Glycoproteins and GAGs

  1. glycosly transferase is the enzyme that
    enlongates the glycoproteins that are attached to the membrane of the golgi
  2. proteins that will be exported, incorporated into the membrane or going to lysosome will contain what
    a hydrophobic signal sequence on the N-terminal

    this acts to target the protein
  3. I-cell disease (inclusion body disease) is caused by a deficiency of__________, an enzyme normally found in the cis-Golgi
    N-acetylglucosamine phosphotransferase
  4. What are the three representative sugars found in GAGs?
    • glucosamine
    • D-glucuronic acid
    • L-Iduronic acid
  5. what are the 2 adhesive proteins found in the ECM
    laminin, fibronectins
  6. Most of the GAGs are sulfonated but one is not...which is this one?
    Hyaluronic acid
  7. what is the most abundant GAG in the body?
    Chondroitin 4 and 6 sulfates
  8. found primarily in the skin, but also in blood vessels and heard valves
    Dermatan sulfate
  9. found primarily in the corner of eye, playing a role in corneal transparency
    keratan sulfates
  10. found in cartilage, tendons, ligaments, aorta and other part of large aggregates
    chondroitin-4 and 6 sulfates
  11. heparin binds to _____ and enhances its activity as an anticoagulant (inhibition of thrombin)
    anti-thrombin III
  12. anti-throbin III is a ______ inhibitor
  13. True/False: hylauronic acid is covalently bound to proteins

    bound but NOT covalently
  14. difference between heparin and heparan
    heparin is found intracellularly

    heparan is a component of cell surfaces
  15. proteoglycans are proteins that are covalently linked to ______
  16. what is the most common linkage between the 
    core protein and the GAG
    O-glycosidic bond between the xylose on the trihexoside (Gal-Gal-Xyl) and a serine residue in the protein
  17. The core proteins of the proteoglycans are synthesized in the ____ and how do you know this?

    because they are exported to the outside of the cell
  18. where does chain elongation, chain termination, and other modifications (additon of sulfates and epimerization of sugars) occur?
    in the Golgi
  19. what is called when the proteoglycan (core proteins linked to GAG’s) units interact through ionic association
    formation of proteoglycan aggregates.
  20. the proteoglycan units in the aggregates are associated through ionic interaction (non covalent) with_____ ____
    hylauronic acid
  21. where does GAG breakdown occur?
  22. what two enzymes are required in the breakdown of GAGs
    endoglycosidases and exoglycosidases
  23. Mutations associated with the lysosomal hydrolases are known as
  24. the identification of the ____ _____ can indicate which specific enzyme is deficient or absent in a mucopolysaccharidoses
    terminal sugar
  25. ______ is secreted by some bacteria. 

    This enzyme helps the bacteria spread by enzymatically

    loosening the connective tissue matrix.
  26. Hyaluronidase has also been used to help promote the absorption and dispersion of what?

    loosen the CT matrix so drugs can get in
Card Set
Glycoproteins and GAGs
Biochem Exam 2 Material