Dipalmitoyl-phosphatidyl-cholin

Normal lungs, however, produce a chemical substance referred to as pulmonary surfactant. Made by alveolar type II cells within the alveoli, surfactant is a complex mixture of proteins (10 to 15%) and phospholipids (85 to 90%), including dipalmitoyl phosphatidyl choline, the predominant constituent. By interspersing throughout the fluid lining the alveoli, surfactant disrupts the cohesive forces between the water molecules. As a result, pulmonary surfactant has three major functions ... 

The nomenclature for associating individual fatty acid groups with particular phosphodig-lyceride derivatives is straightforward. For instance, a phosphatidic acid (PA) derivative which contains two myristic acid chains is commonly called dimyristoyl phosphatidic acid (DMPA). Likewise, a PC derivative containing two palmitate chains is called dipalmitoyl phosphatidyl choline (DPPC). Other phosphodiglyceride derivatives are similarly named. 

Results of Cserhati al. (1982) plotted as a function of the calculated log P of the surfactants used A) in determining the % reduction in growth of subtilis var niger and 0 . rhizobium and B) the change in efflux of from liposomes prepared from dipalmitoyl phosphatidyl choline. 

Figure 8.7. Fluorescence micrographs of a monolayer of L-a-dipalmitoyl phosphatidyl choline containing about 1% molar of an NBD dye at a temperature of 17°C and at pH 5.5. (Reproduced from Florsheimer, M. and Mdhwald, H. 1989 Chem. Phys. Lipids 49 231-41 by kind permission of the publishers and authors.)...

We have used osmotic stress (4) to examine the effect of Mg2 and Ca2 on the interactions between dioleoylphospha-tidylcholine or dipalmitoyl phosphatidyl choline bilayers. From the net repulsive forces between bilayers we are able to infer electrostatic potentials and charge densities at the site of ion binding these quantities are sensitive to bilayer separation. We find that at any particular bilayer separation dioleoyl phosphatidyl choline bilayers (melted hydrocarbon chains) adsorb less charge than dipalmitoyl phosphatidyl choline bilayers (frozen hydrocarbon chains) and that the binding of Ca2 is greater than that of Mg2 for both kinds of bilayers. 

We report here the results of a study of the adsorption of the alkaline earth cations to bilayer membranes formed from phosphatidylcholines with saturated chains dipalmitoyl phosphatidyl choline (DPPC) and dimyristoyl phosphatidyl choline (DMPC). Our salient result is that the adsorption of calcium is distinct from the other alkaline earth cations in two respects. First, only calcium adsorbs significantly more strongly to PCs with saturated chains than to phosphatidyl cholines with unsaturated chains, even when all lipids are present in the liquid crystalline state. Second, when the membranes are present in the frozen or gel state, the binding of calcium is significantly enhanced. We used two independent techniques to demonstrate this unique behavior of calcium. 

Dipalmitoyl phosphatidyl choline (L-a), alias DPL, and the sodium salt of dicetyl (hexadecyl or palmityl) phosphate were purchased from... 

In nature, polypeptides with amphiphilic structures are known to form transmembrane channels formed by an assembly of several helices, so as to present their polar faces inward and their apolar faces outward. In view of such behavior, the photochromic amphiphilic polypeptide was incorporated into a cationic bilayer membrane composed of dipalmitoyl phosphatidyl choline.11201 Fluorescence and microscopic measurements provided evidence that the polypeptide was able to form bundles of helical molecules analogous to their natural counterparts, which acted as transmembrane channels for K+ ions. Irradiation, and the consequent transacts isomerization of the azobenzene link, caused a bending of the molecular structure and a destabilization of the transmembrane bundles. Therefore, formation of ion permeable channels would be favored or inhibited depending on whether the azo moiety... 

The investigation was then extended to a monolayer formed from dipalmitoyl phosphatidyl choline and the same amphiphilic photochromic polypeptide XXIII.11211 When the monolayer was kept in the dark, the polypeptide molecules arranged themselves perpendicularly to the membrane (the water/air interface) and formed a bundle of helices which could be observed by atomic force microscopy as a transmembranous particle of about 4 nm in diameter. Irradiation with UV light and the consequent trans—>tis isomerization of the azobenzene moiety caused a bending of the molecular main chain, which in turn produced a destabilization and dena-turation of the bundle of helices in the monolayer. After removal of the light, the polypeptide molecules reverted to their original bundle structure. 1211... 

Dipalmitoyl phosphatidyl choline is one component of human lung surfactant, which coats the inner surfaces of the lung membranes and prevents them from clinging together and collapsing. Premature infants often produce little or no lung surfactant, which can lead to collapsed alveoli and other symptoms of infant respiratory distress syndrome (IRDS). 

Ma, L., Ramachandran, C., and Weiner, N. D. (1991), Partitioning of a homologous series of alkyl p-amino benzoates in dipalmitoyl phosphatidyl choline liposomes Effect of liposomes type, Int. J. Pharm., 70, 209-218. 

The structures of the two monomeric surfactants used in this work, 1,4 sorbitan sesquioleate (Arlacel 83) and L,o-dipalmitoyl phosphatidyl choline, used in the impure form of soya bean lecithin, are very different from the block copolymer Bl both can be considered to be V-shaped and about 3 nm in overall length. A comparison of the film thicknesses obtained for the three surfactants is given in Table V. The film thickness for sorbitan sesquioleate is... 

Before looking at the reconstituted membranes in more detail, we shall first discuss a simpler question concerning the distribution of ions in the aqueous phase of bilayer structures. Is the ion distribution in the water phase of typically 15 A width between the lipid surfaces homogenous, or is there a preferential binding to the polar head groups of the lipids These studies have been started in collaboration with G. Biildt and some preliminary results from dipalmitoyl phosphatidyl cholin (DPPC) membranes will be reported here. ... 

Respiratory distress syndrome is a pathological condition resulting from a failure in the biosynthetic pathway for dipalmitoyl phosphatidyl choline. This phospholipid, in conjunction with specific proteins and other phospholipids, is found in the extracellular fluid that surrounds the alveoli of the lung, where it decreases the surface tension of the fluid to prevent lung collapse at the end of the expiration phase of breathing. Premature infants may suffer from respiratory distress syndrome because their immature lungs do not synthesize enough dipalmitoyl phosphatidyl choline. 

A popular probe molecule which has b n employed for such studies is 1,6 diphenyl 1,3,5 hexatriene (DPH). This molecule has both absorption and emission along the long molecular axis and is thought to dissolve in the hydrocarbon interior. Time-resolved fluorescence depolarization studies with DPH probe molecules have been performed on the following bflayer syrtems dKdihydrosteraculoyl)pho halidyl choline dipalmitoyl phosphatidyl choline L-a-dimyristollecithin residues egg lecithin residues and mouse leukaemic L 1210cells In all reports the time-dependence of the emission anisotropy was found to decay non xponentially indkat-ing either... 

Figure 12. Epifluorescence (fluorescent probe, 23) photomicrograph of a mono-molecular film of the phospholipid dipalmitoyl phosphatidyl choline (10, R = R = n-CisHsi) at the air-water interface. The black regions are composed of solid-phase lipid, and the white (fluorescent) regions are fluid-phase lipid containing about 1 mol% of a fluorescent lipid probe. (Top) Micrograph showing the onset of solid phase formation bar, 50 pm. Middle) Micrograph showing formation of chiral solid domains when the phospholipid is one of the enantiomeric forms (R) bar, 50 pm. Bottom) Micrograph showing spiral forms of enantiomeric lipid when 2 mol% of cholesterol is included in the monolayer so as to reduce the line tension bar, 30 pm. Reproduced from ref. 146 (McConnell and Keller, Proc. Natl. Acad. Sci. USA 1987, 84,4706) with permission of the Academy of Sciences of the USA.

Dipalmitoyl- phosphatidyl-choline PPPC S f" —P-0-(CH2h-N CH3 0 6Hj 0 II C—CisHsi 0 II C—CisH3f... 

Recently, the competitive adsorption dynamics of phospholipid/protein mixed system at the chloroform/water interface was investigated by using the drop volume technique. The three proteins P-Lactoglobulin, P-Casein, and Human Serum Albumin were used in this study. To investigate the influence of the phospholipid structure at concentrations close to the CAC (critic aggregation concentration) the four lipids dipalmitoyl phosphatidyl choline (DPPC), dimyristoyl phosphatidyl choline (DMPC), dimyristoyl phosphatidyl ethanolamine (DMPE)... 

Thirumoorthy K, Nandi N, Vollhardt D, Oliveira ON (2006) Semiempirical quantum mechanical calculations of dipolar interaction between dipyridamole and dipalmitoyl phosphatidyl choline in Langmuir monolayers. Langmuir 22 5398... 

Abstract. Nonylphenyl-ethyleneoxide polymers containing 5, 9 and 30 ethyleneoxide groups per molecule build into the hydrophobic fatty acid chains of the cell membrane phospholipid dipalmitoyl-phosphatidyl-choline (DPPC) resulting in a decreased main transition temperature, a decreased enthalpy of the main transition and in enhanced potassium permeability of DPPC liposomes. The a-, jl- and y-cyclodextrins form inclusion complexes with the tenzides lowering their free concentration. The complex formation lessens or sometimes totally prevents the membrane damaging effect of tensides. The effectivity order of cyclodextrins is CD > yCD > aCD. 

In mammalian lipid interactions the structure and dynamics of sphingomyelin and dipalmitoyl-phosphatidyl-choline (DPPC) bilayers have been compared sterol-membrane interactions have been studied by comparative... 

De Miguel, I., A. Roueche, D. Betbeder, Separation of dipalmitoyl phosphatidyl choline, cholesterol and their degradation products by HPLC on a perfluorinated stationary bonded pha.se, J. Chromatogr. A, 1999, 840, 31-38. 

Abbreviations for amino acids and their derivatives follow the revised recommendation of the lUPAC-IUB Committee on Biochemical Nomenclature, entitled Nomenclature and Symbohsm for Amino Acids and Peptides (recommendations of 1983). Nomenclature of branched polypeptides is used in accordance with the recommended nomenclature of graft polymers (lUPAC-lUB recommendations, 1984). For the sake of brevity codes of branched polypeptides were constracted by us using the one-letter symbols of amino acids (Table 1). The abbreviations used in this paper are the following. AK, poly[Lys-(DL-Ala )] AXK, poly[Lys-(DL-Ala -Xi)] XAK, poly[Lys(Xi-DL-Ala )] X = Ser (SAK), Om (OAK), Glu (EAK), or Ac-Glu (Ac-EAK). All amino acids are of L-configuration unless otherwise stated. DPH, l,6-diphenyl-l,3,5-hexatriene ANS, sodium anilino naphthalene sulfonate DPPC, dipalmitoyl phosphatidyl choline PG, phosphatidyl glycerol Z, benzyloxycarbonyl Pep, pentachlorophenol P, polarisation. 

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