Dipalmitoyl-phosphatidylcholine

McConnell et al. [196] and Andelman and co-workers have predicted [197,198] an ordered array of liquid domains in the gas-liquid coexistence regime caused by the dipole moment difference between the phases. These superstructures were observed in monolayers of dipalmitoyl phosphatidylcholine monolayers [170]. 

Gericke, a., Flach, C. R., and Mendelsohn, R. Structure and orientation of lung surfactant SP-C and L-alpha-dipalmitoyl-phosphatidylcholine in aqueous mono-layers. Biophys.J. 1997, 73, 492-499. 

T. E. (1978). Studies on anomalous thermotropic behavior of aqueous dispersions of dipalmitoyl phosphatidylcholine-cholesterol mixtures. Biochemistry. H, 1984-1989,... 

Since optical measurements of monolayers at the water-oil interface are rather difficult to carry out, a configuration was suggested where a monolayer at the water-air interface was in contact with an oil lens which was partly wetting the monolayer [23]. The thermodynamic relation between this monolayer and that residing at the water-oil interface was discussed. This configuration was utilized in the X-ray diffraction experiments [24] where the structural changes of dipalmitoyl phosphatidylcholine (DPPC) and DPPE were followed. 

DGDG digalactosyl diacylglycerol DHPC dihexadecyl phosphatidylcholine DMPC dimyristoyl phosphatidylcholine DOPC dioleoyl phosphatidylcholine DPPC dipalmitoyl phosphatidylcholine EYPC egg yolk phosphatidylcholine POPC 1-palmitoyl 2-oleoyl-phosphatidylcholine SBPC soya bean phosphatidylcholine... 

Cantrell et al. (2003) studied the quenching of 02 by several dietary carotenoids in dipalmitoyl phosphatidylcholine (DPPC) unilamellar liposomes. These workers used water soluble and lipid soluble 02 sensitizers so that a comparison of the efficiencies of quenching 02 generated within and outside the membrane model could be made. Perhaps surprisingly there was little difference in the efficiency of quenching in either situation. Typical results are presented in Table 14.3 (taken from Cantrell et al. (2003 and 2006)). 

F. Gerber, M.P. Krafft, T.F. Vandamme, M. Goldman, P. Fontaine, Fluidization of a dipalmitoyl phosphatidylcholine monolayer by fluorocarbon gases Potential use in lung surfactant therapy, Biophys. J. 90 (2006) 3184-3192. 

Fig. 2. Phase diagram describing lateral phase separations in the plane of bilayer membranes for binary mixtures of dielaidoylphosphatidylcholine (DEPC) and dipalmitoyl-phosphatidylcholine (DPPC). The two-phase region (F+S) represents an equilibrium between a homogeneous fluid solution F (La phase) and a solid solution phase S presumably having monoclinic symmetry (P(J. phase) in multilayers. This phase diagram is discussed in Refs. 19, 18, 4. The phase diagram was derived from studies of spin-label binding to the membranes.

Helm et al. [443] subsequently studied dipalmitoyl phosphatidylcholine (DPPC). They concluded that the condensed two-dimensional phase normally involves a tilt of the hydrocarbon chains of about 30°... 

Liposomes were first proposed for drug topical administration to the skin more than 25 years ago by Mezei and Gulusekharam [1,2]. The basic components of liposomes are phospholipids (phosphatidylcholine, phophatidylethanolamine, phophatidylserine, dipalmitoyl phosphatidylcholine, and others), cholesterol, and water. Liposomes may vary significantly in terms of size (from tens of nm to microns) and structure. In liposomes, one or more concentric bilayers surround an aqueous core generating small or large unilamellar vesicles (SUV, LUV) or multilamellar vesicles (MLV), respectively [3]. 

Muramatsu, K., et al. 1994. Effect of soybean-derived sterol and its glucoside mixtures on the stability of dipalmitoyl-phosphatidylcholine and dipalmitoylphosphatidylcholine/cholesterol liposomes. Int J Pharm 107 1. 

Figure 1 Experimentally determined values of ko obtained employing 3-methylindole as the quencher in homogeneous solvents, plotted as a function of the wavelength of maximum fluorescence intensity (data from Ref. 14). kap values determined in DODAC LUVs ( ) and in dipalmitoyl phosphatidylcholine (DPPC) LUVs (A) have been included. Also are included the experimentally determined value of kap in sodium dodecyl sulfate micelles ( ) and the value of kQ estimated from Eq. (21) ( ).

PHE, Phenol SA salicylic acid ASA O-acetylsalicylic add DPPC dipalmitoyl phosphatidylcholine. 

Guldbrand, L., Jonsson, B., and Wennerstrom, H. (1982) Hydration forces and phase equilibria in the dipalmitoyl phosphatidylcholine-water system. J. Colloid Interface Sci. 89(2) 532-541. 

The major (salvage) pathways for the formation of phosphatidylcholine and ethanolamine are illustrated in Figure 19.16. Free (dietary) choline and etha-nolamine are converted to their CDP derivatives, which then react with diacyl-glycerol to form phosphatidylcholine and ethanolamine. In the lungs, another pathway forms dipalmitoyl phosphatidylcholine, a powerful surfactant. Phos-phatidylethanolamine may be methylated by S-adenosylmethionine (SAM see Chapter 20) to yield phosphatidylcholine. The reaction is catalyzed by two enzymes the first methyl group is transferred via phosphatidylethanolamine N-methyltransferase I. The other two methyl groups are transferred by phosphatidylethanolamine N-methyltransferase II. Some authorities believe that the two enzymes are identical. It has also been proposed that methylation of phospha-... 

It should be pointed out that the NBF equivalent thickness hw is 7.6 nm while after Cei,cr, hw = 8.1 nm. The small difference in NBF thickness cannot be treated quantitatively but is an indications that there is no free aqueous core in the NBF. Assuming the three-layer film structure, refraction coefficient of tetradecane ri = 1.43, and, refraction coefficient of water, m = 1.33, on the basis of X-ray diffraction, neutron scattering and NMR data [289], we obtain hi = 1.6 nm. Hence, h2 = 3.8 nm and the total film thickness h2 + 2h equals 7.0 nm. This value is close to the results obtained by a completely different method for the thickness of two hydrated dipalmitoyl phosphatidylcholine monolayers - 6.8 nm, reported by Marra [290]. 

Vist, M. R. and Davis, J. H. (1990). Phase equilibria of cholesterol/dipalmitoyl-phosphatidylcholine mixtures H nuclear magnetic resonance and differential scanning calorimetry. Biochemistry 29 451. 

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