L-a-Phosphatidylcholine

The majority of CYP enzymes are located in a hydrophobic environment in the endoplasmic reticulum of cells, although cytosolic enzymes also exist, such as CYP101. In order to mimic the physiological environment of CYP enzymes, a number of groups have used phospholipids to construct biosensors such as DDAB, dimeristoyl-L-a-phosphatidylcholine (DMPC), dilauroylphosphatidylethanolamine (DLPE) and distearoylphosphatidylethanolamine (DSPE). Phospholipid layers form stable vesicular dispersions that bear structural relationship with the phospholipid components of biologically important membranes. By this way a membranous environment is created that facilitates electron transfer between the enzyme s redox center and the electrode. 

Grigoriev, E. V., Pellerito, L., Yashina, N. S., Pellerito, C. and Petrosyan, V. S. (2000). Organotin(IV) chloride complexes with phosphocholine and dimyristoyl-L-a-phosphatidylcholine, Appl. Organomet. Chem., 14, 443-448. 

We have demonstrated that a chiral vesicle composed of di-palmitoyl-L- a-phosphatidylcholine(l-DPPC) doped with the azobenzene containing amphiphiles shown in Scheme 2 is a subject to photochemically triggered phase transition and exhibits a non-linear photoresponse in terms of ICD appearing at the absorption band of azobenzene. 

V-octadecyl)amino-naphthalene-6-sulfonic acid, sodium salt. 7 3-palmitoyl-2-(l-pyrenedecanoyl)-L-a-phosphatidylcholine. 

Fig. 6 Separation of (1) salicylic acid, (2) acetylsalicylic acid, (3) sulfasalazine, and (4) warfarin by use of capillary electrophoresis with pseudostationary egg L-a-phosphatidylcholine liposomes (29 mM phospholipid) in a polyacrylamide-coated capillary (100-/j,m I.D., 25 cm) at pH 7.4. Peak heights 0.02-0.04 absorbance units at 225 nm. (Reprinted with permission, with slight modification, from Ref. 32. Copyright 1995 VCH Verlagsgesellschaft.)...

Isooctane, AOT and HAuCl4-3H20 were acquired from Sigma-Aldrich, lecithin (L-a-phosphatidylcholine, 95% Plant Soy) from Avanti Polar lipids. 

In initial work, L- a-phosphatidylcholine (lecithin) from egg yolk was selected as the phospholipid, and later studies compared other phospholipids and lipid extracts from meat. As the study originated from investigations of cooked meat flavor, the model system reactions were carried out in aqueous solution buffered with phosphate at an initial pH of 5.7 and concentrations of the reactants were selected to approximate their relative compositions in mammalian muscle. The reactions were carried out under pressure... 

An aqueous solution of insulin is added to a solution of PLGA in methylene chloride. Additives,such as L-a-phosphatidylcholine dipalmitoyl, are included... 

Na caprate (Cio), Na laurate (C12), oleic acid Didecanoyl-L-a-phosphatidylcholine (DPPC), lyso PC Carbenoxolone, glycyrrhizinate... 

Chemicals L-a-phosphatidylcholine (Soy PC), 1,2-Dioleoyl-3-trimethylammonium-propane chloride salt (DOTAP), Polyethylene glycol 3350, Mg-ATP, trehalose (Avanti Polar Lipids, Alabaster, AL), Hanks Salt solution, Na HPO, KH PO, and carboxyfluorescein (Sigma-Aldrich, St. Louis, MO). 

The initial formulation consisted of soy derived 95% L-a-phosphatidylcholine (Soy PC) and l,2-Dioleoyl-3-Trimethy-lammonium-Propane Chloride Salt (DOTAP) at a 50 1 molar ratio, respectively. 

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). 

PLGA (D,L)-poly(lactic glycolic acid), PEG poly(ethylene glycol), DSPC distearoyl-L-a-phosphatidylcholine, DSPG distearoyl-L-a-phosphatidylglycerol) Aerodynamic diameter, Liposome vesicle size... 

Scheme 6.1 Structure of L-a-phosphatidylcholine (PC). R, and R2 are fatty acid residues.

This surprising property of alamethicin is not unique to the lipid DPhPC. Alamethicin behaves similarly in dioleoylphosphatidylcholine (DOPC) (Figure 7). Alamethicin in L-a-phosphatidylcholine from bovine brain (BBPC) at L P 50 1 also shows an I S transition as RH varies. Thus, these features appear to be the general characteristics of alamethicin in lipid membranes. In fact, our preliminary investigation indicates that amphipathic helical peptides may all have this property. Different combinations of peptide and lipid apparently have different values of critical L P. ... 

Figure 1.89 Structure of dipalmitoyl L-a-phosphatidylcholine (DPPC) to illustrate the main molecular parameters and structural features that dictate the formation of crystalline lamellar phases of macromolecular lipid assemblies. Schematic representation of a phospholipid molecule is also show (inset).

The antimicrobial activity of Origanum dictamnus L oil and their main components or mixtures increased when previously encapsulated in liposomes constituted by egg L-a-phosphatidylcholine and cholesterol prepared by thin-film method when compared to those not encapsulated (Liolios et al., 2009). 

Figure 1.20. Emission spectra of TNS in water, bound to apomyoglo-bin, and bound to lipid vesicles [dimyristoyl-L-a-phosphatidylcholine (DMPC)J. Reprinted, with permission from Wiley-VCH, STM, from Ref. 20.

Fig, 4, Temperature dependence of Mn transport rates. Vesicles were prepared by sonicating of L-a-phosphatidylcholine dipalmitoyl (Sigma) at 50°C. 71yM X-537A and ImM MnCl2 were added after son -cation. These measurements were performed with a 360 NH spectrometer in collaboration with A.C. McLaughlin (Brookhaven Lab.) and S.R. Simon (SONY at Stony Brook) ... 

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