Phosphatidic acid molecular species

El Bawab, S., Macovschi, O., Sette, C., Conti, M., Lagarde, M., Nemoz, G., and Prigent, A. F. (1997). Selective stimulation of a cAMP-specific phosphodiesterase (PDE4A5) isoform by phosphatidic acid molecular species endogenously formed in rat thymocytes. Eur J. Biochem. 247, 1151-1157. 

For examples of separation of lipids see general references. For tabulated examples, see Ref. B1 for separation of molecular species of phospholipids by HPLC, Ref. I for separation of lipids in food by HPLC, Ref. H for HPLC of phosphatidic acid, and Ref. B2 for preparative HPLC of lipids. 

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. 

The molecular arrangement of the bile acid-lipolytic product micelle is unknown but is probably similar to that of the bile acid-lecithin micelle, the structure of which, based on nuclear magnetic resonance studies, is a cylindrical bimolecular leaflet of lecithin molecules coated on the sides by bile acid molecules, their hydrophobic backs apposed to the paraffin chains of the phosphatide (65). All of the molecular species of the micelle are considered to be in rapid exchange with those of other micelles, as well as the concentration of molecularly dispersed lipolytic products and bile acids (at their CMC) in the bulk phase surrounding the micelles. Benzene molecules exchange rapidly between bile acid-monoglyceride micelles, a mean micellar... 

Comparison of in vivo and in vitro labelling of molecular species of phosphatidic acid and CDP-diglyceride... 

Justin AM, Mazliak P. Comparison of the molecular species patterns of phosphatidic acid, CDP-diacylglycerols and phosphatidylinositol in potato tuber, pea leaf and soyabean microsomes conseqences for the selectivity of the enzymes catalizing phosphatidylinositol biosynthesis. Biochim Biophys Acta 1992 1165 141-146. 

Abidi, S. L., T. L. Mounts, Separation of molecular species of phosphatidic acid by HPLC,/. Chromatogr, 1995,694, 365-373. 

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