Electrostatic interaction membranes

Sugawara, M., Takekuma, Y., Yamada, H., Kobayashi, M., Iseki, K., Miyazaki, K., A general approach for the prediction of the intestinal absorption of drugs regression analysis using the physicochemical properties and drug-membrane electrostatic interaction, J. Pharm. Sci. 1998, 87, 960-966. 

Efficient extraction of proteins has been reported with reverse micellar liquid membrane systems, where the pores of the membrane are filled with the reverse micellar phase and the enzyme is extracted from the aqueous phase on one side of membrane while the back extraction into a second aqueous phase takes place at the other side. By this, both the forward and back extractions can be performed using one membrane module [132,208]. Armstrong and Li [209] confirmed the general trends observed in phase transfer using a glass diffusion cell with a reverse micellar liquid membrane. Electrostatic interactions and surfactant concentration affected the protein transfer into the organic membrane and... 

K. A General Approach for the Prediction of Intestinal Absorption of Drugs Regression Analysis Using the Physicochemical Properties and Drug-Membrane Electrostatic Interaction, J. Pharm. Sci. 87, 960-966 (1998). 

The interest in vesicles as models for cell biomembranes has led to much work on the interactions within and between lipid layers. The primary contributions to vesicle stability and curvature include those familiar to us already, the electrostatic interactions between charged head groups (Chapter V) and the van der Waals interaction between layers (Chapter VI). An additional force due to thermal fluctuations in membranes produces a steric repulsion between membranes known as the Helfrich or undulation interaction. This force has been quantified by Sackmann and co-workers using reflection interference contrast microscopy to monitor vesicles weakly adhering to a solid substrate [78]. Membrane fluctuation forces may influence the interactions between proteins embedded in them [79]. Finally, in balance with these forces, bending elasticity helps determine shape transitions [80], interactions between inclusions [81], aggregation of membrane junctions [82], and unbinding of pinched membranes [83]. Specific interactions between membrane embedded receptors add an additional complication to biomembrane behavior. These have been stud-... 

Hydrogen bonding and electrostatic interactions between the sample molecules and the phospholipid bilayer membranes are thought to play a key role in the transport of such solute molecules. When dilute 2% phospholipid in alkane is used in the artificial membrane [25,556], the effect of hydrogen bonding and electrostatic effects may be underestimated. We thus explored the effects of higher phospholipid content in alkane solutions. Egg and soy lecithins were selected for this purpose, since multicomponent mixtures such as model 11.0 are very costly, even at levels of 2% wt/vol in dodecane. The costs of components in 74% wt/vol (see below) levels would have been prohibitive. 

Hydrogen bonding and electrostatic interactions between the sample molecules and the phospholipid bilayer membranes are thought to play a key role in the transport of such molecules. When dilute 2% wt/vol phospholipid in alkane is used in the artificial membrane [15, 23], the effect of hydrogen bonding and electrostatic effects may be underestimated. 

In a lipid environment, van der Waals interactions become less specific. Electrostatic effects are enhanced up to 40-fold (according to Coulomb s law) due to the low dielectric constant, e s 2, of the hydrophobic core of membranes. As a result, weak electrostatic interactions, e.g., between the 71-electrons of an aromatic ring and a cation [51], may come into play. In addition, H-bond interactions, which can be considered as dipole-dipole interactions can also become relevant. 

Electron Transfer Type of Dehydrogenase Sensors To fabricate an enzyme sensor for fructose, we found that a molecular interface of polypyrrole was not sufficient to realize high sensitivity and stability. We thus incorporated mediators (ferricyanide and ferrocene) in the enzyme-interface for the effective and the most sensitive detection of fructose in two different ways (l) two step method first, a monolayer FDH was electrochemically adsorbed on the electrode surface by electrostatic interaction, then entrapment of mediator and electro-polymerization of pyrrole in thin membrane was simultaneously performed in a separate solution containing mediator and pyrrole, (2) one-step method co-immobilization of mediator and enzyme and polymerization of pyrrole was simultaneously done in a solution containing enzyme enzyme, mediator and pyrrole as illustrated in Fig.22. 

PDI contains a C-terminal tetrapeptide sequence known as the endoplasmic retention signal, KDEL. This anchor mediates the interaction between plasma membrane and membranes of the Golgi apparatus via a KDEL receptor. The PDI KDEL receptor complex is recycled back into the endoplasmic reticulum (Xiao et al., 1999). It is thought that a saturation of the retention mechanism results in the secretion of PDI which is deposited on the cell membrane and stabilized by electrostatic interactions (Terada et al, 1995). The secreted PDI is termed cell surface PDI (csPDI)... 

Hydrophobic and electrostatic properties of these lipopeptides show synergistic effects upon binding with membranes.1311 Due to the long stretch of basic amino acids the electrostatic interaction of the K-Ras4B peptide with negatively charged vesicles results in an approx. 103-fold increase in binding compared with a neutral membrane. 

The second class of stable membrane anchoring motives does not rely on electrostatic interactions but supports the first (often isoprenoid) hydrophobic modification by additional thioester formation with fatty acids (eg. the H- and N-isoforms of Ras or in the a subunits of heterotrimeric G-proteins) or a second isoprenoid moiety (eg. Rab proteins).1331... 

The powerful tool of molecular genetics allows the modification of each single amino add in the peptide chain of a protein, e.g. ddetion of side residues necessary for isoprenylation or palmitoylation1361 or introduction of additional charged amino acids for electrostatic interaction with the plasma membrane.1371 Even some artificial modifications can be introduced by means of recombinant enzymes as shown above. 

Electrostatic Interaction of Myristoylated Proteins with Membranes Simple Physics, Complicated Biology, D. Murray, N. Ben-Tal, B. Honig, S. McLaughlin, Structure 1997, 5, 985-989. 

Hertel, C., Terzi, E., Hauser, N., Jakob-Rotne, R., Seelig, J., and Kemp, J. A. (1997). Inhibition of the electrostatic interaction between beta-amyloid peptide and membranes prevents beta-amyloid-induced toxicity. Proc. Natl. Acad. Sd. USA 94, 9412-9416. 

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