Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Vinyl Compounds”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,135 records · Page 63Linked to original sources
PubMedDate not supplied

Water-soluble dendrigrafts bearing saccharidic moieties: elaboration and application to enzyme linked OligoSorbent Assay (ELOSA) diagnostic tests.

The synthesis of a series of water-soluble galactopyranose-functionalized polystyrene-polyvinyl ether dendrigrafts and their characterization (in solution and thin solid deposits) have been achieved. The presence of external galactopyranose groups on dendritic polymers has been exploited to prepare dendrigraft-oligonucleotide conjugates using a simple one-step coupling procedure with amino-ended oligonucleotides (ODNs). Several parameters such as the peripherical density of hydrophilic branches, the polymerization degree of polystyrene or poly(hydroxyethyl vinyl ether) blocks, and the number of galactopyranose groups were tuned. A capture test with short labeled complementary ODNs (25 bases) confirmed the presence of covalently bound ODNs on various kinds of dendrigrafts. The ability of the dendritic polymers to enhance the sensitivity of enzyme-linked oligosorbent assay (ELOSA) diagnostic tests (detection of hepatitis B virus, DNA target of 2400 bases) was then evaluated, especially the influence of the macromolecular architecture and the impact of the structural parameters. The dendrigraft-ODN conjugate with the lower saccharide external density was found to lead to a very significant amplification of the fluorescence signal, corresponding to a limit of sensitivity of 10(9) DNA copies per milliliter (instead of 10(11) DNA copies per milliliter without using dendrigrafts). Conversely, the dendrigrafts exhibiting a very high number of branches and galactopyranose groups at their periphery were not able to induce a better sensitivity due to steric hindrance generated by the peripheral congestion on these polymers.

Dendrimers↗
PubMedDate not supplied

Temperature sensitization of liposomes by use of thermosensitive block copolymers synthesized by living cationic polymerization: effect of copolymer chain length.

We prepared block copolymers of (2-ethoxy)ethoxyethyl vinyl ether (EOEOVE) and octadecyl vinyl ether (ODVE) with the number average molecular weights of 6900, 9300, and 16 700 by living cationic polymerization. The poly(EOEOVE) block acts as a temperature-sensitive moiety, and the poly(ODVE) block acts as an anchor moiety. We also investigated the effect of chain length of the copolymer poly(EOEOVE) block on the ability to sensitize liposomes. The copolymers underwent a coil-globule transition at approximately 36 degrees C in the presence of a membrane of egg yolk phosphatidylcholine (EYPC), detected using differential scanning calorimetry (DSC). Liposomes encapsulating calcein, a water-soluble fluorescent dye, were prepared from mixtures of dioleoylphosphatidylethanolamine, EYPC, and the copolymers. While the copolymer-modified liposomes released little calcein below 30 degrees C, release was enhanced above 35 degrees C, indicating that dehydrated copolymer chains destabilized the liposome membrane. In addition, copolymers with a longer poly(EOEOVE) block induced a more drastic enhancement of contents release in a narrow temperature region near the transition temperature of the poly(EOEOVE) block. As a result, the copolymer with an average molecular weight of 16 700 generated highly sensitive liposomes that produced rapid and dramatic release of the contents in response to temperature.

Ethers↗
PubMed1994

Two-dimensional NMR characterization of the deoxymyoglobin heme pocket.

Traditionally, assigning the heme protein resonances has relied heavily on the comparison of spectra arising from protein reconstituted with specifically deuterated hemes and the native form. Such an approach can identify tentatively the broad, overlapping signals in the Fe(II) high-spin heme protein spectra. Although 2D NMR studies have reported alternative approaches to detect and assign paramagnetic signals, their effectiveness is limited primarily to Fe(III) low-spin systems and still depends upon isotopic labeling results to be definitive. For deoxymyoglobin, the reported 2D techniques have not produced any spin correlation maps. Nevertheless, our study demonstrates that the deoxymyoglobin spin correlations are indeed detectable and that a complete heme assignment, except for the meso protons, is achievable with only 2D NMR and saturation-transfer techniques. The 2D maps improve the spectral resolution dramatically and permit a comprehensive analysis of the deoxymyoglobin signals' temperature dependence, which supports the hypothesis that the electronic orbital ground state has contributions from both 5E and 5B2. The results also indicate a structural perturbation in the vicinity of the 2 vinyl group as the protein undergoes the transition from oxy- to deoxymyoglobin state and a significant contribution from zero field splitting. Moreover, saturation-transfer experiments show that NMR can observe directly oxygen binding kinetics.

Animals↗
PubMed1985

Identification of plasmalogen as the major phospholipid constituent of cardiac sarcoplasmic reticulum.

The phospholipid molecular species of canine myocardial sarcoplasmic reticulum were identified by fast atom bombardment mass spectrometry, reverse-phase high-performance liquid chromatography, and other conventional techniques. Cardiac sarcoplasmic reticulum contains 1.4 mumol of lipid Pi/mg of protein which is comprised of 53% plasmalogen. Cardiac sarcoplasmic reticulum ethanolamine glycerophospholipid contains 73% plasmalogen that is predominantly comprised of moieties with 18-carbon vinyl ethers at the sn-1 position and arachidonic acid at the sn-2 position. In contrast, canine skeletal muscle sarcoplasmic reticulum contains only 19% plasmalogen that is predominantly comprised of ethanolamine plasmalogen (78% of skeletal muscle sarcoplasmic reticulum ethanolamine glycerophospholipid) with arachidonic and docosatetraenoic acids at the sn-2 position. The possibility that tetraenoic ethanolamine plasmalogens in both cardiac and skeletal muscle sarcoplasmic reticulum facilitate calcium translocation by their propensity for adopting a hexagonal II conformation at physiologic temperatures is discussed.

Animals↗
PubMed1987

Deoxyhexanucleotide containing a vinyl chloride induced DNA lesion, 1,N6-ethenoadenine: synthesis, physical characterization, and incorporation into a duplex bacteriophage M13 genome as part of an amber codon.

Organic synthesis and recombinant DNA techniques have been used to situate a single 1,N6-ethenoadenine (epsilon Ade) DNA adduct at an amber codon in the genome of an M13mp19 phage derivative. The deoxyhexanucleotide d[GCT(epsilon A)GC] was chemically synthesized by the phosphotriester method. Mild nonaqueous conditions were employed for deprotection because of the unstable nature of the epsilon Ade adduct in aqueous basic milieu. Physical studies involving fluorescence, circular dichroism, and 1H NMR indicated epsilon Ade to be very efficiently stacked in the hexamer, especially with the 5'-thymine. Melting profile and circular dichroism studies provided evidence of the loss of base-pairing capabilities attendant with formation of the etheno ring. The modified hexanucleotide was incorporated into a six-base gap formed in the genome of an M13mp19 insertion mutant; the latter was constructed by blunt-end ligation of d(GCTAGC) in the center of the unique SmaI site of M13mp19. Phage of the insertion mutant, M13mp19-NheI, produced light blue plaques on SupE strains because of the introduced amber codon. Formation of a hybrid between the single-strand DNA (plus strand) of M13mp19-NheI with SmaI-linearized M13mp19 replicative form produced a heteroduplex with a six-base gap in the minus strand. The modified hexamer [5'-32P]d-[GCT(epsilon A)GC], after 5'-phosphorylation, was ligated into this gap by using bacteriophage T4 DNA ligase to generate a singly adducted genome with epsilon Ade at minus strand position 6274. Introduction of the radiolabel provided a useful marker for characterization of the singly adducted genome, and indeed the label appeared in the anticipated fragments when digested by several restriction endonucleases. Evidence that ligation occurred on both 5' and 3' sides of the oligonucleotide also was obtained. The adduct was introduced into a unique NheI site, and it was observed that this restriction endonuclease was able to cleave the adducted genome, albeit at a lower rate compared to unmodified DNA. The M13mp19-NheI genome containing epsilon Ade will be used as a probe for studying mutagenesis and repair of this DNA adduct in Escherichia coli.

Adenosine↗
PubMed1989

Resonance Raman assignment and evidence for noncoupling of individual 2- and 4-vinyl vibrational modes in a monomeric cyanomethemoglobin.

We have investigated the resonance Raman spectra of monomeric insect cyanomethemoglobins (CTT III and CTT IV) reconstituted with (1) protohemes IX selectively deuterated at the 4-vinyl as well as the 2,4-divinyls, (2) monovinyl-truncated hemes such as pemptoheme (2-hydrogen, 4-vinyl) and isopemptoheme (2-vinyl, 4-hydrogen), (3) symmetric hemes such as protoheme III (with 2- and 3-vinyls) and protoheme XIII (with 1- and 4-vinyls), and (4) hemes without 2- and 4-vinyls such as mesoheme IX, deuteroheme IX, 2,4-dimethyldeuteroheme IX, and 2,4-dibromodeuteroheme IX. Evidence is presented that the highly localized vinyl C = C stretching vibrations at the 2- and 4-positions of the heme in these cyanomet CTT hemoglobins are noncoupled and inequivalent; i.e., the 1631- and 1624-cm-1 lines have been assigned to 2-vinyl and 4-vinyl, respectively. The elimination of the 2-vinyl (in pemptoheme) or the 4-vinyl (in isopemptoheme) does not affect the C = C stretching frequency of the remaining vinyl. Furthermore, two low-frequency vinyl bending modes at 412 and 591 cm-1 exhibit greatly different resonance Raman intensities between 2-vinyl and 4-vinyl. The observed intensity at 412 cm-1 is primarily derived from 4-vinyl, whereas the 591-cm-1 line results exclusively from the 2-vinyl. Again, there is no significant coupling between 2-vinyl and 4-vinyl for these two bending modes.

Animals↗
PubMed1976

Mechanims of stimulation of in vitro protein synthesis by some copolymers of styrene, vinyluracil, and vinyladenine with maleic acid and acrylic acid.

Copolymers of vinyl bases with acrylic acid and styrene or 1-vinyluracil with maleic acid were found to stimulate in vitro polyphenylalanine synthesis using a system extracted from Escherichia coli MRE600. Poly(styrene-maleic acid) was found to inhibit a ribosomal bound ribonuclease. Poly(1-vinyluracil, maleic acid), poly(1-vinyluracil, acrylic acid), and poly(9-vinyladenine, acrylic acid) were not inhibitors of the ribosome bound ribonuclease. The potent (up to fivefold) stimulation by these three polymers is due to the action of the polymers to interfere with ribosomal bound inhibitory protein. A protein, removed by washing ribosomes with 1 M ammonium chloride, characterized by M.J. Miller, A. Niveleau, and A.J. Wahba ((1974) J. Biol. Chem. 249, 3803) has been described as a potent inhibitor of in vitro poly(U)-coded protein synthesis using extracts of Escherichia coli MRE 600.

Acrylates↗
PubMed1976

On the inhibitory activity of 4-vinyl analogues of pyridoxal: enzyme and cell culture studies.

Analogues of pyridoxal and of pyridoxal phosphate in which the 4-CHO group is replaced with CH = CH2 were synthesized and were found to be potent inhibitors of pyridoxal kinase and pyridoxine phosphate oxidase of rat liver. They also inhibited the growth of mouse Sarcoma 180 and mammary adenocarcinoma TA3 in cell culture. Saturation of the vinyl double bond, replacement of the 5-CH2OH with methyl, methylation of the phenolic hydroxyl, or conversion to the N-oxide resulted in diminution or loss of all these activities. Similarly, the introduction of a beta-methyl group into the vinyl analogues of pyridoxal reduced all these inhibitory activities. The 4-vinyl anatogue of pyridoxal was shown to be a substrate of pyridoxal kinase and the product a potent inhibitor of pyridoxine oxidase, competing with pyridoxal phosphate. The affinity of this phosphorylated pyridoxal analogue to some apoenzymes varied greatly, indicating striking differences among the cofactor binding sites of these enzymes. The growth inhibitory effects of these analogues on cells in culture correlated well with their effects on pyridoxal kinase and pyridoxine phosphate oxidase in cell-free systems.

Animals↗