Sphingosine
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Sphingosine (2-amino-4-octadecene-1,3-diol) is an 18-carbon amino alcohol with an unsaturated hydrocarbon chain, which forms a primary part of sphingolipids, a class of cell membrane lipids that include sphingomyelin, an important phospholipid. Sphingosine can be phosphorylated in vivo via two kinases, sphingosine kinase type 1 and sphingosine kinase type 2.
Sphingolipid metabolites, such as ceramide, sphingosine and sphingosine-1-phosphate, are lipid second messengers involved in diverse cellular processeses.
[edit] Synthesis
Sphingosine is synthesized from palmitoyl CoA and serine in a condensation required to yield dehydrosphingosine. Dehydrosphingosine is then reduced by NADPH to dihydrosphingosine, and finally oxidized by FAD to sphingosine.
[edit] External links
N. S. Radin, in The Biochemical Journal 371:243-256 (2003)
This section says that dehydrosphingosine (usually called 3-ketosphinganine) is enzymatically converted to sphingosine but it isn't. The carbonyl group is reduced, forming dihydrosphingosine (sphinganine), which reacts with a fatty acid-CoA, forming dihydroceramide, which is then dehydrogenated to form the trans double bond at carbons 4 and 5. This is ceramide, which can be hydrolyzed to liberate sphingosine and fatty acid.
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