Figure 1.

Biosynthesis and degradation of sulfatide. GalC is synthesized in the endoplasmic reticulum by the transfer of galactose to ceramide, which is catalyzed by the UDP-galactose:ceramide galactosyltransferase (EC 2.4.1.45). In the Golgi appartus, GalC is converted to sulfatide by the transfer of a sulfate group from PAPS to the galactose residue, which is catalyzed by the Gal3st1 (EC 2.8.2.11). Degradation of sulfatide in lysosomes starts with the hydrolysis of the sulfate residue by ASA (EC 3.1.6.8).