Sphingosine, biosynthesis

The major sphingosine base found in animal tissues is D-erythro-l, 3 dihydroxy-2 amino octadecene-4 or Chs sphingosine. This material is usually accompanied by small amounts of its saturated derivative, di-hydrosphingosine. Early studios designed to elucidate the pathway of sphingosine biosynthesis employed intraperitoneal administration of various carbon-14 labeled precursors in young rats (Zabin and -Mead, 1953,... 

Figure 9.18 Structures of sphinogosine (A), a sphingomyelin (B), a glucocerebroside (C), and a ganglioside (D). In the last, stearic acid is attached to the -NH2 residue of sphingosine. The structure shown represents a GMj ganglioside. (Parts A, B, C reproduced by permission from Diem K, Lentner C. Scientific Tables. Basel Ciba-Geigy, 1971, p. 376 part D reproduced with permission from Fishman PH, Brady RO. Biosynthesis and function of gangliosides. Science 194 906-915, 1976.

Purines and pyrimidines are derived largely from amino acids. The biosynthesis of these precursors of DNA, RNA, and numerous coenzymes will be discussed in detail in Chapter 25. The reactive terminus of sphingosine, an intermediate in the synthesis of sphingolipids, comes from serine. Histamine, a potent vasodilator, is derived from histidine by decarboxylation. Tyrosine is a precursor of the hormones thyroxine (tetraiodothyronine) and epinephrine and of melanin, a complex polymeric pigment. The neurotransmitter serotonin (5-hydroxytryptamine) and the nicotinamide ring of NAD + are synthesized from tryptophan. Let us now consider in more detail three particularly important biochemicals derived from amino acids. 

The precursors in the biosynthesis of sphingosines51-53 are, according to Brady and associates,54 L-serine (28) and palmitaldehyde (29). These compounds give dihydrosphingosine (30), which is catalytically dehydrogenated by flavoprotein to give sphingosine (31). 

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