DEFINITION
Antithrombin III is a small protein molecule that inactivates several enzymes of the coagulation system. It is a glycoprotein produced by the liver and consists of 464 aminoacids (m.w.: 58 kD).
CHEMICAL STRUCTURE AND IMAGES
When relevant for the function
- Primary structure
- Secondary structure
- Tertiary structure
- Quaternary structure
Protein Aminoacids Percentage
![](http://flipper.diff.org/static/files/2873/ATIII_827b.gif)
SYNTHESIS AND TURNOVER
mRNA synthesis
protein synthesis
post-translational modifications
degradation
CELLULAR FUNCTIONS
cellular localization,
biological function
![](http://cheappharmacyrx.info/blog/wp-content/uploads/2009/12/87.gif)
A clotting factor is activated when the factor that precedes it in the clotting cascade splits off a protein fragment and thereby exposes an enzymatic center. The latter can again be inactivated physiologically by complexing with antithrombin III (AT III), a circulating glycoprotein. Heparin acts to inhibit clotting by accelerating formation of this complex more than 1000-fold. Heparin is present (together with histamine) in the vesicles of mast cells.
- Enzymes
- Cell signaling and Ligand transport
- Structural proteins
REGULATION
DIAGNOSTIC USE