Lipids phosphatidic acid

See also Molecular Structures and Properties of Lipids, Phosphatidic Acid, Cardiolipin, Phosphatidylserine, Phosphatidylethanolamine, Phosphatidylglycerol, Phosphatidylcholine, CDP-Diacylglycerol, Phosphatidylglycerol-3-Phosphate, Phosphatidylinositol, Lung Surfactant, Sphingolipids, Glycosphingolipids,... 

The nature of the separation achieved with a lipid extract from rat kidney is shown in Figure 2.5 [166]. In spite of the abrupt changes in solvent composition at various points, little base-line disturbance is apparent, and each of the main simple lipid and phospholipid classes is clearly resolved in only 20 minutes. Only the highly acidic lipids, phosphatidic acid and to a lesser extent phosphatidylserine, do not give satisfactory peaks. There is no "solvent peak" at the start of the analysis, as is often seen with other detectors, and BHT added as an antioxidant evaporates with the solvent so does not interfere. After a further 10 minutes of elution to regenerate the column, the next sample can be analysed. 

Kooijman EE, Carter KM, van Laar EG, Chupin V, Burger KN, de Kruijff B. What makes the bioactive lipids phosphatidic acid and lysophosphatidic acid so special Biochemistry. 2005 44(51) 17007-17015. 

Phosphatidic acids not only are intennediates in the biosynthesis of triacylglycerols but also are biosynthetic precursors of other members of a group of compounds called phosphoglycerides or glycerol phosphatides. Phosphorus-containing derivatives of lipids are known as phospholipids, and phosphoglycerides are one type of phospholipid. 

Lipid phosphate phosphohydrolases (LPPs), formerly called type 2 phosphatidate phosphohydrolases (PAP-2), catalyse the dephosphorylation of bioactive phospholipids (phosphatidic acid, ceramide-1-phosphate) and lysophospholipids (lysophosphatidic acid, sphingosine-1-phosphate). The substrate selectivity of individual LPPs is broad in contrast to the related sphingosine-1-phosphate phosphatase. LPPs are characterized by a lack of requirement for Mg2+ and insensitivity to N-ethylmaleimide. Three subtypes (LPP-1, LPP-2, LPP-3) have been identified in mammals. These enzymes have six putative transmembrane domains and three highly conserved domains that are characteristic of a phosphatase superfamily. Whether LPPs cleave extracellular mediators or rather have an influence on intracellular lipid phosphate concentrations is still a matter of debate. 

The SUM was covered by a polymer film with an orifice of approximately 0.3 mm in diameter on each side, and subsequently a folded BLM was generated from a DPhPC/l,2-dipalmitoyl-in-glycero-3-phosphatidic acid (DPPA) monolayer on the side facing the SUM (Fig. 19). Interestingly, no pretreating of the orifice with any alkane or lipid was required, as is imperative for all other BLM techniques. Thus, an accumulation of such compounds could be excluded, and the physicochemical properties of the membrane and... 

FIGURE 12.4 (A) Diagrammatic representation of the separation of major simple lipid classes on silica gel TLC — solvent system hexane diethylether formic acid (80 20 2) (CE = cholesteryl esters, WE = wax esters, HC = hydrocarbon, EEA = free fatty acids, TG = triacylglycerol, CHO = cholesterol, DG = diacylglycerol, PL = phospholipids and other complex lipids). (B) Diagrammatic representation of the separation of major phospholipids on silica gel TLC — solvent sytem chloroform methanol water (70 30 3) (PA = phosphatidic acid, PE = phosphatidylethanolamine, PS = phosphatidylserine, PC = phosphatidylcholine, SPM = sphingomyelin, LPC = Lysophosphatidylcholine). 

Six two-component models were tested under sink conditions (models 5.1-10.1 in Table 7.3), employing three negatively charged lipids (dodecylcarboxylic acid, phosphatidic acid, and phosphatidylglycerol). These models were also tested in the absence of the sink condition (models 5.0-10.0 in Table 7.3). 

The lipid component consists primarily of phospholipids and cholesterol. The most important group of phospholipids are phosphoglycerides, based on phosphatidic acid (where X = H), with the formula... 

The decreased level of free inositol leads to a reduction in the rate of Ptdlns resynthesis and to the subsequent accumulation of cytidine mo-nophosphorylphosphatidate (CMP-PA), the cosubstrate for the resynthesis, and of the other lipid metabolites, phosphatidic acid (PA) and DAG... 

Tang, J.-C., Tropp, B.E., Engel, R., and Rosenthal, A.F., Isosteres of natural phosphates. 4. The synthesis of phosphonic acid analogues of phosphatidic acid and acyldihydroxyacetone phosphate, Chem. Phys. Lipids, 17, 169, 1976. 

Elamrami, K. and Blume, A. (1983). Effect of lipid phase transition on the kinetics of H 1 /OH diffusion across phosphatidic acid bilayers, Biochim. Biophys. Acta, 727, 22-30. 

It can be seen from Figure 1 that the choline-containing phospholipids, phosphatidylcholine and sphingomyelin are localized predominantly in the outer monolayer of the plasma membrane. The aminophospholipids, conprising phosphatidylethanolamine and phosphatidylserine, by contrast, are enriched in the cytoplasmic leaflet of the membrane (Bretcher, 1972b Rothman and Lenard, 1977 Op den Kamp, 1979). The transmembrane distribution of the minor membrane lipid components has been determined by reaction with lipid-specific antibodies (Gascard et al, 1991) and lipid hydrolases (Biitikofer et al, 1990). Such studies have shown that phosphatidic acid, phosphatidylinositol and phosphatidylinositol-4,5-fc -phosphate all resemble phosphatidylethanolamine in that about 80% of the phospholipids are localized in the cytoplasmic leaflet of the membrane. 

Surger, K.N., Demel, R.A., Schmid, S.L. and de Kruijff, S., 2000, Dynamin is membrane-active lipid insertion is induced by phosphoinositides and phosphatidic acid. 

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