3-keto-Dihydrosphingosine is a vital intermediate in the biosynthesis of ceramides.1,2 3-keto-Dihydrosphingosine is formed by the condensation of L-serine and palmitoyl-CoA by the serine palmitoyl transferase enzyme.3 It is then reduced to dihydrosphingosine, converted to ceramide, and eventually synthesized into many types of sphingolipids. C18-ketodihydrosphingosine is the major sphingolipid precursor in the early and intermediate stages of cell life with C20-ketodihydrosphingosine as a minor component. Towards the end of the cell’s life the ratio of C18 to C20 ketodihydrosphingosine becomes more equal. It seems to be a critical regulating step in the availability of sphingolipids in cells. Vitamin K deficiency results in the inactivation of the serine palmitoyl transferase enzyme causing a resultant shortage of sphingolipids.
