact fibrous core of myosin. The dissociation of g subunits at pH 10 is accompanied by the loss of both ATPase activity and actin-binding capacity; however, the exact biological significance of the g subunits is presently uncertain. In preliminary studies, the f subunits appear to contain the sulfhydryl residues currently implicated in myosin ATPase, and there is some indication of allosteric regulation of enzymic activity.
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PMID:Subunits and their interactions. 422 26

1. The rates of translocation of oxaloacetate and l-malate into rat liver mitochondria were measured by a direct spectrophotometric assay. 2. Penetration obeyed Michaelis-Menten kinetics, and apparent K(m) values were 40mum for oxaloacetate and 0.13mm for l-malate. 3. Arrhenius plots of the temperature-dependence of rates of penetration gave activation energies of +10kcal./mole for oxaloacetate and +8kcal./mole for l-malate. 4. The translocation of both oxaloacetate and l-malate was competitively inhibited by d-malate, succinate, malonate, meso-tartrate, maleate and citraconate. The K(i) values of these inhibitors were similar for the penetration of both oxaloacetate and l-malate. 5. Rates of penetration were stimulated by NNN'N'-tetramethyl-p-phenylenediamine dihydrochloride plus ascorbate under aerobic conditions or by ATP under anaerobic conditions. 6. The energy-dependent stimulation of translocation was abolished by uncouplers of oxidative phosphorylation. Oligomycin A, aurovertin, octyl-guanidine and atractyloside prevented the stimulation by ATP, but did not inhibit the stimulation by NNN'N'-tetramethyl-p-phenylenediamine dihydrochloride plus ascorbate. 7. Mitochondria prepared in the presence of ethylene-dioxybis(ethyleneamino)tetra-acetic acid did not exhibit the energy-dependent translocation, but this could be restored by the addition of 50mum-calcium chloride. 8. Valinomycin or gramicidin plus potassium chloride enhanced the energy-dependent translocation of oxaloacetate and l-malate. 9. Addition of oxaloacetate stimulated the adenosine triphosphatase activity of the mitochondria, and the ratio of ;extra' oxaloacetate translocation to ;extra' adenosine triphosphatase activity was 1.6:1. 10. Possible mechanisms for the energy-dependent entry of oxaloacetate and l-malate into mitochondria are discussed in relation to the above results.
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PMID:Factors affecting the translocation of oxaloacetate and L-malate into rat liver mitochondria. 423 43

1. The absence of creatine was demonstrated enzymically in the hen's-egg yolk and in the albumin contrary to former reports. 2. A comparison of the results obtained by enzymic and colorimetric methods to measure creatine is presented. 3. Creatine phosphate was not detected in the yolk extracts. 4. The content of free arginine enzymically assayed was 15.7mumol in the yolk and 3.38mumol in the albumin. Arginine amounts to practically all of the guanidine compounds in the yolk and one-half of those in the albumin. 5. No glycine amidinotransferase activity was found in the egg-yolk homogenates. 6. The heart of the chick embryo does not receive creatine from the egg and the creatine kinase activity present in this organ starting from the 27th hour of incubation suggests that the enzyme is a constitutive one working probably as an adenosine triphosphatase in a way similar to the kinase isolated from rabbit skeletal muscle. 7. Liver glycine amidinotransferase activity appeared clearly after day 5 of incubation. The specific activity reached a maximum at day 12 and then declined; however, the activity per total mass of liver increased steadily during all the prenatal period. Concomitantly with this steady increase a rise in the creatine content of the whole embryo was observed. An analogous increasing relationship between total liver amidinotransferase activity and liver creatine content was also detected during the postnatal period. 8. Repression of amidinotransferase by creatine cannot be accepted as occurring under physiological conditions since an inverse relationship between the two parameters was not observed. 9. Repression of liver amidinotransferase is observed only when pharmacological concentrations of the exogenous creatine are present in the chick liver.
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PMID:Creatine regulation in the embryo and growing chick. 549 9


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