Search results for "hydrophobic"
showing 10 items of 332 documents
Interactions of tetradecyldimethylaminoxide with polyacrylic and polymethacrylic acids in aqueous solution
2001
Abstract The interactions between the zwitterionic surfactant tetradecyldimethylaminoxide (C14DMAO) and the polyelectrolytes polyacrylic (PAA-205 and PAA-250) or polymethacrylic (PMA-100) acids have been investigated in aqueous solution. The physico-chemical properties of these systems have been monitored by measuring the solution pH, electric birefringence, zero-shear viscosity and density for increasing surfactant concentrations. The experimental results have shown that significant change in the physico-chemical properties of the polyacid/surfactant system occurs only in a narrow pH range and when the amphiphile forms rod-like micelles. Moreover, they clearly reveal the important role pla…
Behaviour of Nanomaterials in the Environment: A Study of Interaction between Humic Acids and Fullerene C60
2010
Interaction between buckminsterfullerene and humic substances of different origin was investigated using fluorescence spectrometry as function of concentration of humic substances, pH and ionic strength. Binding constants of humic substances and buckminsterfullerene were calculated. It can be suggested that the complexation was driven by hydrophobic interaction depending on properties of the interacting compounds. Hydrophobic interaction model was indicated by linear Stern–Volmer plot, and high Kd values characterized interaction between buckminsterfullerene and humic acids. The results of this study support the development of understanding of fate of nanomaterials in environment as well as…
Experiments Meet Hydrophobic Mismatch: A Re-evaluation Of The Orientation Of Model Transmembrane Peptides From Solid-State NMR
2009
The basic physical rules underlying the organization of biological membranes can be gathered under the simple, but powerful, concept of hydrophobic mismatch. For example, the mutual adjustment of the lipid and protein hydrophobic lengths can be related with the existence of lipid rafts and explain discrete secretory pathways in the Golgi apparatus. The orientation of membrane protein fragments is predicted to follow the same hydrophobic mismatch principles, as illustrated by some experiments and molecular dynamics simulations. However, this appears to be challenged by results of solid-state 2H NMR experiments on model transmembrane peptides, displaying tilt angle values unexpectedly small a…
Improved antifouling properties and selective biofunctionalization of stainless steel by employing heterobifunctional silane-polyethylene glycol over…
2016
AbstractA straightforward solution-based method to modify the biofunctionality of stainless steel (SS) using heterobifunctional silane-polyethylene glycol (silane-PEG) overlayers is reported. Reduced nonspecific biofouling of both proteins and bacteria onto SS and further selective biofunctionalization of the modified surface were achieved. According to photoelectron spectroscopy analyses, the silane-PEGs formed less than 10 Å thick overlayers with close to 90% surface coverage and reproducible chemical compositions. Consequently, the surfaces also became more hydrophilic, and the observed non-specific biofouling of proteins was reduced by approximately 70%. In addition, the attachment of E…
Plant virus cell-to-cell movement is not dependent on the transmembrane disposition of its movement protein
2009
ABSTRACT The cell-to-cell transport of plant viruses depends on one or more virus-encoded movement proteins (MPs). Some MPs are integral membrane proteins that interact with the membrane of the endoplasmic reticulum, but a detailed understanding of the interaction between MPs and biological membranes has been lacking. The cell-to-cell movement of the Prunus necrotic ringspot virus (PNRSV) is facilitated by a single MP of the 30K superfamily. Here, using a myriad of biochemical and biophysical approaches, we show that the PNRSV MP contains only one hydrophobic region (HR) that interacts with the membrane interface, as opposed to being a transmembrane protein. We also show that a proline resi…
Profile and molecular modeling of 3-(indole-3-yl)-4-(3,4,5-trimethoxyphenyl)-1 H-pyrrole-2,5-dione (1) as a highly selective VEGF-R2/3 inhibitor.
2006
We report on selectivity profiling of 1 in a panel of 20 protein kinases and molecular modeling indicating 1 to be highly active and selective for VEGF-R2/3. Sequence alignment analysis and detailed insights into the ATP binding pockets of targeted protein kinases from the panel result in a unique structural architecture of VEGF-R2 mainly caused by the hydrophobic pocket I, determining the molecular basis for activity and selectivity of 1.
About the relevance of anion-π interactions in water.
2021
Anion-π interactions are emerging as exotic features with potential applications in chemistry. In the last years, their relevance in living systems has been outlined, and so far there is no concluding significant evidence recognized about the participation of anion-π interactions in water because anion-π sensors contain large aromatic hydrophobic surfaces with limited solubility. By transforming a neutral heterocycle (for example quinoline) into its corresponding salt (quinolinium), we have been able to overcome these solubility issues, and new cationic water-soluble fluorophores have been prepared. Herein, we used N-alkylated heterocycles as π-acidic surfaces to shed light on the nature of…
Effect of ionization and the nature of the mobile phase in quantitative structure-retention relationship studies.
2005
Abstract The octanol–water distribution constant, commonly called partition coefficient, Po/w, is a parameter often retained as a measure of the hydrophobicity of a molecule. log Po/w, for a given molecule, can be conveniently evaluated constructing correlation lines between standard retention factor logarithms (log k) in reversed-phase liquid chromatography (RPLC) and standard log Po/w values. Many compounds of pharmaceutical interest can be quite hydrophobic and have, simultaneously, basic nitrogen atoms or acidic sulfur containing groups in their structure. This renders them ionizable. The hydrophobicity of the molecular drug form (Po/w value) is completely different from its ionic form …
Donnan equilibrium of ionic drugs in pH-dependent fixed charge membranes: theoretical modeling.
2002
Abstract We have studied theoretically the partition equilibrium of a cationic drug between an electrolyte solution and a membrane with pH-dependent fixed charges using an extended Donnan formalism. The aqueous solution within the fixed charge membrane is assumed to be in equilibrium with an external aqueous solution containing six ionic species: the cationic drug (DH + ), the salt cations (Na + and Ca 2+ ), the salt anion (Cl − ), and the hydrogen and hydroxide ions. In addition to these mobile species, the membrane solution may also contain four fixed species attached to the membrane chains: strongly acid sulfonic groups (SO 3 − ), weakly acid carboxylic groups in dissociated (COO − ) a…
Synthesis and biological evaluation of dehydroabietic acid derivatives.
2010
A series of C18-oxygenated derivatives of dehydroabietic acid were synthesized from commercial abietic acid and evaluated for their cytotoxic, antimycotic, and antiviral activities.