Phosphatidylcholine molecular species

RL Glass. Semipreparative high performance liquid chromatographic separation of phosphatidylcholine molecular species from soybean leaves. J Liq Chrom 14 339 -349, 1991. 

Demandre, C., Tremolieres, A., Justin, A hi., and Mazliak, P. (1986) Oleate Desaturation in Six Phosphatidylcholine Molecular Species from Potato Tuber Microsomes, Biochim. Bio-phys. Acta 877,38(U386. 

Demandre, C., Bahl, J., Serghini, H., Alpha, M.J., and Mazliak, P. (1994) Phosphatidylcholine Molecular Species Formed by Lysophosphatidylcholine Acyltransferase from Soya Bean Microsomes, Phytochemistry 35,1171-1175. 

Serghini-Caid, H., Demandre, C., Justin, A-M. and Mazliak, P. (1988) Oleoyl-phosphatidylcholine molecular species desaturated in pea leaf microsomes - possible substrates of oleate-desaturase in other green leaves. Plant Sci. 54, 93-101. 

I8j C. DEMANDRE, A. TREMOLIERES, A.M. JUSTIN and P. MAZLIAK - Oleate desaturation in six phosphatidylcholine molecular species from potato tuber microsomes. Biochim. Biophys. Acta, 71 380-386 (1986). 

These data Indicate that differences between phosphatidylcholine molecular species distributions In various plant tissues or organelles could result both from different dlacylglycerol pools existing In those tissues or organelles and also. In certain tissues, from the selectivity towards dlacylglycerols displayed by choline-phosphotransferase. 

ROLE OF PHOSPHATIDYLCHOLINE MOLECULAR SPECIES IN OLEATE DESATURATION... 

Fig. 5 Evolution of phosphatidylcholine molecular species percentages in apple embryos stored at 35°C.

Norman HA, Pillai P, St John JB. In vitro desaturation of monogalactosyldiacylglycerol and phosphatidylcholine molecular species by chloroplasts homogenates. Phytochemistry 1991 30 2217-22. 

Bernhard W, von der Hardt H. Bronchial surfactant phospholipid classes and phosphatidylcholine molecular species as indicators of its alveolar origin. Appl Cardio-pulm Pathol 1995 5(suppl 3) 6-7. 

A Cantafora, R Masella. Improved determination of individual molecular species of phosphatidylcholine in biological samples by high performance liquid chromatography with internal standards. J Chromatogr 593 139-146, 1992. 

P Therond, M Couturier, JF Demelier, F Lemonnier. Simultaneous determination of the main molecular species of soybean phosphatidylcholine or phosphatidylethanolamine and their corresponding hydroperoxides obtained by lipoxygenase treatment. Lipids 28 245-249, 1993. 

Lin, J. T., and McKeon, T. A. 2003. Relative retention times of the molecular species of acylglycerols, phosphatidylcholines and phosphatidylethanolamines containing ricinoleate in reversed-phase HPLC. /. Liquid Chromatogr. Rel. Technol., 26, 1051-1058. 

To assess the ability of the TC-CCC molecular species, two molecular species of phosphatidylcholine, which were synthesized, were subjected to TC-CCC. Dipalmi-toyl phosphatidylcholine (PC C16 0) and distearoyl phosphatidylcholine (PC C18 0), two of the major molecular species of phosphatidylcholine, were completely separated as shown in Fig. 4. Distearoyl phosphatidylcholine contains 2 mol of esterified stearic acids and dipal-mitoyl phosphatidylcholine contains 2 mol of esterified palmitic acid. The structures of these compounds are shown in Fig. 4. These two compounds were completely separated. This result indicates that the TC-CCC system can separate molecular species in both phospholipids and glycolipids categories. 

In this paper, we have shown that this system can separate molecular species. One example is shown for cerebrosides (Fig. 3B). Human phospholipids and glycolipids have many forms (molecular species) because of the variation in fatty acids or ceramides. Phosphatidylcholine, sphingomyelin, and cerebroside are each reported to consist of more than 100 molecular species.As shown in Fig. 4, it is possible to obtain better resolution by changing the flow rate and the volumes of the fractions. Furthermore, better conditions can be optimized by changing the composition of the solvents to target one hpid, as shown. 

From this comparison, it seems possible that the decrease of the 22 6n-3 species and the corresponding increase of the 22 5n-6 species seen in animals on the deficient diet may be the result of simple replacement of 22 6 with 22 5 through deacylation-reacylation. This is supported by the results of dual-labeling experiments in rat liver (Careaga-Houck and Sprecher, 1989). which suggested that de novo synthesis via phosphatidic acid is highly operative for the formation of monoenoic and dienoic molecular species of phosphatidylcholine, but that tetraenoic molecules are synthesized mainly by acylation of lysophosphatidylcholines. 

J. A. F. (1990) Plasmodium knowlesi induces alterations in phosphatidylcholine and phos-phatidylethanolamine molecular species composition of parasitized monkey erythrocytes. Biochim. Biophys. Acta 1022 135-145. 

In showing that the release of arachidonic acid was selective. Bills el al7 had studied the incorporation of several radiolabelled fatty acids into the complex lipids of human platelets and the subsequent fate of the radiolabel after stimulation of the platelets with thrombin. They found a dramatically greater loss from phosphatidylcholine of radioactive arachidonic acid compared with the other radiolabelled fatty acids. By contrast, Mahadevappa and Holub observed decreases in all the molecular species of phosphatidylcholine after thrombin treatment of platelets prelabelled with radioactive glycerol. They concluded that arachidonate is not selectively released from this phospholipid because the results obtained with radioactive fatty acids were due to unique patterns of incorporation, while those obtained with radioactive glycerol represented the endogenous phospholipid pool. 

Mahadevappa, V.G. and Holub, B.J. (1984). Relative degradation of different molecular species of phosphatidylcholine in thrombin-stimulated human platelets. ]. Biol Chem., 259, 9369-9373... 

Ahmad et al. (16) reported effects of n-3 EFAD on PL molecular species composition in the rat hippocampus. DHA was replaced by n-6 DPA in a highly reciprocal manner in phosphatidylethanolamine (PE). In phosphatidylcholine, the (palmitic acid)-DHA species was replaced by (palmitic acid)-DPA and (stearic acid)-DPA. In PE-plas-malogens, increases in both n-6 DPA and 22 4 n-6 compensated for the decrease in DHA. 

Ricinoleate (R) has many industrial uses. Its only commercial source is castor oil, in which ricinoleate constitutes 90% of the fatty acids (FA) (1). Castor beans contain toxic substances and are hazardous to grow, harvest, and process. Therefore, it is desirable to produce ricinoleate from a transgenic plant lacking these toxic substances. To develop a transgenic plant capable of producing a high level of ricinoleate in its seed oil, it is essential to understand the biosynthesis of castor oil. We previously established the biosynthetic pathway of castor oil and identified the key enzymatic steps of the pathway, which drive the ricinoleate into castor oil (2,3). We report here the identification and quantification of the molecular species of triacylglycerols (TAG, end products), phosphatidylcholines (PC, intermediate) and phosphatidylethanolamines (PE, intermediate) on the pathway incorporated from various [ C]-labeled FA and the comparison of the levels of their incorporation. 

Fig. 3. The C8 high-performance liquid chromatography (HPLC) radiochromatogram for the separation of molecular species of phosphatidylcholine (PC see Fig. 1,2 pL from 100 il methanol solution of PC and ricin-noleoyl-PC combined) from the castor microsomal incubation of [ " C]-oleic acid co-chromatographed with standard 1-palmitoyl-2-oleoyl-PC (For HPLC conditions, see Experimental Procedures.) (1) 1-ricinoleoyl-2-oleoyl-PC, 19.7 min (2) 1-linolenoyl-2-oleoyl-PC, 27.8 min (3) 1-linoleoyl-2-oleoyl-PC, 30.5 min (4) 1-palmitoyl-2-oleoyl-PC, 32.0 min (5) 1,2-dioleoyl-PC, 33.5 min (6) 1-stearoyl-2-oleoyl-PC, 36.3 min (7) 1-linolenoyl-2-ricinoleoyl-PC, 14.7 min (8) 1-linoleoyl-2-ricinoleoyl-PC, 16.9 min (9) 1-palmitoyl-2-ricinoleoyl-PC, 18.5 min (10) 1-stearoyl-2-ricinoleoyl-PC, 22.7 min (11) 1-linolenoyl-2-linoleoyl-PC, 25.0 min (12) 1-palmitoyl-2-linoleoyl-PC, 29.3 min.

Levels of the Incorporation of Various Radiolabeled Fatty Acids (FA) into Molecular Species of Phosphatidylcholines (PQ in Castor Microsomal Incubations (60 min)... 

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