Structure of plasma sphingadienine.

The dienic long-chain base (sphingadienine) of human plasma sphingomyelins has been identified as d-erythro-1,3-dihydroxy-2-amino-4-trans-14-cis-octadecadiene. A similar sphingosine was also detected in plasma sphingomyelins of rat, rabbit, and cat. The key reaction in the structural studies was partial reduction of sphingadienine with hydrazine to cis-14-sphingenine and 4-sphingenine.