Sphing-4-enine

Even though it is commonly referred to as sphingosine, its proper chemical name is D-erythro-1,3-dihydroxy-4, 5-trans-octadecene. Other satisfactory names are rran.v-4-sphingosine, sphing-4-enine, or sphingenine in any event, all the naturally occurring sphingolipids contain only the D-erythro form. 

C12 B-D-Glucosyl Ceramide GlcCer(dl8 l/12 0) N-(dodecanoyl)-l-p-glucosyl-sphing-4-enine... 

FIGURE 9.4 The structures of the principal sphingolipids. (a) Sphingosine (Sphing-4-enine). (b) Ceramide (N-acyl-sphmg-4-enme). (c) Sphingomyelin (N-acyTsphing-4-enine-l-phosphocholine). 

The first intermediate in sphing-4-enine biosynthesis, catalyzed by microsomal enzymes, is l-hydroxy-2S-amino-3-oxooctadecane (3-dehydrosphinganine) (Stoffel et al., 1967 Braun and Snell, 1968). 

This compound also could be synthesized by Mendershausen and Sweeley (1969) and Gaver and Sweeley (1966). In vivo it is formed from 1-serine- and palmityl-CoA. The reaction requires pyridoxal phosphate. The next step is catalyzed by a S-3-dehydrosphinganine /3-NADPH oxidoreductase (Stoffel et al., 1968), and the major product is sphinganine (Braun et al., 1970 Morrell and Radin, 1970b). Starting with stearoyl-CoA, eicosasphinganine is the main product. The final introduction of a carbon double bond yields sphing-4-enine ... 

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