3-Keto-Dihydrosphingosines

3-Keto-dihydrosphingosine is a vital intermediate in the biosynthesis of ceramides.1,2 It 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-keto-dihydrosphingosine is the major sphingolipid precursor in the early and intermediate stages of cell life, while C20-keto-dihydrosphingosine is a minor component. Towards the end of the cell’s life the ratio of C18 to C20 keto-dihydrosphingosine becomes more equal. 3-Keto-dihydrosphingosine is 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.

References:

  1. N. Bartke and Y. Hannun “Bioactive sphingolipids: metabolism and function” Journal of Lipid Research, Vol. 50 pp. S91-S96, 2009
  2. G. Jenkins and Y. Hannun “Role for de Novo Sphingoid Base Biosynthesis in the Heat-induced Transient Cell Cycle Arrest of Saccharomyces cerevisiae” Journal of Biological Chemistry, Vol. 276 pp. 8574-8581, 2001
  3. A. Batheja et al. “Characterization of Serine Palmitoyltransferase in Normal Human Tissues” Journal of Histochemistry and Cytochemistry, Vol. 51 pp. 687-696, 2003