Phosphatidic acid /phosphatidylcholine

Phosphatidic acid Phosphatidylcholine Phosphatidyl- ethanolamine Phosphatidylserine... 

Phosphatidic acids Phosphatidylcholines Phosphatidylserines Phosphatidylglycerols Phosphatidylethanol amines Phosphatidyl inositols Phosphatidylinositides Cardiolipins... 

Isolation of phosphatidyletha-nolamine, phosphatidic acid, phosphatidylcholine, and phospatidylinositol from soybean lecithin Isolation of phosphatidyletha-nolamine, phosphatidylcholine, phosphatidylinositol, and lysophophatidylcholine from soybean lecithin Separation of soybean leaf phosphatidylcholine according to acyl groups Fractionation of phosphatidylcholine according to degree of unsaturation... 

Fig. 1. Chemical stmcture of phosphatidylcholine (PC) (1) and other related phosphohpids. R C O represents fatty acid residues. The choline fragment may be replaced by other moieties such as ethanolamine (2) to give phosphatidylethanolamine (PE), inositol (3) to give phosphatidylinositol (PI), serine (4), or glycerol (5). IfH replaces choline, the compound is phosphatidic acid (6). The corresponding lUPAC-lUB names ate (1), l,2-diacyl-t -glyceto(3)phosphocholine (2), l,2-diacyl-t -glyceto(3)phosphoethanolamine (3), 1,2-diacyl-t -glyceto(3)phosphoinositol (4), 1,2-diacyl-t -glyceto(3)phospho-L-serine and (5), l,2-diacyl-t -glyceto(3)phospho(3)-t -glycetol.

In addition to the triglycerides, the four oilseeds also contain phosphatides. For example, soybean oil containing 1.47% phosphatides consists of 48.9% phosphatidylcholine, 27.0% phosphatidylethanolamine, 21.9% phosphatidjlinositol and 2.2% phosphatidic acid (24). Total phosphatides of cottonseed and peanut kernels are estimated to be 1.5—1.9 and 0.8%, respectively (25). 

Gainesis N., and Hauser, H. (1983). Characterization of small unilamellar vesicles produced in unsonicated phosphatidic acid and phosphatidylcholine-phosphatidic acid dispersions by pH adjustment, Biochim. Biophys. Acta, 731. 31-39. 

Figure 14-8. Phosphatidic acid and its derivatives. The 0 shown shaded in phosphatidic acid is substituted by the substituents shown to form in (A) 3-phosphatidylcholine, (B) 3-phosphatidylethanolamine,...

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). 

Fig. 23 Saliva and serum IgA (primary and secondary) response following orally administered soluble antigen Streptococcus mutans cell wall extract (open circles, soluble antigen solid circles, liposome-encapsulated material) (phosphatidylcholine, phosphatidic acid, cholesterol). (From Ref. 277).

PC = phosphatidylcholine, PE = phosphatidylethanolamine, PS = phosphatidylserine, PI = phosphati-dylinositol, Sph = sphingomyelin, FA = fatty acid, PA = phosphatidic acid, LPI = lyso-PI, CL = car-diolipin, LPC = Iyso-PC, CHO = cholesterol, CE = cholesterol ester, TG = triglycerides. 

Glycerol utilization depends on the tissue. Adipose tissue can t use glycerol. Nitrogen-containing phospholipids are made from diglycerides, while other phospholipids are made from phosphatidic acid (PA). PI = phosphatidylinosi-tol PC = phosphatidylcholine PE = phosphatidylethanolamine PS = phos-phatidylserine. 

The rate of production of DAG in the cell does not occur linearly with time, but rather it is biphasic. The first peak is rapid and transient and coincides with the formation of IP3 and the release of Ca2+ this DAG is therefore derived from the PI-PLC catalyzed hydrolysis of phosphatidylinositols [1]. There is then an extended period of enhanced DAG production that is now known to be derived from the more abundant phospholipid phosphatidylcholine (PC), which has a different composition of fatty acid side chains [9]. Although DAG may be generated directly from PC through the action of PC-PLC, it can also be formed indirectly from PC. In this pathway, PC is first hydrolyzed by PLD to give choline and phosphatidic acid, which is then converted to DAG by the action of a phos-phatidic acid phosphatase [10,11 ]. 

The activity of PLD on phosphatidylcholine generates phosphatidic acid, and this may be further metabolised by the enzyme phosphatidate phospho-hydrolase to form DAG (Fig. 6.19). Furthermore, the activity of DAG kinase can convert the DAG (generated either from phosphatidic acid or from the activity of PLC) back into phosphatidic acid. Both phosphatidic acid and DAG have functions as second messengers thus the activities of PLD, phosphatidate phosphohydrolase and DAG kinase all play important roles in the generation of these intracellular signalling molecules. 

Figure 6.19. Products of phosphatidylcholine metabolism. Phosphatidylcholine is metabolised to phosphatidic acid via the activity of phospholipase D. The phosphatidic acid generated in this way may then be converted into diacylglycerol via phosphatidate phospho-hydrolase (which is inhibited by propranolol), and the enzyme diacylglycerol kinase may regenerate the phosphatidic acid. Phospholipase D may also catalyse the transphosphati-dylation of primary alcohols, such as ethanol and butanol, at the expense of the natural substrate, phosphatidylcholine. Thus, primary alcohols can prevent phosphatidic acid production via this route.

Quinn, P.J., and Dawson, R.M.C., 1969, Interactions of cytochrome c and [ C] carboxylated cytochrome c with monolayers of phosphatidylcholine, phosphatidic acid and cardiohpin, Biochem. J. 115 65-75. 

Cholesterol 1.2-Diacylglycerol Phosphatidylcholine dilinoleoyl Sulfatlde Phosphatidyl-L-aerine LysO pho phatldylglycerol Phosphalidylglycerol Phosphatidic acid Cardiollpid (E coli) CardioUpid (bovine) Nona... 

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. 

Phosphatidic acid Phosphatidylethanolamine Phosphatidylcholine Occithin) Phosphatidylserine Phosphatidylinositol... 

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