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  • Chemistry  (22)
  • γ-Glutamyltransferase  (3)
  • intestinal delivery  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Tailoring of macromolecule conjugates using reversed micelles as matrix microreactors (1990)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 191 (1990), S. 2801-2814 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Being solubilized in systems of reversed micelles of a surfactant, the macromolecules incorporate into the inner cavities of the micelles, whose size can be changed by varying the degree of hydration, w0 = [H2O]/[surfactant]. The conjugates of proteins (α-chymotrypsin, bovine serum albumin (BSA), monoclonal antibodies to insulin) with linear polyelectrolytes (poly(methacrylic acid), quaternized poly(4-vinylpyridine)) are synthesized in reversed micelles of Aerosol OT (sodium bis(2-ethylhexyl)sulfosuccinate) in the octane with 100% yield. The yield critically depends on the degree of hydration: the reaction does not proceed at low w0, but if w0 exceeds a threshold value (which differs for various macromolecules) the yield increases sharply and reaches 100%. Using the ultracentrifugation it was demonstrated that at low w0 the polyelectrolyte represents a compact globule compressed by the micellar matrix in the inner cavity of a micelle. Under these conditions, there is no space for the protein in a micelle which contains polyelectrolyte, and therefore reaction does not proceed. If w0 exceeds a threshold value the micelles become large enough to entrap the conjugated macromolecules simultaneously. The possibility of regulation of the conjugate composition by variation of w0 (via the size of the micellar matrix) was demonstrated by a conjugate of BSA with quaternized poly(4-vinylpyridine).
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1990.021911129
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  • 2
    Electronic Resource
    Electronic Resource
    DNA interpolyelectrolyte complexes as a tool for efficient cell transformation (1991)
    New York : Wiley-Blackwell
    Biopolymers 31 (1991), S. 1437-1443 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A tool was developed for enhancement of plasmid penetration into an intact cell, based on increasing DNA hydrophobicity via inclusion into a soluble interpolyelectrolyte complex (IPC) with polycations. The characteristics of formation of DNA IPC with synthetic polycations [poly(N-ethyl-4-vinylpyridinium)bromide (PVP) and PVP modified with 3% of N-cetyl-4-vinylpyridinium units (PVP-C)] were studied using ultracentrifugation and polyacrylamide gel electrophoresis methods. The conditions were established under which the mixing of DNA and polycation aqueous solutions results in the selfassembly of soluble IPC species. Incorporation of DNA into IPC results in the enhancement of DNA binding with isolated Bacillus subtilis membranes. A considerable increase in the efficiency of transformation of B. subtilis cells with pBC16 plasmid resulted from incorporation of the plasmid into the IPC with PVP and CVP.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360311210
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  • 3
    Electronic Resource
    Electronic Resource
    Subunit separation in reversed micelle system reveals the existence of active centers both on light and heavy γ-glutamyltransferase subunits
    Amsterdam : Elsevier
    FEBS Letters 295 (1991), S. 73-76 
    Details
    ISSN: 0014-5793
    Keywords: Micellar enzymology ; Protein subunit ; Reversed micelle ; Supra-macromolecular structure ; γ-Glutamyltransferase
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0014-5793(91)81388-O
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  • 4
    Electronic Resource
    Electronic Resource
    The principal difference in regulation of the catalytic activity of water-soluble and membrane forms of enzymes in reversed micelles - γ-Glutamyltransferase and aminopeptidase
    Amsterdam : Elsevier
    FEBS Letters 267 (1990), S. 236-238 
    Details
    ISSN: 0014-5793
    Keywords: Aminopeptidase ; Micellar enzymology ; Reversed micelle ; γ-Glutamyltransferase
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0014-5793(90)80933-A
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  • 5
    Electronic Resource
    Electronic Resource
    A new strategy for the study of oligomeric enzymes: γ-glutamyltransferase in reversed micelles of surfactants in organic solvents
    Amsterdam : Elsevier
    Biochimica et Biophysica Acta (BBA)/Protein Structure and Molecular 996 (1989), S. 147-152 
    Details
    ISSN: 0167-4838
    Keywords: Oligomeric enzyme ; Organic solvent ; Reversed micelle ; Surfactant ; γ-Glutamyltransferase
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0167-4838(89)90240-9
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  • 6
    Electronic Resource
    Electronic Resource
    Effects of Pluronic P85 Unimers and Micelles on Drug Permeability in Polarized BBMEC and Caco-2 Cells (1998)
    Springer
    Pharmaceutical research 15 (1998), S. 1525-1532 
    Details
    ISSN: 1573-904X
    Keywords: pluronic block copolymer ; intestinal delivery ; drug ; micelles ; blood brain barrier
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. Using polarized bovine brain microvessel endothelial cells (BBMEC) monolayers as in vitro model of the blood brain barrier and Caco-2 monolayers as a model of the intestinal epithelium, the present work investigates the effects of Pluronic P85 block copolymer (P85) on the transport of the P-gycoprotein (P-gp)- dependent probe, rhodamine 123 (R123). Methods. The permeability and cell efflux studies are performed with the confluent cell monolayers using Side-Bi-Side diffusion cells. Results. At concentrations below the critical micelle concentration, P85 inhibits P-gp efflux systems of the BBMEC and Caco-2 cell monolayers resulting in an increase in the apical to basolateral permeability of R123. In contrast, at high concentrations of P85 the drug incorporates into the micelles, enters the cells and is then recycled back out to the apical side resulting in decrease in Rl 23 transport across the cell monolayers. Apical to basolateral permeability of micelle-incorporated R123 in BBMEC monolayers was increased by prior conjugation of P85 with insulin, suggesting that modified micelles undergo receptor-mediated transcytosis. Conclusions. Pluronic block copolymers can increase membrane transport and transcellular permeability in brain microvessel endothelial cells and intestinal epithelium cells. This suggests that these block copolymers may be useful in designing formulations to increase brain and oral absorption of select drugs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1011942814300
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  • 7
    Electronic Resource
    Electronic Resource
    Effects of Pluronic Block Copolymers on Drug Absorption in Caco-2 Cell Monolayers (1998)
    Springer
    Pharmaceutical research 15 (1998), S. 850-855 
    Details
    ISSN: 1573-904X
    Keywords: block copolymer ; intestinal delivery ; drug ; micelles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. The present work characterizes the effects of Pluronic copolymers on the transport of a P-gp-dependent probe, rhodamine 123 (R123) in Caco-2 cell monolayers. Methods. The accumulation and efflux studies were performed on the confluent Caco-2 monolayers using fluorescent probes with and without Pluronic copolymers. Results. At concentrations below the critical micelle concentration single chains ("unimers”) of Pluronic P85 enhanced the accumulation and inhibited the efflux of R123 in Caco-2 monolayers. The transport of the P-gp-independent probe, rhodamine 110 was not altered under these conditions. In contrast the micelles increased R123 accumulation to a much lower extent when compared to the unimers and enhanced R123 efflux in Caco-2 monolayers. Conclusions. Pluronic P85 unimers increase accumulation of a P-gp-dependent drug in Caco-2 monolayers through inhibition of the P-gp efflux system. The mechanism of the micelle effect is not known, however, it is very similar to the micelle effects in BBMEC. This has been previously shown to involve vesicular transport of the micelle-incorporated drug. The study suggests that Pluronic copolymers can be useful in increasing oral absorption of select drugs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1011964213024
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  • 8
    Electronic Resource
    Electronic Resource
    Manipulation of Electric Charge on Vesicles by Means of Ionic Surfactants: Effects of Charge on Vesicle Mobility, Integrity, and Lipid Dynamics (1997)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 3 (1997), S. 690-695 
    Details
    ISSN: 0947-6539
    Keywords: liposomes ; phospholipids ; surfactants ; vesicles ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A combination of electrophoresis, dynamic light scattering, conductometry, and fluorescence spectroscopy was applied to investigate vesicles (both in the “solid” and “liquid” states) that had been imparted with electric charge through the incorporation of ionic amphiphiles. These amphiphilic compounds comprised cardiolipin (with two negative charges), sodium dodecyl sulfate (with one negative charge), and cetylpyridinium bromide (with one positive charge). By this means it was discovered that negative vesicles could be converted into neutral vesicles, and then into positive vesicles, by the addition of a cationic surfactant. The amount of cationic surfactant required for the conversion depended upon the mobility of the surfactant within the bilayer. Vesicles were found to be capable of absorbing large amounts of surfactant, both cationic and anionic, before ultimately disintegrating and releasing their contents. Mixtures of cationic and anionic vesicles were able to exchange surfactant, and thereby neutralize each other's charges, without any concurrent vesicle fusion. This phenomenon is reliable only if the vesicles are in the liquid state. Finally, a biphasic exchange process was observed in which a surfactant rapidly departs from one bilayer and then enters another, while a fluorescently labeled lipid travels the reverse path only slowly.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19970030507
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  • 9
    Electronic Resource
    Electronic Resource
    The synthesis and properties of several polypropargylpyridinium and polypropargylbipyridinium polyelectrolytes and their simple and complex tetracyanoquinodimethane ion-radical salts. I. Electrophysical properties (1975)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 19 (1975), S. 1275-1281 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Poly(propargylpyridinium chloride), poly(propargy1-4-vinylpyridinium chloride), poly(propargyl-2,2-bipyridinium chloride), poly(propargyl-1-methyl-2,2-bipyridinium methylsulfate chloride), poly(N-ethyl-vinylpyridinium bromide), and poly(propargyl-2-hydroxyquinolium chloride) were synthesized and a number of simple and complex, tetracyanoquinodimethane ionradical polyelectrolytes were prepared from them. An attempt was made to understand how the molecular structure of these compounds manifests itself in their observed electrophysical properties. Our results show increased electroconductivity in cases of simple and complex ion-radical polyelectrolytes where the conjugated bond polymer “backbone” is in close proximity to dipyridyl polarizing side groups.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1975.070190507
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  • 10
    Electronic Resource
    Electronic Resource
    Complex-forming polymeric sorbents with macromolecular arrangement favorable for ion sorption (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 24 (1979), S. 259-267 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Crosslinked polymeric sorbents with macromolecular arrangement favorable for sorption of copper ions have been obtained obtained on the base of copolymer of diethyl ester of vinylphosphonic acid with acrylic acid. The general principle involves interaction of linear polymer and sorbing ions in solution where the segments of the macromolecules are still mobile enough, subsequent fixation of optimal ion uptake conformations of macromolecules by crosslinking of metal polymer complexes, and removal of ions from crosslinked sorbent. Such treatment increases the exchange capacity of the sorbents more than twice and improves essentially its kinetic characteristics in comparison with the same copolymer crosslinked by conventional methods without special arrangement of macromolecules. The rate of the uptake on the sorbents with macromolecular arrangement favorable for ion sorption first increases with increase in the degree of crosslinking and then decreases. Apparently the jise of the crosslinking degree leads to more rigid fixation of the optimum ion uptake conformations of the macromolecules' segments. Further increase of the crosslinking degree alongside with fixation prevents ions from diffusion into the sorbent.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1979.070240123
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