Antithrombin

Function Antithrombin (AT) inactivates several enzymes of the coagulation cycle. AT is relatively inactive until it binds the heparan sidechains of the microvasculature. ▪ α-AT contains 4 occupied glycosylation sites and is found in blood palsma. ▪ β-AT contains only 3 occupied glycosylation sites. ▪ AT-I refers to the absorption of thrombin to fibrin. ▪ AT-II and heparin interfere with the interaction of thrombin and fibrinogen. ▪ AT-III inactivates thrombin in plasma. For details see Student Projects for UMass Chemistry 423 Spring 2012-7. ▪ AT-IV becomes activated during blood coagulation. See details for the antithrombin pentasaccharide complex in Molecular Playground/Antithrombin-Heparin. Disease AT deficiency diseases are: Acquired AT deficiency and Inherited AT deficiency. AT deficiency is involved in thrombosis and pulmonary embolism. Relevance AT activity is enhanced upon . Structural highlights The binding of AT to the heparans or the heparin drug is to a core pentasaccharide. The binding induces conformational change of AT.

spinqualitylabelsall models Glycosylated human antithrombin III complex with heparin (in green) (PDB code 3evj) Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

3D structures of antithrombin3D structures of antithrombin

Updated on 22-February-2016

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• Antithrombin
  • 1att – AT-III – bovine
  • 1ant, 2ant – hAT – human
  • 1e05 - hα-AT-III
  • 1e04 – hβ-AT-III
  • 1ath, 2znh, 4eb1 – hAT-III
  • 1dzg, 1oyh, 1t1f, 2beh, 2b4x, 2hij - hAT-III (mutant)
• Antithrombin binary complexes
  • 1azx, 1nq9, 3evj, 1e03 – hAT III + heparin pentasaccharide
  • 1dzh - hAT-III (mutant) + fluorescein
  • 2gd4 - hAT-III (mutant) + coagulation factor X
  • 1br8, 1jvq, 1lk6, 1r1l – hAT-III + peptide
• Antithrombin ternary complexes
  • 1sr5 - hAT-III + prothrombin + heparin heptasaccharide
  • 1tb6 - hAT-III (mutant) + thrombin + heparin polysaccharide
  • 2b5t - AT-III (mutant) + thrombin (mutant) + heparin polysaccharide
  • 3kcg - hAT-III (mutant) + coagulation factor IXa + heparin pentasaccharide