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Hydrophilic Head (hydrophilic + head)

Distribution by Scientific Domains

Chemistry	50%

Selected Abstracts

Kinetics of the M-Intermediate in the Photocycle of Bacteriorhodopsin upon Chemical Modification with Surfactants

PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2010
Li-Kang Chu
The spectroscopic and kinetic studies of the interaction between bacteriorhodopsin in the M-intermediate and several surfactants (cetyl trimethyl ammonium bromide, dodecyl trimethyl ammonium bromide, diethylene glycol mono- n -hexyl ether, ethylene glycol mono- n -hexyl ether, sodium 1-decanesulfonate and sodium 1-heptanesulfonate) have been investigated using steady-state UV,VIS spectrometry and time-resolved absorption techniques. The steady-state spectral results show that bR retains its trimeric state. Time-resolved observations indicate that the rate of deprotonation of the protonated Schiff base increases in the presence of the cationic surfactants, whereas insignificant changes are observed in the neutral or anionic surfactants. The rate of the reprotonation of the Schiff base in the transition M , N is accelerated in anionic and neutral surfactants, but is decelerated in the presence of the cationic surfactants. Surfactants with a longer hydrocarbon tail have a greater effect on the kinetics when compared with surfactants having shorter hydrocarbon tails. The opposite effect is observed when the hydrophilic head of the surfactants contains opposite charges. These distinct kinetics are discussed in terms of the difference in the modified surface hydrophilicity of the bR and the possible protein configurational changes upon surfactant treatments. [source]

Iron oxide-based magnetic nanostructures bearing cytotoxic organosilicon molecules for drug delivery and therapy

APPLIED ORGANOMETALLIC CHEMISTRY, Issue 3 2010
Alla Zablotskaya
Abstract The results of our own investigation on synthesis, physico-chemical and biological study of iron oxide based magnetic nanoparticles bearing cytotoxic organosilicon molecules of choline and colamine analogues, as potential agents for antitumor therapy, are summarized. These molecules contain hydrophilic head and long lipophilic tails, which are able to deepen inside the first surfactant shell (oleic acid), forming bilayer membrane like structures. Such compositions have a great privilege possessing magnetic properties, which in some cases could be essential moment in targeted drug delivery. The methodological approach has been developed and applied to the preparation of water soluble single or mixed coated biologically active nanoparticles of different types. Copyright © 2010 John Wiley & Sons, Ltd. [source]

The structure of human aldose reductase bound to the inhibitor IDD384

ACTA CRYSTALLOGRAPHICA SECTION D, Issue 5 2000
Vito Calderone
The crystallographic structure of the complex between human aldose reductase (AR2) and one of its inhibitors, IDD384, has been solved at 1.7,Å resolution from crystals obtained at pH 5.0. This structure shows that the binding of the inhibitor's hydrophilic head to the catalytic residues Tyr48 and His110 differs from that found previously with porcine AR2. The difference is attributed to a change in the protonation state of the inhibitor (pKa = 4.52) when soaked with crystals of human (at pH 5.0) or pig lens AR2 (at pH 6.2). This work demonstrates how strongly the detailed binding of the inhibitor's polar head depends on its protonation state. [source]

Synthesis of polymerizable amphiphiles with critical packing parameters systematically varied,

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 7-8 2006
M. H. Li
Abstract In this paper the design and synthesis of a group of polymerizable amphiphiles with different ratios of the number of hydrophilic heads and the number of hydrophobic tails are reported. The head/tail number ratio could be viewed as an approximate equivalent of the critical packing parameter. The synthetic procedure was optimized to be extendable. The design is expected to furnish a robust library of polymerizable amphiphiles for formation and immobilization of surfactant phases. Copyright © 2006 John Wiley & Sons, Ltd. [source]