Glycolipid

Chemical structure of glycolipids

Glycolipids are lipids with a carbohydrate attached. Their role is to provide energy and also serve as markers for cellular recognition.

Metabolism

They occur where a carbohydrate chain is associated with phospholipids on the exoplasmic surface of the cell membrane. The carbohydrates are found on the outer surface of all eukaryotic cell membranes. The carbohydrate structure of the glycolipid is controlled by the glycosyltransferases that add the lipids and glycosylhydrolases that modify the glycan after addition.

They extend from the phospholipid bilayer into the aqueous environment outside the cell where it acts as a recognition site for specific chemicals as well as helping to maintain the stability of the membrane and attaching cells to one another to form tissues.

Sphingolipidoses can be associated with defects in metabolism.

Types of glycolipids

The following is an incomplete listing of glycolipid types.

This list is incomplete; you can help by expanding it.

• Glyceroglycolipids
  • Galactolipids
  • Sulfolipids (SQDG)
• Glycosphingolipids
  • Cerebrosides
    • Galactocerebrosides
    • Glucocerebrosides
    • Sulfatides
  • Gangliosides (the most complex animal glycolipids; contain negatively charged oligosacchrides with one or more sialic acid residues; more than 200 different gangliosides have been identified; they are most abundant in nerve cells)
  • Globosides
  • Glycophosphosphingolipids (complex glycophospholipids from fungi, including yeasts, and in plants, where they were originally called "phytoglycolipids" by Herbert Carter, et al., may comprise as complicated a set of compounds as the negatively charged gangliosides in animals. The head group of a glycolipid is composed of sugars.
• Glycosylphosphatidylinositols

See also

• Glycocalyx
• Glycoproteins
• Niemann Pick disease Type C

External links

• Glycolipids at the US National Library of Medicine Medical Subject Headings (MeSH)