Platelets and Platelet Phosphatides

The advent of teehniques for separating lipids into individual classes 

In contrast, results with the ethanolamine phosphoglycerides have 

The fatty acid composition of the serine phosphoglycerides was relatively simple (Marcus et al., 1962). The main saturated fatty acid was stearic, which was present in amounts equal to the sum of the unsaturated fatty acids, oleic and arachidonic. There was very little plasmalogen in the serine phosphoglycerides, as was also noted by Speer and Ridgway (1962). The fatty acid and aldehyde composition of inositol phosphatide (PI) was quite similar to that of PS. There were trace amounts of serine phosphoglycerides in the PI fractions, but it was felt that they did not contribute to the overall pattern. In contrast to the cephalin fractions, the lecithins contained large quantities of palmitic and oleic acids. As with platelet PS, the plasmalogen component in the lecithin fractions was small. 

It had been previously shown by Rouser and Schloredt (1958) that the degree of imsaturation of fatty acids in phosphatides might be directly correlated with clot-promoting activity. Thus it was possible 

It is of considerable interest that human erythrocyte phosphoglycerides have a similar distribution of plasmalogens and fatty acids to that of platelets (Farquhar, 1962). Although the fatty add composition of PS in the red cell resembles that of the platelet, there is about twice as much PS in the erythrocyte. This may account for the marked clot-promoting effects of lipids and lipoproteins derived from red cells after damage or hemolysis (O Brien, 1959a Shinowara, 1951, 1957, 1961). 

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