Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Freshly harvested rat peritoneal mast cells were stained with different concentrations of acridine orange, a metachromatic fluorochrome known to form complexes with chromatin and muscopolysaccharides. Fluorescence metachromasia was observed in cytoplasmic granules in cell populations with intracelluar dye contents as low as 5 X 10(-16) mole per cell, one-half decade lower than required to produce metachromatic staining of the nucleus. Cytoplasmic granules did not stain uniformly throughout the cell; some granules exhibited red fluorescence and others green. As the amount of acridine orange uptake per cell was increased, cytoplasmic fluorescence became uniformly red and nuclear fluorescence gradually changed from green to yellow.
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PMID:Fluorescence microscopy of viable mast cells stained with different concentrations of acridine orange. 50 Apr 3

The 1 P+f phage, a virulent mutant of the moderate P+ phage for Bac. brevis var. G.-B., consists of a hexagonal head (90x90 nm) and a long non-contractile tail (340 nm). This phage is characterized by a relatively long latent period (90-110 min) and a low yield (40-50 particles per cell). The 1P+f phage is quite stable at pH values from 1 to 11, insensitive to osmotic shock, treatment with chloroform and acridine orange. The sensitivity of the phage to thermal treatment and UV-radiation has been studied. The nucleic acid of the P+f phage is double-stranded DNA of AT-type (GC equals 34.5 mole %) which contains 5-methylcytosine (0.18 mole %) and N6-methyladenine (0.32 mole%). The level of methylation of cytosine and adenine residues in DNA of the 1 P+f phage does not depend on the host studied (Bac. brevis, P- and S variants). The specificity of methylation of cytosine residues in the S and P- cells appears to be the same. DNA of the 1 P+f phage strongly differs from DNA of the host in nucleotide composition (GC equals 45.7 mole %). Nevertheless, phage DNA is very similar to DNA from Bac. subtilis in the character of pyrimidine distribution (the amount of different pyrimidine isopliths). This may testify to a somewhat common character of the nucleotide sequence organization in DNA of the phage and its host.
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PMID:[Some properties of 1 P+f bacteriophage for Bacillus brevis var. G.-B and its nucleic acid]. 121 2

Thymidylate synthase (5,10-methylenetetrahydrofolate:dUMP C-methyltransferase, EC 2.1.1.45) from methotrexate-resistant Streptococcus faecium has a UV absorbance peak at 259 nm and stains with acridine orange because of the presence of RNA on the protein. Material having an absorbance peak at 254 nm, obtained from the enzyme by phenol extraction, is degraded by treatment with pancreatic RNase, T1 RNase, and alkali but is stable to DNase. Dowex-1 chromatography of the pure enzyme yields two polynucleotide fragments in addition to the apoenzyme. As estimated from their absorbance, these fragments contain 4 and 11 mononucleotide residues per mole of enzyme, respectively. In crude extracts, thymidylate synthase is associated with rapidly sedimenting material that is sensitive to RNase. Treatment of crude extracts with RNase, as is done routinely during thymidylate synthase purification, most likely results in the formation of the small polynucleotides found on the enzyme. The RNA is not required for enzyme activity.
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PMID:Association of RNA with thymidylate synthase from methotrexate-resistant Streptococcus faecium. 618 21

Binding sites of Torpedo acetylcholinesterase (EC 3.1.1.7) for quaternary ligands were investigated by x-ray crystallography and photoaffinity labeling. Crystal structures of complexes with ligands were determined at 2.8-A resolution. In a complex with edrophonium, and quaternary nitrogen of the ligand interacts with the indole of Trp-84, and its m-hydroxyl displays bifurcated hydrogen bonding to two members of the catalytic triad, Ser-200 and His-440. In a complex with tacrine, the acridine is stacked against the indole of Trp-84. The bisquaternary ligand decamethonium is oriented along the narrow gorge leading to the active site; one quaternary group is apposed to the indole of Trp-84 and the other to that of Trp-279, near the top of the gorge. The only major conformational difference between the three complexes is in the orientation of the phenyl ring of Phe-330. In the decamethonium complex it lies parallel to the surface of the gorge; in the other two complexes it is positioned to make contact with the bound ligand. This close interaction was confirmed by photoaffinity labelling by the photosensitive probe 3H-labeled p-(N,N-dimethylamino)benzenediazonium fluoroborate, which labeled, predominantly, Phe-330 within the active site. Labeling of Trp-279 was also observed. One mole of label is incorporated per mole of AcChoEase inactivated, indicating that labeling of Trp-279 and that of Phe-330 are mutually exclusive. The structural and chemical data, together, show the important role of aromatic groups as binding sites for quaternary ligands, and they provide complementary evidence assigning Trp-84 and Phe-330 to the "anionic" subsite of the active site and Trp-279 to the "peripheral" anionic site.
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PMID:Quaternary ligand binding to aromatic residues in the active-site gorge of acetylcholinesterase. 841 49

Proline-rich peptides are known to adopt preferentially the extended polyproline II (PPII) helical conformation, which is involved in several protein-protein recognition events. By resorting to molecular modelling techniques, we wished to investigate the extent to which PPII helices could be used for the formation of isochelical peptide-DNA complexes leading to the selective recognition of the major groove of B-DNA. For that purpose, we have grafted to a cationic intercalator, 9-amino-acridine, an oligopeptide having the sequence: Pro- Arg-Pro-Pro-Arg-Pro-Pro-Arg-Pro-Pro-Asp-Pro-Pro. Each residue in the sequence was set in the D configuration, to prevent enzymatic hydrolysis, and each Arg residue was designed to target O6/N7 of a guanine base following the intercalation site. The Asp residue was designed to target a cytosine base, whilst simultaneously forming a bidentate complex with the Arg three residues upstream. Energy-minimization, using the JUMNA procedure, led to the following conclusions : 1) major groove binding is favoured over minor groove or exclusive binding to the phosphates by large energy differences, of over 50 and 90 kcal/mole, respectively: 2) the two best bound sequences are those having three successive guanine bases on the same DNA strand, immediately adjacent to the intercalation site. Sequence d(CGGGC G), encountered in the Primer Binding Site of the HIV retrovirus, thus ranks amongst the best-bound sequences; 3) replacement of an individual guanine amongst the three ones upstream of the intercalation site, by an adenine base, weakens by > 6 kcal/mole the binding energetics; 4) the conformational rigidity of the DNA-bound PPII helix should enable for a modulation of the base sequence selectivity, by appropriate replacements of the Arg and Asp residues. Thus sequence CGGCAAG, also encountered in the HIV genome, could be targeted by an oligopeptide having the sequence Pro-Arg-Pro-Pro-Asp-Pro-Pro-Asn-Pro-Pro-Asn-Pro-Pro-Arg-Ala.
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PMID:Can a polyproline II helical motif be used in the context of sequence-selective major groove recognition of B-DNA? A molecular modelling investigation. 891 63

The effect of temperature on the rate of proton transport and ATP hydrolysis by plasma membrane (PM) and tonoplast (TN) ATPases from barley (Hordeum vulgare L. cv CM 72) roots were compared. Rates of proton transport were estimated using the fluorescent amine dyes quinacrine and acridine orange. The ratio between rate of transport and ATP hydrolysis was found to depend on the dye, the temperature, and the type of membrane. The PM ATPase had an estimated Arrhenius energy of activation (Ea) of approximately 18 kilocalories per mole for ATP hydrolysis, and the Ea for proton transport was best estimated with acridine orange, which gave an Ea of 19 kilocalories per mole. The TN ATPase had an Ea for ATP hydrolysis of approximately 10 kilocalories per mole and the Ea for proton transport was best estimated with quinacrine, which gave an Ea of 10 kilocalories per mole. Acridine orange did not give an accurate estimate of Ea for the TN ATPase, nor did quinacrine for the PM ATPase. Reasons for the differences are discussed. Because it was suggested (AJ Pope, RA Leigh [1988] Plant Physiol 86: 1315-1322) that acridine orange interacts with anions to dissipate the pH gradient in TN vesicles, the complex effects of NO(3) (-) on the TN ATPase were also examined using acridine orange and quinacrine and membranes from oats and barley. Fluorescent amine dyes can be used to evaluate the effects of ions, substrates, inhibitors, and temperature on transport but caution is required in using rates of quench to make quantitative estimates of proton fluxes.
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PMID:Effect of temperature on the plasma membrane and tonoplast ATPases of barley roots : comparison of results obtained with acridine orange and quinacrine. 1666 16

Using pH-sensitive microelectrodes (in vitro) and acridine orange photometry (in vivo), the actions of the two tonoplast phosphatases, the tp-ATPase and the tp-PPase, were investigated with respect to how effectively they could generate a transtonoplast pH-gradient. Under standard conditions the vacuoles of the aquatic liverwort Riccia fluitans have an in vivo pH of 4.7 to 5.0. In isolated vacuoles a maximal vacuolar pH (pH(v)) of 4.74 +/- 0.1 is generated in the presence of 0.1 millimolar PP(i), but only 4.93 +/- 0.13 in the presence of 2.5 millimolar ATP. Both substrates added together approximate the value for PP(i). Cl(-)-stimulates the H(+)-transport driven by the tp-ATPase, but has no effect on the tp-PPase. The transport activity of the tp-ATPase approximates saturation kinetics (K((1/2)) approximately 0.5 millimolar), whereas transport by the tp-PPase yields an optimum around 0.1 millimolar PP(i). The transtonoplast pH-gradient is dissipated slowly by weak bases, from which a vacuolar buffer capacity of roughly 300 to 400 millimolar/pH(v) unit has been estimated. From the free energy (-11.42 kilojoules per mole) for the hydrolysis of PP(i) under the given experimental conditions, we conclude that the PPase-stoichiometry (transported H(+) per hydrolyzed substrate molecule) must be 1, and that in vivo this enzyme works as a H(+)-pump rather than as a pyrophosphate synthetase.
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PMID:Proton Gradient Across the Tonoplast of Riccia fluitans as a Result of the Joint Action of Two Electroenzymes. 1666 81

The conformational transitions of the alternating maleic acid copolymers with styrene (MA-St)n, and alpha-methyl styrene (MA-MSt)(n) in aqueous solutions were studied by means of various methods. The following results were obtained: 1) The conformational transitions of (MA-St)n from the compact to extended coil form are observed in various salt solutions, as in aqueous NaCl, and the compact form is stabilized by Rb+ and Cs+, but destabilized by Li+. The coions, Br-, I-, ClO4- and SCN- affect scarcely the stability of the compact form. 2) The temperature coefficient of viscosity d In [eta]/dT of (MA-St)n in 0.09 M NaCl was positive for the compact form, but negative for the coil form, and it reflects the transition. 3) The difference between specific heats for the compact and coil forms of (MA-St)n in 0.03 M NaCl is determined to be about 15% of the corresponding heat of transfer of benzene to aqueous medium. 4) A remarkable dilution of the bound monomeric acridine orange to the compact form (MA-St)n is observed and the dimerization free energy of the dye in the compact form is about -2.1 kcal mole at 25 degrees C. 5) Potentiometric, dilatometric and viscometric titrations of (MA-MSt)n in aqueous NaCl at 25 degrees C show a similar conformational transition to that of (MA-St)n. Also, the difference in the molar extinction coefficient at 261 nm indicates the transition. The compact form of (MA-MSt)n is more unstable than that of (MA-St)n. From the results, the compact conformations and the transition mechanism of both the polyacids were discussed in comparison with the results for the maleic acid copolymers with n-alkyl vinyl ethers.
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PMID:Conformational transitions of the hydrophobic polyacids. 1699 58

Capillary electrophoresis (CE) with postcolumn laser-induced fluorescence detection (LIF) was used to analyze single skeletal muscle fibers from young and old rats. Due to selective labeling of mitochondria with 10-N-nonyl acridine orange, the zeptomole (10(-21) mole) sensitivity, and the high separation power, three properties of individual mitochondrial particles were revealed: the number, the distributions of cardiolipin, and their electrophoretic mobilities. Type I fibers had more mitochondrial particles and cardiolipin per particle than did type IIb fibers from rats of similar age. Individual fibers of the same fiber type from young rats contained more mitochondrial particles and cardiolipin per particle than did fibers from old rats. There were fiber type-specific and age-specific differences in the electrophoretic mobility of individual mitochondrial particles. The CE-LIF results of individual mitochondrial particles are the first of their kind in that they reveal fiber type-specific and age-specific differences that are not obviously noticed in bulk measurements of heterogeneous tissues.
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PMID:Capillary electrophoresis reveals changes in individual mitochondrial particles associated with skeletal muscle fiber type and age. 1723 13