Choline plasmalogen

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. 

Fig. 9.4 Chemical structures of cellular lipids that act as endogenous antioxidants. Choline plasmalogens (a) ethanolamine plasmalogens (b) ganglioside (c) and vitamin E (a-tocopherol) (d)...

The fatty acid composition of muscle lipids may show quantitative alterations in diseased muscle. Thus lecithin isolated from human dystrophic muscle had an increased amount of oleic but diminished linoleic acid (Tl). Changes have been recorded also in the fatty acid composition of lecithin from denervated muscle (PI). Recently it has been reported (K16) that the fatty acid pattern of muscle phosphatides from patients with the autosomal dominant form of myotonia congenita differed markedly from that of the autosomal recessive form and from the normal. Tani and his co-workers (F7) have made a detailed study of the phospholipids of normal and dystrophic mouse tissues. In normal mice phosphatidylcholine and phosphatidylethanolamine from skeletal and heart muscles had a very high content of 20-22-carbon polyunsaturated acids, in comparison with those for other tissues the most abundant was docosahexaenoic acid. In dystrophic mice there was a sharp decrease in the proportion of docosahexaenoic acid in the phosphoglycerides from skeletal and heart muscles, suggesting the likelihood of important alterations in muscle membranes. Somewhat similar studies have been reported by Owens (05), who also observed a fall in the proportion of docosahexaenoic acid, mainly in the phosphatidylcholine -j- choline plasmalogen fraction. 

Euchs, B., Muller, K., Goritz, E., Blottner, S. and Schiller, J., Characteristic oxidation products of choline plasmalogens are detectable in cattle and roe deer spermatozoa by MALDI-TOE mass spectrometry. Lipids, 42 (2007b) 991-998. 

Fig. 7. Biosynthesis of choline plasmalogens (plasmenylcholines) via modification of the sn-3 polar head group of ethanolamine plasmalogens (plasmenylethanolamines). These reactions are proposed to be catalyzed directly by (1) a base exchange enzyme or (II) At-methyltransferase. A combination of other enzymatic reactions could also result in replacement of the ethanolamine moiety of plasmenylethanolamine to produce plasmenylcholines the enzymes responsible include (IB) phospholipase C, (IV) the reverse reaction of ethanolamine phosphotransferase, (V) phospholipase D, (VI) phosphohydtolase, and (VII) cholinephosphotransferase. AdoMet, 5-adenosyl-L-methionine AdoHcy, 5-adenosyl-L-homocysteine Etn, ethanolamine GPE, sn-glycero-...

A substance with similar pharmacological activity could be obtained from a choline plasmalogen prepared from heart. The choline plasmalogen is now known to be glycerol l-alkenyl-2-acyl-3-phosphorylcholine (II) [see Gottfried and Rapport (1962), for references]. 

Horrocks, LA, Yeo, YK, Harder, HW, Mozzi, R and GoraccL G (1986) Choline plasmalogens, glycerophospholipid methylation, and receptor-mediated activation of adenylate cyclase. In Advances in Cyclic Nucleotide and Protein Phosphorylation Research, Vol. 20 (P Greengard and GA Robison, eds.). Raven Press, New York, pp.263—292. 

The aldehydes, which have been isolated from these plasmalogens, are predominantly saturated and monounsaturated aldehydes (16 0, 18 0, 18 1, 18 1 ). In contrast, the fatty acids linked to the /9-C-atom in choline plasmalogens are mostly Cig-unsaturated fatty acids, no C22-polyenoic acids have been observed (Klenk et al. 1957 Debuch 1956). Heart muscle mainly contains choline plasmalogens, whereas brain tissue has ethanolamine and serine plasmalogens (Klenk et al. 1951 Ansell et al. 1956). These are localized in brain white matter (Webster 1960). Previous attempts to separate diacylglycerophosphoryl choline or -ethanolamine from the respective plasmalogens were unsuccessful. 

PiETRUSZKO, R., and G. M. Gray Formation of the cyclic acetal phospholipid during alkaline and enzym hydrolysis of choline plasmalogen. Biochem. biophys. Acta (Amst.) 44,197 (1960). 

It is now generally agreed that choline plasmalogen (VII) may be represented by the unsaturated ether structure of Rapport and co-workers (Rapport et al. 1957, Rapport and Franzl 1957a), who suggest that the compound be referred to as phosphatidal choline. 

Information concerning the biosynthesis of choline plasmalogen is somewhat limited. Most of the work on the biological formation of plasmalogens has been done on ethanolamine plasmalogen (see below) rather than choline plasmalogen. An exception is the report of Keenan, Brown and Marks (1961), who showed that C -labelled fatty acids are incorporated in both the acyl ester group and the... 

An important step was the finding of Kiyasu and Kennedy (1960) that rat liver contains an enzyme that is able to catalyse the formation of choline plasmalogen from CDP-choline and plasmalogenic diglyceride ... 

The principal plasmalogen of brain contains ethanolamine rather than choline. The work of Rapport and associates (Rapport et al. 1957, Rapport and Franzl 1957 b) indicates that the structure of this compound is analogous to that previously described for choline plasmalogen, i.e. phosphatidal ethanolamine (X). 

This reaction is analogous to that previously described for the biosynthesis of choline plasmalogen (Reaction 17). It also occurs in brain tissue (McMurray 1964b). 

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