Chapter 2 Plasmalogens and O-alkyl glycerophospholipids

Glycerophospholipids with ether linkages are found in nearly all animal and bacterial cells with the exception of most aerobic bacteria. In contrast to the diacyl types of glycerophospholipids, the plasmalogens contain a hydrocarbon chain attached to glycerol through a dehydrated hemiacetal (vinyl ether) linkage and the alkylacyl glycerophospholipids contain a hydrocarbon chain attached through an ether linkage. The oxidation levels of the ether-linked side-chains are aldehyde and alcohol for plasmalogens and alkylacyl glycerophospholipids, respectively. Plasmalogens are glycerophospholipids containing a potential aldehyde that were first discovered in the plasma of cells. Thus the name was derived from plasm + al + ogen. A correct common name for 1-alk-1'-enyl-2-acyl-sn-glycero-3-phosphoethanolamine is "ethanolamine plasmalogen." Purified preparations of plasmalogens have been made by removal of the diacyl glycerophospholipids by mild alkaline hydrolysis, hydrolysis by phospholipase A2 from snake venoms and by hydrolysis by phospholipase D from cabbage. These methods depend on the lesser reactivity of plasmalogens.