Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.1.25 (triphosphatase)
 1,529 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A stable and homogeneous adenosine-5'-triphosphatase (ATPase, EC 3.6.1.3) has been solubilized from Rhodospirillum rubrum (R. rubrum) chromatophores by chloroform extraction. Purification of the Ca2+-dependent ATPase activity was 200-fold. Ca2+ can be replaced by Mg2+, Cd2+, and Mn2+. The Km for Ca-ATP (0.17 mM) is increased about 5-fold during solubilization of the enzyme, whereas the Km values for Mg-ATP (0.029 mM) and Cd-ATP (0.014 mM) are not affected. The chloroform-released ATPase has a molecular weight of 400,000 +/- 30,000 and consists of the following subunits (molecular weights in parenthesis): alpha(58,000), beta(53,500), gamma(39,000), delta(18,500), and epsilon(14,000). The amino acid composition and the fluorescence spectra are presented. Besides the chloroform-released ATPase complex three other Ca2+-dependent ATPase forms have been isolated from R. rubrum chromatophores by other methods for comparison. Ultrasonication of the membranes leads to the release of an ATPase complex which is mainly composed of alpha, beta, and gamma-subunits. From an acetone powder extract an ATPase complex could be purified by affinity chromatography which is composed of four kinds of subunits (alpha, beta, gamma, delta). The same acetone powder yields an ATPase consisting of only three different types of subunits (alpha, beta, gamma) if the final purification step is preparative disc electrophoresis on 6% polyacrylamide gels instead of affinity chromatography.
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PMID:Purification, subunit structure, and kinetics of the chloroform-released F1ATPase complex from Rhodospirillum rubrum and its comparison with F1ATPase forms isolated by other methods. 15 49

Chloroform enhances dose-dependently the number of preneoplastic foci in livers of weanling female Sprague-Dawley rats. The preneoplastic foci were induced with a single dose of 8 mg diethylnitrosamine (DEN)/kg body wt. Thereafter chloroform was applied twice weekly for 11 consecutive weeks in doses of 100, 200 and 400 mg/kg body wt, respectively. This treatment raised the number of adenosine-5'-triphosphatase (ATPase)-deficient foci up to 5-fold, that of gamma-glutamyltranspeptidase (GGTase) and glycogen-positive foci 13- and 10-fold, respectively, after 12 weeks; 25 mg caused no effect compared to DEN-treated controls. In contrast, daily doses of chloroform only, 200 and 400 mg/kg body wt for 33 days, and 800 mg/kg body wt for 20 days given to 3-4-week-old female Sprague-Dawley rats did not lead to island formation, measured after 12 weeks, indicating a promoting rather than an initiating potency.
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PMID:Dose-dependent promoting activity of chloroform in rat liver foci bioassay. 286 29

1. Ox-brain microsomes were incubated with [gamma-(32)P]ATP under various conditions. After the reaction, which was stopped with trichloroacetic acid, a small amount of phosphate remained bound to the washed precipitate. 2. Properties of the bound phosphate were studied by treatment with buffers and solvents. 3. The Na(+)-dependent increment in bound phosphate, predominant at low ATP concentration and features of which suggest involvement in the concomitant adenosine-triphosphatase activity, was rapidly released in both circumstances. 4. In aqueous media the labile phosphate was released entirely as inorganic phosphate at faster rates with increasing alkalinity. 5. In acidified chloroform-alcohol mixtures the released phosphate appeared both as inorganic phosphate and different single (32)P-labelled organic phosphates, which were tentatively identified as the relevant mono-alkyl phosphates, presumably derived by acid-catalysed alcoholysis of a labelled microsomal component, or components. 6. The labile phosphate corresponded to the P exchangeable with non-radioactive ATP added during the enzyme reaction. 7. The possible molecular nature of the labile fraction of the bound phosphate is discussed.
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PMID:Properties of phosphate bound to cerebral microsomes during adenosine-triphosphatase activity. 422 17

1. Polyribosomes and ribosomal subunits from rat liver were adsorbed on a cellulosic ion-exchange adsorbent, freeze-dried and extracted with organic solvents. The activity of extracted particles in peptide elongation was tested in the presence of purified peptideelongation factors. 2. Chloroform-methanol mixture (2:1, v/v) extracted 1.87+/-0.15 pmol of cholesteryl 14-methylhexadecanoate/pmol of the smaller ribosomal subunit and 0.92+/-0.11 pmol/pmol of the larger subunit. 3. In the presence of transferase I, extracted polyribosomes and 40S subunits bound more phenylalanyl-tRNA than did control non-extracted particles. The same binding as in control mixtures was obtained with extracted particles supplemented with cholesteryl 14-methylhexadecanoate in quantities corresponding to those extracted. 4. The polymerization of phenylalanine was greatly decreased with extracted polyribosomes and subunits and addition of the cholesteryl ester could not fully restore the original activity. 5. Extraction significantly decreased the activity of the P site of peptidyl transferase and normal activity was recovered after the addition of the ester. The A site of peptidyl transferase in extracted polyribosomes showed an increased activity when compared with non-extracted polyribosomes. 6. Cholesteryl 14-methylhexadecanoate apparently affects the function of the ribosomal A site and peptidyl transferase site and probably also that of the guanosine triphosphatase site and P site. The presence of different amounts of the ester in polyribosomes may be one of the mechanisms modulating peptide elongation at the ribosomal level.
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PMID:Influence of cholesteryl 14-methylhexadecanoate on some ribosomal functions required for peptide elongation. 459 29

A nonspecific nucleoside triphosphatase was partially purified from skin and cutaneous melanoma tumors from Sinclair swine using chloroform precipitation, hydrophobic, ion-exchange and affinity chromatography techniques. The enzyme was not stimulated by Na+, K+ or Mg2+ but it was inhibited by EDTA. The enzyme was not inhibited by quercetin, proflavin, azide or ovabain. The enzyme exhibited optimal activity over a pH range of 8-9 and the activation energy was 10.4 and 9.8 kcal/mol for dUTP and ATP, respectively. The apparent Km of the enzyme for dUTP and dTTP was approximately 20 mumol/l while the apparent Km for dATP, ATP, dCTP, CTP and UTP was in the range of 65-80 mumol/l.
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PMID:Purification and properties of a nucleoside triphosphatase from Sinclair swine. 609 41