Phospholipids mixture from

Eibisch, M., Fuchs, B., Schiller, J., Su6, R., and Teuber, K. 2011. Analysis of phospholipid mixtures from biological tissues by matrix-assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI-TOF MS) A laboratory experiment. J. Chem. Educat., 88 503-507. 

Several cell lines were used to inveshgate the role of PS oxidahon in apoptosis. Preferenhal oxidahon of PS was observed in human leukemia HL-60 cells (Fabisiak et al, 1998, 2000 Kawai et al, 2000), and normal human keratinocytes (Shvedova et al, 2001). Similarly, in pheochromocytoma PC 12 cells exposed to a radical-generating anhneoplashc dmg, neocarzinostatin, extemalizahon of PS was potentiated by its selechve oxidation in whole cells (Schor et al, 1999). In contrast, this selechve PS oxidahon did not occur in liposomes prepared from mixtures of PnA-labeled phospholipids extracted from the ceUs and exposed to oxidants imder the same conditions (Fabisiak et al, 1998 Kagan et al, 2000 Shvedova et al,... 

Several investigators have used radioactive tracer methods to determine diffusion rates. Bangham et al. (32) and Papahadjopoulos and Watkins (33) studied transport rates of radioactive Na+, K+, and Cl" from small particles or vesicles of lamellar liquid crystal to an aqueous solution in which the particles were dispersed. Liquid crystalline phases of several different phospholipids and phospholipid mixtures were used. Because of uncertainties regarding particle geometry and size distribution, diffusion coefficients could not be calculated. Information was obtained, however, showing that the transport rates of K+ and Cl" in a given liquid crystal could differ by as much as a factor of 100. Moreover, relative transport rates of K+ and Cl" were quite different for different phospholipids. The authors considered that ions had to diffuse across platelike micelles to reach the aqueous phase. 

The observations on the aromas from cysteine + ribose reaction mixtures have been extended to compare the effect of different lipids triglycerides and phospholipids extracted from beef, and commercial egg lecithin (phosphatidylcholine) and egg cephalin (phosphatidylethanolamine) (L.J. Salter D.S Mottram, unpublished data). The inclusion of the beef triglycerides (TG) did not appear to have any effect on the aroma of the cysteine + ribose reaction mixture, which was sulfurous with an underlying meatiness. However, when beef phospholipids (FL) were used the meaty aroma increased markedly. Similarily, addition of egg lecithin (LEC) or egg cephalin (CEPH) to the cysteine + ribose reaction mixture gave increased meatiness, with the cephalin-containing mixture being judged to have the most meaty character. 

Tab. 4.20 Role of lipid head group in partitioning of teniposide into phospholipid mixtures. (Reprinted from Tab. 1 of ref. 79, with permission from Elsevier Science)...

FIG U RE 15.1 SFC-ELSD of phospholipid mixture with modified COj on the four stationary phases. The modifier consisted of methanol with 5 mM ammonium acetate. Chromatographic conditions flow rate of 2 mL/min, methanol/additive concentration raised from 15 to 55% at 4 min and held for 5 min at 55%. (From Yip, H.S.H. et al. Chromatographia 2007, 65, 655-665. With permission of Vieweg Verlag.)... 

Recovery of phospholipids, as well as the various neutral lipids, is obtained with good yields on aminopropyl tubes. Hence, Kaluzny s procedure was shown to recover up to 100% of all the lipid classes studied, giving better results than the TLC procedure [6]. This latter procedure has been extensively used by many workers to separate lipid mixtures from different origins. It has been slightly modified and adapted for particular use with poorer fractionation of lipid samples... 

Rohlfmg, A., Milthing, J., Pohlentz, G., Distler, U., Peter-Katahnic, J., Berkenkamp, S. and Dreisewerd, K., IR-MALDI-MS analysis of HPTLC-separated phospholipid mixtures directly from the TLC plate. Anal Chem, 79 (2007) 5793-5808. 

Figure 3. Transmission electron micrographs of gold plated vesicles formed from phospholipid mixtures a, 3 1 1 2, 80 kV b, 9 1 1 2. 200 kV c, andd, 3 1 1 3, 80 kV.

HPLC is now much used for the analysis of phospholipid mixtures after their extraction from biological sources (Figure 14.8). Phospholipid estimation has special uses in clinical diagnosis [42-45]. 

Figure 9.4 High-pressure liquid chromatography separation of 50 pg of a natural phosphatidylcholine mixture from egg yolk. The reconstructed ion chromatograms of diglyceride ions were selected from data acquired by full mass scanning from 120 amu to 820 amu. The relative intensity is shown based on the peak height. Column 3 pm Ultrasphere-ODS (4.6 mm x 7.5 cm). Mobile phase MeOH/hexane/0.1 m NH4OAC (71 5 7), 1 mlmin . Reprinted with permission from Kim, H. Y. and Salem, N. Jr, Phospholipid molecular species analysis by thermospray liquid chromatography/mass spectrometry. Anal. Chem., 58 (1), 9-14, 1986.

Schiff base compounds formed by the interaction of oxidation products with proteins, phospholipids and nucleic acids produce chromophores showing characteristic fluorescence spectra. The Schiff base formed between malonaldehyde and amino acids is attributed to the conjugated structure -NH=CH-CH=CH-NH-. Lipid-soluble fluorescence chromophores are produced from oxidized phospholipids and from oxidized fatty acid esters in the presence of phospholipids. These chromophores have fluorescence emission maxima at 435-440 nm and excitation maxima at 365 nm. The Schiff base of malonaldehyde and phospholipids has a higher wavelength maximum for emission (475 nm) and excitation (400 nm). The interaction between oxidized arachidonic acid and dipalmityl phosphatidylethanolamine produce similar fluorescence spectra (maximum excitation at 360-90 nm and maximum emission at 430-460 nm). The products from oxidized arachidonic acid and DNA have characteristic fluorescence spectra, with excitation maximum at 315 nm and emission maximum at 325 nm. Similar fluorescence spectra, with excitation maximum at 320 mn and emission maximum at420 nm, are obtained from the interactions of either lipid hydroperoxides or secondary oxidation products with DNA in the presence of metals and reducing agents, or different aldehydes, ketones and dimeric compounds from oxidized linolenate. Therefore, the Schiff base produced from various oxidized lipids and phospholipids and DNA may be considered to be due to a mixture of closely related chromophores. 

The phospholipid mixture isolated from brain was employed as a model system to study the free-radical oxidation chemistry using Cu(II) and H2O2 (Hall and Murphy 1998) to generate a hydroxyl radical by the Fenton reaction. The distribution of plasmenyl phosphohpids present in brain is somewhat different from that observed in erythrocyte membranes with the former having a high abundance of plasmenyl species with 18 1, 20 1, and 22 1 fatty acyl groups at the sn-2 position, which is comparable in abundance to those molecular species with 20 4, 22 4, and 22 6 fatty acyl groups at sn-2 (Khaselev and Murphy 1999). 

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