Dipalmitoyl-a-L-lecithin

R-l,2-Dipalmitoyl-sn-glycero-3-phosphocholine monohydrate (dipalmitoyl-a-L-lecithin)... 

J -l,2-Dipalmitoyl- n-glycero-3-pho phocholine monohydrate (dipalmitoyl-a-L-lecithin) [63-89-8] M 752.1, m sinters at 120°, [a] +7.0° (c 5.6, absointe CHCI3), pKji,t 5.8 (PO4). It has three ciystalUne forms ai, and P which change at 60-70° and at 229°, respectively. In order to obtain a fine powder, 2 g are dissolved in CHCI3 (15ml) and petroleum ether (b 35-60°) is added the solution is evaporated to dryness in vacuo at <20° and then dried at 0.1mm over CaCl2. [Baer Maurukas JAm Chem Soc 74 158 1952, Baer Kates JB/o7 Chem 185 615 1950, Beilstein 4 IV 1463.]... 

Materials. The water used for all purposes was double-distilled (once with glassware) and deionized (final conductance was less than 1 X 10"6 ohm1 cm."1). Stearic acid (obtained from Sigma Chemical Co.) was at least 99% pure as determined by silica gel thin-layer chromatography (4), and the synthetic L-a(/ ,y-dipalmitoyl) lecithin was about 90% pure (see Ref. 13 for analysis). The ATP-14C and its derivatives were obtained from Nuclear-Chicago or New England Nuclear Corp. and were found to be 95-98% pure as determined by cellulose thin-layer chromatography (16). 

Penetration of electrolytes into both the air-water interface and films of dipalmitoyl lecithin is accompanied by a relatively small surface potential increase, whereas hydrolysis of CaCl% produces accumulation of Ca(OH)t and related species at the interface (l). Although in the absence of ionic lipids a correlation between interfacial ionic populations of the electrolyte and the surface potential changes is not yet possible, the marked surface potential effects of CaCU accompanying the presence of small quantities of acidic phospholipids in dipalmitoyl lecithin films suggest that the acidic lipid contaminants are still the only certifiable species whose interaction with CaCl2 produces an appreciable surface potential increase. Surface radioactivity and IR absorption spectra of dipalmitoyl lecithin in the presence of CaCU produced no evidence of Ca -dipalmitoyl lecithin interaction. 

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... 

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... 

Baer (1953) has recorded the spectra of pure dimyristoyl, dipalmitoyl, and distearoyl L-a-lecithins. Baer et al. (1952) have also recorded spectra of L- -cephalins, namely, the same kinds of fatty acid derivatives. The spectra have differences, although this is not true for the corresponding straight-chain fatty acids. In the region from 870 to 714 cm" several large differences occur. 

Synonyms L-a-1,2-Dipalmitoyl phosphatidylcholine DPPC Uses Emulsifier, solubilizer for dermatology and cosmetics for mfg. of liposomes and mixed micelles Manuf./Distrib. Genzyme http //www.genzyme. com Trade Name Synonyms Phospholipon PC t[Am. Lecithin... 

L-a Glycerophosphorylcholine cadmium chloride complex was prepared by hydrolyzing egg lecithin which was isolated from egg yolk. 1-Dodecyne, undecylenic acid, 11-bromo undecanoic acid, nonanoic acid, lithium acety-lide ethylenediamine complex, dimethylaminopyridine (DMAP), and dicyclo-hexylcarbodiimide (DCC) were purchased from Aldrich Chemical Co. Milwaukee, WI. Tridecyne was obtained from Farchan Laboratories, Gainesville, FL, and 1,2-dihexanoyl and 1,2-dipalmitoyl PC were purchased from Avanti Polar Lipids, Birmingham, AL. Mixed bed resin AG 501-X8(D) was procured from Bio-Rad Laboratories, Richmond, CA. Chloroform was distilled freshly over phosphorus pentoxide just before the use. Other solvents were used as received. The water was triply distilled and deionized. 

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