Lyso-phosphatidylcholine

Glycerophospholipids contain a glycerol skeleton to which two fatty acids are esterified saturated fatty acids occupy mostly sn-position 1, whereas unsaturated fatty acids are mainly present on sn-position 2. The third hydroxyl is linked to a phosphate group to which an organic base is mostly esterified (Fig. 1). The most important components of soybean lecithin are phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylinositol (PI). Phosphatidic acid (PA) may become important due to the presence of phospholipase D this enzyme slowly converts PC into PA in vegetable lecithins. Phosphatidylserine (PS), phosphatidylglycerol (PG), and lyso-phosphatidylcholine (LPC) are known as minor components lysophospholipids contain only one acyl group per molecule. Besides, ether phospholipids occur in which one or both fatty acyl... 

Koizumi S, Yamamoto S, Hayasaka T, Konishi Y, Yamaguchi-Okada M, Goto-Inoue N, Sugiura Y, Setou M, Namba H (2010) Imaging mass spectrometry revealed the production of lyso-phosphatidylcholine in the injured ischemic rat brain. Neuroscience 168 219-225. doi 10.1016/j.neuroscience.2010.03.056... 

Abbreviations APCI Atmospheric Pressure Chemical Ionization DAG Diacyl-glycerols DE Delayed Extraction DHB 2,5-Dihydroxybenzoic Acid El Electron Impact ESI Electrospray Ionisation FACS Fluorescence-activated cell sorting GC Gas Chromatography HDL High Density Lipoprotein HPLC High-Performance Liquid Chromatography IR Infrared LDL Low Density Lipoprotein LOD Level of Detection LOQ Level of Quantification LPC Lyso-Phosphatidylcholine LPL Lyso-Phospholipid MALDI Matrix-... 

The most abundant membranes in nature are the thylakoids inside chloroplasts of green plants. A surprising amount of lipid traffic is involved in the assembly of these membranes. Almost all the acyl chains that form the core of the photosynthetic membranes are first produced by fatty acid synthase in the chloroplast. In most plants these acyl chains are then exported to the ER where they become esterified to glycerol, desaturated while they are part of phosphatidylcholine and then are returned to the plastid. The exact mechanisms for the export and return of acyl chains are still uncertain although much has been learned (Chapter 17) [10]. The export from plastids across the chloroplast envelope membranes is known to involve a fatty acid intermediate, and probably is a channeled or facilitated process rather than free diffusion because only a tiny pool of free fatty acid is ever detected (A. Koo, 2004). An acyl-CoA synthetase on the envelope membrane is believed to quickly convert the exported fatty acid to a thioester form that is then a substrate for acyltransferases. Transfer of acyl groups to the ER may occur via diffusion of the acyl-CoAs however, recent evidence suggests this initial acyl transfer reaction involves acylation of lyso-phosphatidylcholine and may occur at the chloroplast envelope. 

Fig. 10. Fatty acids at both sn- and sn-2 positions of PC can be deacylated by phospholipases and used for reacylation by acyltransferases. For example, palmitic acid (16 0) can be removed from the sn-l position and replaced with stearic acid (18 0). The fatty acid at the sn-2 position is depicted as docosahexaenoic acid (22 6) that can be replaced with 20 4 or 18 2. If the fatty acid at the sn-2 position were oleic acid, it could also be deacylated and reacylated. Alternatively, deacylation/reacylation could occur initially at the sn-2 position. Plipase, phospholipase 1-AT, acyl-CoA lyso-phosphatidylcholine 1-acyltransferase 2-AT, acyl-CoA lyso-phosphatidylcholine 2-acyltransferase cho, choline.

Fig. 2.4 Diagram showing the effect of ischemic injury on glycerophospholipid-derived iipid mediators in brain. Plasma membrane (PM) iV-methyl-D-aspartate receptor (NMDA-R) giuteimate (GIu) phosphatidylcholine (PtdCho) lyso-phosphatidylcholine (lyso-PtdCho) cytosolic phospholipase A2 (CPLA2) secretory phospholipase A2 (SPLA2) cyclooxygenase (COX-2) arachidonic add (ARA) platelet-activating factor (RAF) 4-hydroxynonenal (4-HNE) reactive oxygen species (ROS) nuclear factor kappaB (NF-kB) nuclear factor kappaB response element (NF-kB-RE) inhibitory subunit of NFkB (IkB) tumor necrosis factor-a (TNF-a) interleukin-ip (IL-ip) interleukin-6 (IL-6) matrix metaUoproteinases (MMPs) positive sign (+) represents upregulation...

Adibhatla RM, Hatcher JF, Dempsey RJ (2004) Cytidine-5 -diphosphocholine affects CTP-phosphocholine cytidylyltransferase and lyso-phosphatidylcholine after transient brain ischemia. J Neurosci Res 76 390-396... 

Figure 4.21 NMR spectrum of soybean lecithin. LPA = lyso-phosphatidic acid PA = phosphatidic acid PG = phosphatidylglycerol LPE = lyso-phosphatidylethanolamine DPG = diphosphatidylglycerol (or sphingomyelin SPH) APE = A-acyl-phosphatidylethanolamine PE = phosphatidylethanol-amine PS = phosphatidylserine LPC = lyso-phosphatidylcholine PI = phosphatidylinositol PC = phosphatidylcholine. Instrument details are given in text,...

Figure 4.22 NMR spectrum of a liposome formulation containing phosphatidylcholine (PC) and degradation products 1-Iyso-phosphatidylcholine (I-LPC), 2-lyso-phosphatidylcholine (2-LPC) and glycerophosphatidylcholine (GPC). Instrument details are given in text. Section 4.10.

Hg.3. Effect of methanol concentration on acyltransferase activity of lipolytic acyl hydrolase. Amounts of free fatty acids (circles) and fatty acid methyl esters formed (triangles) or lyso-phosphatidylcholine deacylated (squares) in 10-min incubations at 2S°C are given as percentage of substrate (lysophosphatidylcholine) added. (Reproduced from Galliard and Dennis, 1974, by permission.)... 

Addition of radiolabeled [l,2- C]choline to plant tissue rather specifically labels PC. Marshall and Kates (1974) found 10% of the labeled lipid as lyso-phosphatidylcholine. (LPC). Tang and Castelfranco (1968) have published chromatograms of lipids from potato (Solanum tuberosum L.) tuber slices labeled by choline. In addition to PC there were minor spots which could correspond to LPC. Moore (1977) used [l,2- C]choline to label PC in soybean suspension cultures. The only lipid labeled was PC, and its degradation was followed after a 2-h pulse of radioactivity. The cells grew exponentially and then entered stationary phase turnover half-times in these two phases were 36 and 96 h. 

FIGURE 49.7 (A) Structural elucidation of lipids by MALDI-TOF/TOF analysis (B) analysis of the MS/MS spectrum of lyso-phosphatidylcholin several fragments were assigned to lipid moeities (marked in the lipid structure representation). Intens. [a.u.], intensity (in arbitrary units) PG, phosphatidyl glycerol PE, phosphatidyl ethanolamin PA, phosphatidic acid PC, phosphatidyl cholin SM, sphingomyelin LPC, lyso-phosphatidyl cholin. 

Fig. 10.11. Postmortem degradation of phosphatidylcholines and increase in lyso-phosphatidylcholines. An IMS series was performed on mouse brains extracted after different amounts of time had elapsed after sacrifice (within 1,15,30,60, and 120 min after sacrifice). After IMS, the ion intensities of the PCs were averaged over the entire section. As postmortem events, degradation of PCs and an increase in lyso-PCs were observed within 15 min, presumably because of the stimulation of phospholipase A under ischemic conditions (37, 38). In this study, mouse brains were extracted within 1 min (typically within 40 s) after sacrifice. Reprinted from Ref. (11).

Gomes, E., Venema, K., Simon-Plas, R, Milat, M.-L., Gjedde Pahngren, M. Blein, J.-P. (1996). Activation of the plant plasma membrane H -ATPase. Is there a direct interaction between lyso-phosphatidylcholine and the C-terminal part of the enzyme FEBS Letters, 398, 48-52. 

Choline-containing phospholipids (phosphatidylcholine and lyso-phosphatidylcholine)... 

The pancreatic enzyme mainly responsible for retinyl ester hydrolysis appears to be the same enzyme that catalyzes intraluminal cholesteryl ester hydrolysis (Erlanson and Boigstibm, 1968 Lombardo and Guy, 1980). This enzyme has been purified from rat (Calame et al.. 1975) and from porcine (Momsen and Brockman, 1977) pancreas, and from human pancreatic juice (Lombardo et al.. 1979). The enzyme appears to be a relatively nonspecific carboxylic ester hydrolase that can act on a wide variety of esters as substrates. Thus the purified human enzyme hydrolyzes triacetin, tributyrin, p-nitrophenylacetate, and lyso-phosphatidylcholine, as well as esters of cholesterol and of vitamins A, Dj, and E and glycerides solubilized by bile salts. Its molecular weight (approximately 100,000) is greater than that of the rat or pig enzyme, and it can hydrolyze... 

Figure 2.4. Isocratic elution of rat liver phospholipids from a column of silica gel with hexane-isopropanol-25 mM phosphate buffer-ethanol-acetic acid (367 490 62 100 0.6 by volume) as mobile phase at a flow-rate of 0.5 mL/min for the first 60 minutes then of 1 mL/min, and with spectrophotometric detection at 205 nm [694]. (Reproduced by kind permission of the authors and of the Journal of Lipid Research, and redrawn from the original publication). Abbreviations NL, neutral lipids PE, phosphatidylethanolamine PA, phosphatidic acid PI, phosphatidylinositol PS, phosphatidylserine DPG, diphosphatidylglycerol PC, phosphatidylcholine SPH, sphingomyelin LPC, lyso- phosphatidylcholine XI, X2, X3 and X4, unidentified lipids.

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