The major sulphated glycolipid in mammalian tissues is galactosylceramide with a sulphate attached to the 3-position of the sugar (Table 6.7). It is commonly known as sulphatide. However, various other sulphated glycolipids (e.g. lactosylceramide
Fig. 7.16 Phosphoadenosine phosphosulphate: the donor of sulphate groups.
sulphate) have also been detected in small amounts in different animal tissues.
Sulphatide is an important constituent of the myelin sheath of nervous tissue and the incorporation of radioactive sulphate into the sulphatide molecule has been used to study myelination. The donor of the sulphate group is the complex nucleotide 3'-phosphoadenosine 5'-phosphosul-phate, usually abbreviated in scientific papers to PAPS (Fig. 7.16). PAPS itself is produced from ATP in two steps via an adenosine 5'-phosphosulphate (APS) intermediate. The synthesis of sulphatide is catalysed by a sulphotransferase, which has been detected in the microsomal fraction from a number of tissues:
galactosylceramide + PAPS ^
3-sulpho-galactosylceramide + PAP
Was this article helpful?