Heparan Sulfate - HS Structure and Differences From Heparin

HS Structure and Differences From Heparin

Heparan sulfate is a member of the glycosaminoglycan family of carbohydrates and is very closely related in structure to heparin. Both consist of a variably sulfated repeating disaccharide unit. The main disaccharide units that occur in heparan sulfate and heparin are shown below.

The most common disaccharide unit within heparan sulfate is composed of a glucuronic acid (GlcA) linked to N-acetylglucosamine (GlcNAc) typically making up around 50% of the total disaccharide units. Compare this to heparin where IdoA(2S)-GlcNS(6S) makes up 85% of heparins from beef lung and about 75% of those from porcine intestinal mucosa. Problems arise when defining hybrid GAGs that contain both 'heparin-like' and 'HS-like' structures. It has been suggested that a GAG should qualify as heparin only if its content of N-sulfate groups largely exceeds that of N-acetyl groups and the concentration of O-sulfate groups exceeds those of N-sulfate.

Not shown below are the rare disaccharides containing a 3-O-sulfated glucosamine (GlcNS(3S,6S) or a free amine group (GlcNH3+). Under physiological conditions the ester and amide sulfate groups are deprotonated and attract positively charged counterions to form a salt. It is in this form that HS is thought to exist at the cell surface.

  • GlcA-GlcNAc
  • GlcA-GlcNS
  • IdoA-GlcNS
  • IdoA(2S)-GlcNS
  • IdoA-GlcNS(6S)
  • IdoA(2S)-GlcNS(6S)

Read more about this topic:  Heparan Sulfate

Famous quotes containing the words structure and/or differences:

    If rightly made, a boat would be a sort of amphibious animal, a creature of two elements, related by one half its structure to some swift and shapely fish, and by the other to some strong-winged and graceful bird.
    Henry David Thoreau (1817–1862)

    What we have to do ... is to find a way to celebrate our diversity and debate our differences without fracturing our communities.
    Hillary Rodham Clinton (b. 1947)