Dipalmitoyl phosphatidylserine

MacDonald, R.C., Simon, S.P. Baer, E. (1976). Ionic influences on the phase transitions of dipalmitoyl phosphatidylserine. Biochemistry, 15, 885-97. 

The phase transition was induced by Ca and Mg in the case of dipalmitoyl-phosphatidylserine to form a condensed monolayer at the nitrobenzene-water interface, which was stable throughout the potential window. The capacitance in the presence of the condensed monolayer was as low as 1.5 pF cm [101]. The phase transitions from the expanded to the condensed monolayer accompanied the concomitant decrease in the rate of ion transfer but even the condensed monolayers were unable to block it completely [100, 101]. 

Materials. Egg phosphatidylcholine (PC), bovine brain phosphatidylserine (PS) were obtained from Avanti Polar Lipids Inc. (Birmingham, AL) and cholesterol was from Sigma (St. Louis, MO). Ganglioside GMj, bovine, was obtained from Calbiochem (San Diego, CA). Diethylenetriamine pentaacetic acid distearylamide complex (DPTA-SA) was synthesized according to ref. 17 and nlIn-DTPA-SA was prepared as described (7). This lipophilic radiolabel is not transferred to the serum components from liposomes (unpublished data), nor is it rapidly metabolized in vivo (7). The synthesis of N-(glutaryl)phosphatidylethanolamine(NGPE) has been described (18). Dipalmitoyl deoxyfluorouridine(dpFUdR) was synthesized as described (24). 

Fig. 21.2 Negative ion MALDI-TOF mass spectra of l-palmitoyl-2-oleoyl-sn-phosphatidyl-ethanolamine (a), l-palmitoyl-2-oleoyl-sn-phosphatidylserine (b) and 1,2-dipalmitoyl-sn-phosphatidylinositol-3-phosphate (c). In all cases a 0.5 M solution of DHB in methanol was used as matrix and the sample solutions (0.5 mg/ml) diluted 1 1 (v/v) with the matrix. All peaks are marked according to their m/z ratio and DHB matrix peaks are marked with asterisks. Please note the considerable intensity of the cluster ions between DHB and the different analytes. Please also note that the contribution of matrix peaks is much higher than in the positive ion spectra...

Abbreviations DMPC, DPPC, DSPC, dimyristoyl-, dipalmitoyl-,distearoyl-phosphatidylcholine DPPA, dipalmitoylphosphatidic acid PE, phosphatidylethanolamine PS, phosphatidylserine (U) and (M), unilamellar and multilamellar liposomes temperature of crystal liquid-crystal transition Diff. spectr., difference spectroscopy. 

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