L-a-Phosphatidylethanolamine

As the distance between electrode and interface is reduced, kinetic effects due to the lipid layer reducing the flux of bromine becomes measurable. Several types of lipids have been investigated and a barrier effect due to L-a-phosphatidylethanolamine distearoyl is reported. 

Lipids with L-a-phosphatidylethanolamine derivatives with spermidines 1,2-dipalmitoyl-pho sphatidy lethanolamido spermine(DPPES) (116) or L-a-phosphatidylcholine with phos-phonate diester (127,128). 

In a typical experiment, Israelachvili deposited monolayers of surfactants onto cleaved mica sheets, and evaluated the surface energies using the JKR equation. Fig. 11 contrasts results for mica coated with monolayers of (a) L-a-dipalmitoyl-phosphatidylethanolamine (DMPE) where j/a = = 27 mJ/m and (b) hexa-decyltrimethylammonium bromide (CTAB) where = 20 mJ/m and = 50 mJ/m. ... 

The visual pigment present in rods has been termed rhodopsin and consists of 11-m-retinal, a derivative of vitamin A1( and a lipoprotein called opsin. Recent evidence(43) suggests that in native rhodopsin the retinal chromo-phore is covalently bonded to a phosphatidylethanolamine residue of the lipid portion of opsin. The structure of 1 l-cis-retinal is as follows ... 

Figure 3.91. Surface shear viscosity (a) and dilational modulus (b) of DPPC (L-a-dipalm-itoylphosphatidylchollne) and DMPE (L-a-dimyristoyl phosphatidylethanolamine) mono-layers. Inset 7c[a ) curves. (Redrawn from Kragel et al.. loc clt.)...

L-a-Dioleoyl Phosphatidylethanolamine (DOPE), and 1,2-Dipalmitoyl-OT-Glycero-3-Phosphocholine (DPPC) were purchased from Avanti Polar Lipids. The chol-PEGjj was obtained in one step from the reaction of cholesteryl chloroformate and a-amino-co-methoxy-PEG. The luciferase encoding gene was obtained as reported (22). Picogreen was purchased from Molecular Probes, USA, Baftlomycin from Sigma, France, the BCA kit from Pierce and the luciferase kit from Promega. 

A. K. Menon V. L. Stevens. Phosphatidylethanolamine is the donor of the ethanolamine residue linking a glycosylphosphatidylinositol anchor to protein. J Biol Chem, 1992, 267, 15277-15280. 

Gems, D., Ferguson, C.J., Robertson, B.D., Nieves, R, Page, A.P., Blaxter, M.L. and Maizels, R.M. (1995) An abundant, trarav-spliced mRNA from Toxocara canis infective larvae encodes a 26-kDa protein with homology to phosphatidylethanolamine-binding proteins. Journal of Biological Chemistry 270,18157-18522. 

The correct ratio of lipid constituents is important to form stable liposomes. For instance, a reliable liposomal composition for encapsulating aqueous substances may contain molar ratios of lecithin cholesterol negatively charged phospholipid (e.g., phosphatidyl glycerol (PG)) of 0.9 1 0.1. A composition that is typical when an activated phosphatidylethanolamine (PE) derivative is included may contain molar ratios of phosphatidylcholine (PC) cholesterol PG derivatized PE of 8 10 1 1. Another typical composition using a maleimide derivative of PE without PG is PC male-imide-PE cholesterol of 85 15 50 (Friede et al., 1993). In general, to maintain membrane stability, the PE derivative should not exceed a concentration ratio of about l-10mol PE per lOOmol of total lipid. 

In the above subsection it was demonstrated that the inclusion of electrostatic interactions into the pressure-area-temperature equation of state provides a better fit to the observed equilibrium behavior than the model with two-dimensional neutral gas. Considering this fact, we would like to devote our attention now to the character of the lipid film under the dynamical, nonequilibrium conditions. In the following we shall describe the dynamical behavior of the phospholipid(l,2-dipalmitoyl-3-sn-phosphatidylethanolamines DPPE) thin films in the course of the compression and expansion cycles at air/water interface. 

Uckun, P.M., Schieven, G.L., Tuel-Ahlgren, L.M., Etihirdik, L, Myers, D.E., Ledhetter, J.A., and Song, C.W., 1993, Tyrosine phosphorylation is a mandatory proximal step in radiation induced activation of the protein kinase C signaling pathway in human B-lymphocyte precursors. Proc. Natl. Acad Sci. U.S.A. 90 252-256 Vance, D.E., Walkey, C.J., and Cui Z, 1997, Phosphatidylethanolamine N-methyltransferase from tiver. Biochim. Biophys. Acta 1318 142-150... 

---