cerebrosidien

Cerebrosiden, also called cerebroside in English, is a class of neutral glycosphingolipids composed of a ceramide backbone linked to a single sugar residue, either glucose or galactose. The two main forms are glucosylceramide (glucosylceramide) and galactosylceramide (galactocerebroside). They are widespread in cell membranes, with particularly high abundance in nervous tissue where galactosylceramide is a major component of myelin.

Biosynthesis occurs in the Golgi apparatus. Glucosylceramide is formed by the enzyme ceramide glucosyltransferase, which transfers a glucose moiety to ceramide. Galactosylceramide is produced by galactosyltransferase, which transfers galactose to ceramide. Degradation takes place in lysosomes: glucosylceramide is hydrolyzed by glucocerebrosidase to yield ceramide and glucose, while galactosylceramide is hydrolyzed by galactocerebrosidase to produce ceramide and galactose.

Clinical relevance is notable in lysosomal storage disorders. Deficiency of glucocerebrosidase leads to Gaucher disease, characterized by accumulation of glucosylceramide in macrophages and various organs. Deficiency of galactocerebrosidase causes Krabbe disease, marked by buildup of galactosylceramide and psychosine, with demyelination and neurological impairment. These conditions illustrate the importance of cerebrosides in lipid metabolism and nervous system integrity.

Functions attributed to cerebrosides include stabilizing cell membranes and lipid rafts, contributing to the structure and compaction of myelin, and participating in cell–cell recognition and signaling via their glycan portions. They also serve as substrates and intermediates in broader sphingolipid metabolism.