Ceramides
Ceramides are a group of sphingolipids with the general structure shown as part of sphingomyelin here. Ceramides are made either as part of sphingolipid biosynthesis or degradation.

Ceramides are synthesized by attachment of an acyl group to the amino alcohols sphingosine, dihydrosphingosine (see here), or their derivatives.

Cerebrosides are made from ceramides by attachment of a sugar group to the ceramide moiety (Figure 19.14).

Sphingomyelin is made by transferring choline from phosphatidylcholine to a ceramide (Figure 19.13)

Ceramides are broken down by the enzyme ceramidase. Deficiency of ceramidase leads to accumulation of ceramides, which results in deformed joints and problems with heart, lungs, and lymph nodes. The syndrome is usually fatal within a few years of birth.

See also: Sphinglipids, Table 19.1