Glycerophosphocholine lipids

Several useful publications describing early direct injection API-electrospray methods appHcable to neurochemical studies include studies on acetylchoHnesterase phosphonylation products (Barak et al., 1997) glycerophosphocholine lipids (Flarrison and Murphy, 1996) receptor antibody characterization (Lewis et al., 1994) neuropeptide Yanalogs (Beck-Sickinger et al., 1994) and large biomolecules (Loo et al.,... 

SCHEME 21. Fragmentation pattern of the ozonide of an unsaturated glycerophosphocholine lipid in electrospray MS... 

Du L, White RL (2008) Reducing glycerophosphocholine lipid matrix interference effects in biological fluid assays by using high-turbulence liquid chromatography. Rapid Commun Mass Spectrom 22 3362-3370... 

LTC4 synthase. The mechanism by which 5-LO is trafficked to the nuclear membrane is controlled by the C2-like domain of 5-LO that binds two Ca " " ions which imparts high affinity for glycerophosphocholine lipids rich on the outer leaflet of either nuclear membrane [25]. 5-LO can be phosphorylated at S271 (MAPKAP kinase dependent) and S663 (ERK-1/2 dependent) to increase 5-LO activity and direct trafficking of 5-LO to the nucleoplasm. However, phosphorylation of S523, a protein kinase A-dependent process, inhibits 5-LO activity (see below). 

Hsu, F-F. Bohrer, A. Turk, J. Formation of lithiated adducts of glycerophosphocholine lipids facilitates their identification by electrospray ionization tandem mass spectrometry. J. Am. Soc. Mass Spectrom. 1997, 9, 516-526. 

K. A. Harrison and R. C. Murphy, Direct mass analysis of ozonides application to unsaturated glycerophosphocholine lipids. Anal. Chem. 68, 3224-3230 (1996). 

Kayganich-Harrison, K. A. and Murphy, R. C. (1994b) Characterization of chain-shortened oxidised glycerophosphocholine lipids using fast atom bombardment and tandem mass spectrometry. Analyt. Biochem., 221, 16-24. 

Harrison, K. A., R. C. Murphy, Negative electrospray ionization of glycerophosphocholine lipids formation of M-15 ions occurs via collisional decomposition of adduct anions, 7. Mass Spectrom., 1995,70, 1772-1773. 

The location of the double bonds in unsaturated glycerophosphocholine (GPC) lipids is made difficult mainly due to the limited amounts of these compounds isolated from cells. When a thin layer of a GPC lipid is exposed to the action of ozone, partial or total ozonization of the unsaturated fatty acid residues may take place, depending on the particular compound being analyzed. The ozonized hpid is dissolved and analyzed by tandem MS. A typical injection into the instrument may be 5 xL containing 10-20 ng of the lipid. An illustrative example is the ozonized l-stearoyl-2-arachidonoyl-GPC, showing the systematic fragmentation pattern in Scheme 21, typical of the ozonized GPC lipids. Thus, the molecular peak appears increased by one nominal unit (M + H, m/e 1002),... 

Polette, A., Deshayes, C., Chantegrel, B., Croset, M., Armstrong, J.M. and Lagarde. M. (1999) Synthesis of acetyl,docosahexaenoyl-glycerophosphocholine and its characterization using nuclear magnetic resonance. Lipids. 34 1333-1337. 

P. Glynn and co-workers showed that NTE is anchored to the cytoplasmic face of the endoplasmic reticulum (ER) via its transmembrane helix (TM), its R-and C-domains also interact with the cytoplasmic face of the ER [39], It has been found that NTE possesses phospholipase [44] and lisophospholipase activity [46] in addition to its ability to hydrolyze carboxy ester substrates [3,12,41], The last published work from this lab demonstrated that NTE and its homologues deacylate phosphatidylcholine, the major membrane lipid in eukaryotic cells, to glycerophosphocholine and by this means play a central role in membrane lipid homeostasis [47],... 

These effects are not specific for dipalmitoyl glycerophosphocholine thus, unsaturated phosphatidylcholines and the lipid extract of human erythrocyte ghosts exhibit similar behaviour. The explanation for this behaviour is that addition of cholesterol to the lipid-water system causes a reduction in the cohesive forces between adjacent ordered hydrocarbon chains of the hpid preventing chain crystallisation leading to an increase in fluidity of the lipid chains. The presence of water is also of prime importance in this interaction and cholesterol is precipitated when most of the water is removed. 

A new class of sterol-modified lipids (38-40), obtained by linking sterols to both hydroxyl groups of glycerophosphocholine in a one-pot synthesis, has... 

Fig. 7.12 Lipid profiling in bovine lens tissue by MALDI-MS. Glycerophosphocholines (PC) and phosphonosphingolipids (SM) profile of the outermost cortex region, fixed in 2.5% formaldehyde buffered at pH 7.4. (Reprinted with permission from [222] copyright 2004, American Chemical Society)...

Kanda, P. and Wells, M.A. (1981) Facile acylation of glycerophosphocholine catalyzed by trifluoroacetic anhydrid. J Lipid Res. 22, 877-879. 

Khaselev, N. and Murphy, R.C. (2000) Structural characterization of oxidized phospholipid products derived from arachidonate-containing plasmenyl glycerophosphocholine. J. Lipid Res. 41, 564-572. 

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