Lipids choline

Rather similar data are shown in Table 2, which refers to displacement experiments carried out on microsomal Ptd-Cho pre-label-led Xn )Xi/lo from CDP-choline through the Kennedy pathway. Indeed, after 9 min of incubation, L-serine and ethanolamine displace the lipid-choline moiety by only 6% and 4%, respectively, and choline by only 2%. These data differ essentially from those described in Fig. 2, which reported the percentages of displacement rates of lipid-choline pre-labelled by base-exchange, and which... 

Pinally, the methylation pathway could represent an enzymic system linked to the source of choline in brain. It is known that the choline moiety as such cannot pass into the brain from the blood stream, but rather a lipid-choline moiety, probably lysophosphati-dylcholine, might be involved in the transport of the base. The methylation pathway, however, can be visualized as another means of producing choline in brain, provided Ptd-ethanolamine is transported into the brain. Conversely, due to the noticeable presence in the brain tissue of free serine, a possible pathway for choline production in brain may be represented by an exchange reaction between free serine and endogenous brain phospholipids, 9 20 cessive decarboxylation of phosphatidyl serine to Ptd-ethanolamine in the same tissue, finally followed by the described methylation reactions to produce a definite pool of active Ptd-choline,... 

The effect of prostaglandin F2a on arachidonate and lipid-choline metabolism in rat brain slices in vitro, in "Advances in Prostaglandin and Thromboxane Research", vol.3, G.GalU, C, Galli, and G.Porcellati, eds Raven Press, New York (1978). 

Phosphatidylcholine is an important component of cell membranes but cell mem branes are more than simply lipid bilayers Although their composition varies with their source a typical membrane contains about equal amounts of lipid and protein and the amount of cholesterol m the lipid fraction can approximate that of phosphatidylcholine The lipid fraction is responsible for the structure of the membrane Phosphatidyl choline provides the bilayer that is the barrier between what is inside the cell and what IS outside Cholesterol intermingles with the phosphatidylcholine to confer an extra measure of rigidity to the membrane... 

Plasmalogens are ether glycerophospholipids in which the alkyl moiety is d5-a,/3-unsaturated (Figure 8.10). Common plasmalogen head groups include choline, ethanolamine, and serine. These lipids are referred to as phosphati-dal choline, phosphatidal ethanolamine, and phosphatidal serine. 

Choline-containing lipids appear as orange-red spots in a few minutes... 

Ethanol and choline glycerolipids were isolated from calf brain and beef heart lipids by PTLC using silica gel H plates. Pure ethanol amine and choline plasmalogens were obtained with a yield of 80% [74]. Four phosphohpid components in the purple membrane (Bacteriorhodopsin) of Halobacterium halobium were isolated and identified by PTLC. Separated phosphohpids were add-hydrolyzed and further analyzed by GC. Silica gel G pates were used to fractionate alkylglycerol according to the number of carbon atoms in the aliphatic moiety [24]. Sterol esters, wax esters, free sterols, and polar lipids in dogskin hpids were separated by PTLC. The fatty acid composition of each group was determined by GC. 

Yoshiji, H., Nakae, D., Mizumoto, Y., Horiguchi, K., Tamura, K., Denda, A., Tsujii, T. and Konishi, Y. (1992). Inhibitory effect of dietary iron deficiency on inductions of putative preneoplastic lesions as well as 8-hydroxydeoxyguanosine in DNA and lipid peroxidation in the livers of rats caused by exposure to a choline-deficient L-amino acid defined diet. Carcinogenesis 13, 1227-1233. 

Hepatic steatosis usually is a result of excessive administration of carbohydrates and/or lipids, but deficiencies of carnitine, choline, and essential fatty acids also may contribute. Hepatic steatosis can be minimized or reversed by avoiding overfeeding, especially from dextrose and lipids.35,38 Carnitine is an important amine that transports long-chain triglycerides into the mitochondria for oxidation, but carnitine deficiency in adults is extremely rare and is mostly a problem in premature infants and patients receiving chronic dialysis. Choline is an essential amine required for synthesis of cell membrane components such as phospholipids. Although a true choline deficiency is rare, preliminary studies of choline supplementation to adult patients PN caused reversal of steatosis. 

Acetylcholine is formed from acetyl CoA (produced as a byproduct of the citric acid and glycolytic pathways) and choline (component of membrane lipids) by the enzyme choline acetyltransferase (ChAT). Following release it is degraded in the extracellular space by the enzyme acetylcholinesterase (AChE) to acetate and choline. The formation of acetylcholine is limited by the intracellular concentration of choline, which is determined by the (re)uptake of choline into the nerve ending (Taylor Brown, 1994). 

The other phospholipids that you may encounter are based on sphin-gosine. They are derived from serine instead of glycerol but the concept is the same. They have two long, fatty acid chains, a phosphate diester, and a choline-like charged group. This is a neutral lipid. 

Membrane/lipid metabolism/ choline/glycerophosphorylcholine/ Cho/ PCho GPCho/... 

Deroo, P.W., Rosenthal, A.F., Isaacson, Y.A., Vargas, L.A., and Bittman, R., Synthesis of DL-2,3-diacyloxypropylphosphonyl cholines from DL-2,3-diacy-loxyiodopropanes, Chem. Phys. Lipids, 16, 60, 1976. 

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