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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An E. coli lysate after being gently washed to remove soluble components, supports replicative DNA synthesis, if soluble proteins and the deoxyribonucleotide triphosphates are added. This DNA synthesis is dependent on ATP and on the presence of the gene products of the dnaB, dnaG, and polC (DNA polymerase III) genes. It continues at the replication forks preformed in vivo and "Okazaki fragments" are intermediate products of the reaction. Two different methods were used to prepare the washed DNA containing fraction. The one method involves washing of a cell lysate situated on a dialysis membrane. The other method involves DNAase treatment of a lysate and sedimentation of the degraded DNA through a glycerol gradient. Both washed preparation contain not only the DNA and the replication forks but also functional amounts of DNA polymerase III and of the dnaB gene product. Other factors, that are essential for replicative DNA synthesis, including the dnaG gene product, are washed out of the DNA containing preparations and the system is reconstituted by readdition of the soluble proteins.
Mol Gen Genet 1976 May 07
PMID:Replication of E. coli duplex DNA in vitro. The separation of the DNA containing fractions of a lysate from the soluble enzymes and their complementation properties. 77 84

The kinetics of the affinity modification of phenylalanyl-tRNA synthetase from E. coli MRE-600 with chb-tRNA was used for investigation of copling between the binding sites of tRNA and other ligands. It was shown that ATP, phenylalanine and their mixture do not change the efficiency of complex formation but decrease specifically the rate of enzyme alkylation. L-Tyrosine and L-valine do not influence the enzyme alkylation. ATP is more effective protector than L-phenylalanine. In the presence of both ATP and phenylalanine the enzyme alkylation is excluded. The possibilities of this method for studying the coupling between binding sites are discussed.
Mol Biol (Mosk)
PMID:[Affinity modification of phenylalanyl-tRNA-synthetase in the presence of ligands]. 77 90

The reversible reaction catalyzed by ATP phosphoribosyltransferase favors the pyrophosphorolysis of phosphoribosyl-ATP (PR-ATP). The enzyme is inhibited by PR-ATP. To avoid this problem and measure with confidence initial rates of the transferase, we have purified more than one hundred fold the enzyme PR-ATP pyrophosphohydrolase, which irreversibly converts PR-ATP to PR-AMP. Using this coupled assay, we report on substrate kinetics and histidine inhibition studies of ATP phosphoribosyltransferase of Escherichia coli. 1. In the absence of histidine the variation of initial velocity as a function of ATP or phosphoribosyl pyrophosphate (PRPP) concentration, follows Michaelis-Menten kinetics, with ATP inhibiting at high concentrations. In the presence of histidine a change from hyperbolic to sigmoidal kinetics is observed. 2. Apparently AMP acts as a competitive inhibitor of ATP. 3. The bisubstrate kinetics gives a pattern of parallel lines, suggesting a double displacement mechanism. 4. The inhibition by histidine appears not to be cooperative or perhaps slightly negatively cooperative.
Mol Cell Biochem 1976 Jun 15
PMID:Kinetic properties of ATP phosphoribosyltransferase of Escherichia coli. 78 21

A protein kinase specific for casein and acidic ribosomal proteins was isolated and partly characterized. It was found that the enzyme utilizes GTP and ATP as phosphoryl donors. Its affinity for ATP was considerably higher than for GTP with the km values of 7.6 X 10(-6)M and 5.5 X 10(-5)M, respectively. Two-dimensional acrylamide gel electrophoresis revealed the phosphorylation of the same ribosomal proteins with either of the [gamma-32P] nucleotides used. It was also shown that one acidic protein (S1 or S2) of 40 S and two acidic proteins (L2 and L3) of 60 S ribosomal subunits were predominantly phosphorylated in vitro. The phosphorylated proteins: L2 and L3 seem to correspond to the proteins of L7 and L12 of E. coli ribosomes. The isolated kinase phosphorylated several basic ribosomal proteins though to a lower extent than the acidic ones.
Mol Biol Rep 1976 Nov
PMID:Ribosomal protein as substrate for a GTP-dependent protein kinase from yeast. 79 85

The enzymes involved in host-controlled modification and restriction by Bacillus subtilis strain N were detected in cell free extracts. In the presenct of Mg2+ the N-specific endonucleases cleaved unmodified DNA but did not attack phi-105C. N DNA carrying N-specific modification. The restriction endonuclease required neither SAM nor ATP for its activity. The N-specific modification enzyme was active only in the presence of SAM, indicating that modification in this syteem is a methylation of DNA.
Mol Gen Genet 1975 Jul 10
PMID:In vitro modification and restriction of phage phi-105c DNA with Bacillus subtilis N cell-free extract. 80 94

The metabolism of acid soluble adenine nucleotides in heat-synchronized Tetrahymena pyriformis GL has been studied. In addition, the effect of the synchronizing temperature (34 degrees C) on adenine nucleotide metabolism in heat-synchronized cells has been determined. In cells induced to divide synchronously through heat treatment (cyclic pulses of 34 degrees C for 30 min alternating with a 30 min recovery period at 28 degrees C) variations occurred in the levels of adenine nucleotides when samples of cells were analysed at the end of the last thermal period and at various time preceding the first synchronous cell division. The specific activities of the adenine nucleotides were found to be significantly higher during a pulse label period performed at the end of the last thermal period than at any time during the subsequent synchronous division cycle. The synchronizing temperature was found to partially deplete the intracellular stores at ATP in heat synchronized cells. This decrease was reversible with ATP levels recovering after 15 min of incubation at 28 degrees C. Fluctuations in the levels and specific activities of the adenine nucleotides are discussed in their relation to macromolecular synthesis and the cell cycle in Tetrahymena.
Mol Cell Biochem 1975 Jun 30
PMID:Adenine nucleotide metabolism in heat-synchronized Tetrahymena. 80 96

Treatment of growing cultures of Mycobacterium smegmatis with alkylating agents (methyl methanesulphonate, ethyl methanesulphonate, nitrogen mustard, or mitomycin C) or with ultraviolet light resulted in enhanced specific activities of a DNA polymerase and of an ATP-dependent deoxyribonuclease. Similar results had previously been obtained with hydroxyurea and with iron limitation. The three of these treatments which were tested (methyl methanesulphonate, mitomycin C and hydroxyurea) produced strand breaks or alkali-labile regions in the DNA of this organism. The increased enzyme activities could be prevented by simultaneous treatment with inhibitors of protein synthesis. In contrast, treatment of the cultures with intercalating agents (ethidium bromide, acridine orange, or proflavine), 5-fluorouracil, caffeine, or nalidixic acid, inhibited DNA synthesis without increasing the enzyme activities. These treatments did not produce strand breaks in the DNA of this organism. The results support the hypothesis that, in M. smegmatis, damage to DNA induces increased synthesis of enzymes associated with DNA repair.
Mol Gen Genet 1977 Feb 15
PMID:Increased DNA polymerase and ATP-dependent deoxyribonuclease activities following DNA damages in mycobacterium smegmatis. 84 85

Natural abundance carbon-13 and proton NMR spectra of bovine chromaffin granules have been obtained and analyzed using computer simulation techniques. High resolution spectra show the presence of a fluid aqueous phase containing epinephrine, ATP and a random coil protein. The protein spectrum contains unusually intense resonances due to glutamic acid and proline and has been simulated satisfactorily using the known amino acid composition of chromogranin A. The lipid phase of chromaffin granules gives rise to intense, but very broad, resonances in the carbon-13 spectrum. Protons in the lipid phase are also observable as a very rapid component of the proton-free induction decay (T2 approximately equal to 15 microns). Linewidths of the carbon-13 spectra have been used to set upper limits on rotational correlation times and on the motional anisotropy in the aqueous phase. These limits show that the aqueous phase is a simple solution (not a gel) that is isotropic over regions much larger than solute dimensions. No gel transition is observed between -3 and 25 degrees C. The carbon-13 spectra are definitely inconsistent with a lipoprotein matrix model and chromaffin granules previously proposed by Helle and Serck-Hanssen ((1975) Mol. Cell, Biochem. 6, 127-146). Relative carbon-13 intensities of ATP and epinephrine are not consistent with the known 1 : 4 mol ratio of these components. This fact suggests that epinephrine and ATP are not directly complexed in intact chromaffin granules.
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PMID:Analysis of the carbon-13 and proton NMR spectra of bovine chromaffin granules. 84 74

A method was developed for the introduction of [32p]Pi specifically into the beta-position of ATP and GTP. The method is based on two separate reactions involving (a) phosphorolysis of poly(A) or poly(G) [Soreq, Nudel, Salomon, Revel & Littauer (1974) J. Mol Biol. 88, 233-245] in the presence of [32P]Pi and (b) conversion of the labelled diphosphate into the corresponding triphosphate by transferring the active phosphate group from 1,3-diphosphoglycerate in a coupled reaction as decribed by Glynn & Chappell [(1964) Biochem. J. 90, 147-149]. Radioactivity in the beta- and gamma-phosphate groups of the labelled triphosphate was measured by using polynucleotide kinase. No detectable radioactivity was found in the gamma-phosphate group. The suitability of this method for the synthesis of other nucleoside triphosphates specifically labelled in the beta-position is discussed.
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PMID:A novel method for the synthesis of nucleoside triphosphates labelled with inorganic [32P]phosphate specifically in the beta-position. 85 33

1. The concentration of metabolites in intercostal and quadriceps muscle, and pulmonary function, were studied in twelve patients with chronic obstructive lung disease and acute respiratory failure before, during and after standardized treatment at an intensive care unit. The findings were compared with those obtained in hospitalized patients of comparable age with non-pulmonary diseases. 2. On admission, when the patients had marked hypoxaemia, hypercapnia and acidosis, the concentrations of ATP and creatine phosphate were low in both intercostal and quadriceps muscle, particularly the latter. The lactate concentration was increased in relation to control values but glycogen did not differ significantly. 3. In response to therapy, the Pa,CO2 and the patient's acidosis decreased, the vital capacity increased and lung mechanics improved along with the clinical condition. At the same time there were significant increases in the concentrations of ATP, creatine phosphate and glycogen in intercostal and quadriceps muscles, to values similar to, and for glycogen in excess of, those found in control subjects. Lactate concentration fell significantly during treatment. 4. In view of the low initial muscle concentrations of ATP and creatine phosphate in the patients, it is suggested that dysfunction of the respiratory muscles may be an important component of respiratory failure. Moreover, the concentration of energy-rich compounds in muscle rose significantly as the patients responded to treatment, which emphasizes the importance of adequate nutritional therapy in this disorder.
Clin Sci Mol Med 1977 Apr
PMID:Muscle metabolism in patients with chronic obstructive lung disease and acute respiratory failure. 86 35


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