Home > Von Willebrand factor

1 Biochemistry

1.1 Synthesis

vWF is a large multimeric glycoprotein present in blood plasma and produced constitutively in endothelium (in the Weibel-Palade bodies), megakaryocytes (α-granules of platelets), and subendothelial connective tissue.

1.2 Structure

The basic vWF monomer is a 2050 amino acidIn chemistry, an amino acid is any molecule that contains both amino and carboxylic acid functional groups. In biochemistry, this shorter and more general term is frequently used to refer to alpha amino acids: those amino acids in which the amino and carb protein. Every monomer contains a number of specific domains with a specific function; elements of note are:

• the D'/D3 domain, which binds to Factor VIII
• the A1 domain, which binds to:
  • platelet gp1b-receptor
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• the A3 domain, which binds to collagen
• the C1 domain, in which the RArginine is one of the 20 most common natural amino acids. Is has guanidino side chain functional group. In non-hepatic tissues, arginine can be biosynthesized by the ornithine cycle (or urea cycle). Even so, arginine is often classed as one of the 10 ess GThis is an article about Glycine, the amino acid. For the plant genus containing the soybean, see Glycine (plant) Glycine is a nonpolar amino acid. It is the simplest of the 20 natural amino acids; its side chain is a hydrogen atom. Because there is a sec DAsparagine is one of the 20 most common natural amino acids on Earth. It has carboxamide as the side chain's functional group. A byproduct of the breakdown of asparagine (asparagine-amino-succinic-acid monoamide) is also blamed for the smell in some peopl domain binds to platelet integrinAn integrin or integrin receptor is a receptor in the plasma membrane of cells. Integrins play an important role in: Integration of the cell into the surrounding tissue by cell-cell-interaction adhesive interaction Embryonal development Tumor development α_IIbβ₃ when this is activated
• the "cysteine knot" domain (at the C-terminal end of the protein), which vWF shares with platelet-derived growth factorPlatelet-derived growth factor PDGF is one of the numerous proteins that regulate cell growth and division. There are many known forms of PDGF ligands and receptors. The important ones are ligands A and B, and receptors alpha and beta. PDGF are responsibl (PDGF), transforming growth factor -β (TGFβ) and β- human chorionic gonadotrophin (βHCG, of pregnancy test fame).

Monomers are subsequently N-glycosylated, arranged into dimers in the endoplasmic reticulum and into multimers in the Golgi apparatus by crosslinking of cysteine residues via disulfide bonds. With respect to the glycosylation, vWF is one of the few proteins that carry blood group antigens (ABO system).

Multimers of vWF can be extremely large, >20,000 kDa, and consist of over 80 subunits of 250 kDa each. Only the large multimers are functional. Some cleavage products that result from vWF production are also secreted but probably serve no function.