Plasmalogen structure

Plasmalogens protect biological structures against free radical attack (Maeba and Ueta, 2004 Engelmann, 2004) (Fig. 9.4). In neural membranes, transition metal... 

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)...

Guan Z., Wang Y., Cairns N. J., Lantos P L., Dallner G., and Sindelar P. J. (1999). Decrease and structural modifications of phosphatidylethanolamine plasmalogen in the brain with Alzheimer disease. J. Neuropathol. Exp. Neurol. 58 740-747. 

Draw the general structural formula of each of the following classes of compound (a) a (3-amino acid, (b) a nucleotide, (c) a plasmalogen, (d) an a-amino acid, (e) a tripeptide and (f) a diacylglycerol (diglyceride). 

It is important to stress that these tests represent presumptive evidence for a vinyl ether containing phosphoglyceride (plasmalogen), but not a final proof of structure. Other tests that can be used in conjunction with the above qualitative detection systems are the phosphorus spray and sulfuric acid char... 

The plasmalogens represent an unusual type of glycerophosphatide that has been isolated from animal and plant tissues. Acid hydrolysis of these materials yields long-chain aldehydes and mono-acylated a-glycerophosphate. The long-chain aldehydes originate from vinyl ether structures. The vinyl ether group appears usually (if not always) in... 

In plasmalogens or the subtle differences in their three-dimensional structure compared with that of other phosphoglycerides may have as-yet unrecognized physiologic significance. 

It was not until the 1950s that the precise chemical structure of the alk-l -enyl linkage in ethanolamine plasmalogens was proven, primarily through the combined efforts of... 

Fig. 33.4. General structure of a plasmalogen. Carbon 1 of glycerol is joined to a long-chain fatty alcohol by an ether linkage. The fatty alcohol group has a double bond between carbons 1 and 2. The head group is usually ethanolamine or choline.

Problem 19.33. Ionic head portions are not present in all membrane lipids. The other phospholipids, the plasmalogens and sphingomyelins, are like the phosphoglycerides in having an ionic head and two nonpolar tails, but the glycolipids and cholesterol do not possess ionic heads. What is the structural feature common to all membrane lipids ... 

Cell membranes have a fluid mosaic structure. The term fluid conveys the fluid (flexible) or liquid-like nature of the cell membrane. The term mosaic conveys the complex nature of cell membranes in terms of their structure and composition. Not only does the lipid bilayer contain different lipids (phosphoglycerides, plasmalogens, sphingomyelins, glycolipids, cholesterol), it also contains a variety of proteins essential to cell function. The physiological function of a membrane depends on its fluidity, which varies with the relative amounts of saturated fatty acids, unsaturated fatty acids, and cholesterol. 

Compare the structures and biosynthetic pathways of the glyceryl ether phospholipids, including platelet-activating factor and plasmalogens, with those of the glyceryl ester... 

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