Ethanolamine and choline

Triacylglycerols and some phosphoglycerols are synthesized by progressive acylation of glycerol 3-phosphate. The pathway bifurcates at phosphatidate, forming inositol phospholipids and cardiolipin on the one hand and triacylglycerol and choline and ethanolamine phospholipids on the other. 

The ozonides of choline and ethanolamine phosphatides subjected to reduction with PhsP yield the corresponding core aldehydes. After hydrolysis with phospholipase C to eliminate the polar group and silylation with trimethylsilyl chloride, the core aldehydes can be determined by GLC-FID using temperature programming to high temperatures . ... 

The ozonides of choline and ethanolamine phosphatides and triglycerides can be subjected to reduction with triphenylphosphine to yield the corresponding core aldehydes, and further derivatized to the 2,4-dinitrophenylhydrazones (DNP). The core aldehydes and their DNP derivatives can be separated by HPLC and characterized by various techniques, including EI-MS and TS-MS of positive and negative ions . See also Section VHI.E. 

PC and PE are the most abundant phospholipids in most eukaryotic cells. The primary route of their synthesis uses choline and ethanolamine obtained either from the diet or from the turnover of the body s phospholipids. [Note In the liver, PC also can be synthesized from phosphatidylserine (PS) and PE (see below).]... 

Synthesis of PE and PC from preexisting choline and ethanolamine These synthetic pathways involve the phosphorylation of choline or ethanolamine by kinases, followed by conversion to the activated form, CDP-choline or CDP-ethanolamine. Finally, choline-phosphate or ethanolamine-phosphate is transferred from the nucleotide (leaving CMP) to a molecule of diacylglycerol (see Figure 17.5). 

Choline and ethanolamine are activated in much the same way as are sugars. For example, choline can be phosphorylated using ATP (Eq. 17-58, step a) and the phosphocholine formed can be further converted (Eq. 17-58, step b) to cytidine diphosphate choline. Phosphocholine is transferred from the latter onto a suitable acceptor to form the final product (Eq. 17-58, step c). Tire polymerization pattern differs from that for polysaccharide synthesis. When the sugar nucleotides react, the entire nucleoside diphosphate is eliminated (Eq. 17-56), but CDP-choline and CDP-ethanolamine react with elimination of CMP (Eq. 

The second phase of phospholipid synthesis in eukaryotes. Choline or ethanolamine enters the cell via active transport mechanisms and is immediately phosphorylated by the enzyme, choline (ethanolamine) kinase. The phosphorylated derivatives of choline and ethanolamine... 

It is postulated that inhibition of PtdCho synthesis and the release of choline are key steps associated with excitotoxicity and are common to NMDA and AMPA receptor stimulation. The mechanism of inhibition of PtdCho is not fully understood. Metabolic labeling experiments in cortical cultures demonstrate that NMDA receptor over activation does not modify the activity of phosphochohne or phospho-ethanolamine cytidylyltransferases but strongly inhibits choline and ethanolamine phosphotransferase activities. This effect is observed well before any significant membrane damage and cell death. Moreover, cholinephosphotransferase activity is lower in microsomes from NMDA-treated cells. These results show that membrane... 

Ronen, S.M., Rushkin, E Pegani, H. (1992). Lipid metabolism in large T47D human breast cancer spheroids 31P- and 13C-NMR studies of choline and ethanolamine uptake. Biochim. Biophys. Acta 1138,203-212. 

As mentioned in Chapter 2, the alkylacylcholine phosphoglycerides predominate in the choline-containing fraction in the majority of mammalian cells. On the other hand, the alkenylacyl form predominates in the ethanolamine-containing fraction. It is important to stress that these ether-linked lipids are found essentially only in the choline- and ethanolamine-containing phospho-glyceride. The reason for this high specificity of distribution is not known at present. 

Infante, J.P., Kinsella, J.E. 1976. Phospholipid synthesis in mammary tissue. Choline and ethanolamine kinases Kinetic evidence for two discrete active sites. Lipids 11, 727-735. 

Plasma levels of DHA, in cholesterol esters and phospholipids as well as erythrocyte phosphatidyl-choline and -ethanolamine, have been shown to be lower in patients with cystic fibrosis as compared with age-matched controls (Biggemann et al., 1988). Plasma phospholipid DHA has also been shown to be lower in well-nourished... 

Careaga-Houck M, Sprecher H. Effect of a fish oil diet on the composition of rat neutrophils lipids and the molecular species of choline and ethanolamine glycerophospholipids. J Lipid Res 1989 30 237-247. 

Yeo YK. Philbrick DJ, Holub BJ. Altered acyl chain compositions of alkylacyl, alkenylacyl, and diacyl subclasses of choline and ethanolamine glycerophospholipids in rat heart by dietary fish oil. Biochem Biophys Acta 1989 1001 25-30. 

Myocardial ischemia is accompanied by the release of arachidonic acid and the accumulation of lysophosphatidylcholine and lysophosphatidylethanolamine (cf, Corr et al., 1984). Arachidonic acid is predominantly stored in choline- and ethanolamine-glycerophospholipids in myocardium. Thus, these findings demonstrate that phospholipase A2 is activated during myocardial ischemia. Since lyso-phospholipids are potent amphiphilic compounds which have profound effects on the physical propwties of myocardial sarcolemma, the accumulation of these moieties has also been implicated in arrhythmogenesis. 

Ancelin, M. L. and Vial, H. J. (1986) Several lines of evidence demonstrating that Plasmodium falciparum, a parasitic organism, has distinct enzymes for the phosphorylation of choline and ethanolamine. FEBS Lett. 202 217-223. 

Simg, C.-P. Johnstone, R.M. Phosphorylation of choline and ethanolamine in Ehrlich ascites-carcinoma cells. Biochem. J., 105, 497-503 (1967)... 

Upreti, R.K. Sanwal, G.G. Krishnan, P. S. Likely individuality of the enzymes catalyzing the phosphorylation of choline and ethanolamine. Arch. Biochem. Biophys., 174, 658-665 (1976)... 

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