The alkylacyl and alkenylacyl glycerophospholipids of human platelets.

The phospholipids of human platelets were isolated and analysed for their constituent 1-0-alkyl- and 1-0-(1'-alkenyl)glycerol species. The serine and inositol phospholipids contained only small amounts (0.5-1.6%) of both alkylacyl and alkenylacyl species; the ethanolamine phospholipids contained little alkylacyl (1.7%) but much more alkenylacyl (45.3%) species, while the choline phospholipids contained 4.5% and 1.4% of these compounds, respectively. Because choline phospholipids amount to 41% of the total phospholipids of human platelets, it appears that they could provide a sufficient supply of alkylacyl glycerophosphocholine for the generation of the alkylacetyl analog (platelet activating factor) by a deacylation-acetylation pathway.