Antithrombin-III
血漿中に含まれる4種類のトロンビン阻害物質のうちの主要なもの（他にα2-マクログロブリン、ヘパリン補因子2、α1-アンチトリプシン）。硫酸化グリコサミノグリカン（ヘパリン）がアンチトロンビンの陽電荷部位に結合し、立体構造が変化してトロンビンとの相互作用を促進する。したがって、ヘパリンの抗凝固作用は陽電荷をもつプロタミンにより阻害される。
Short name=ATIII
Alternative name(s):
Serpin C1
- Function
- Most important serine protease inhibitor in plasma that regulates the blood coagulation cascade. AT-III inhibits thrombin, matriptase-3/TMPRSS7, as well as factors IXa, Xa and XIa. Its inhibitory activity is greatly enhanced in the presence of heparin. Ref.18
- Subunit structure
- Forms protease inhibiting heterodimer with TMPRSS7.
- Subcellular location
- Secreted › extracellular space.
- Tissue specificity
- Found in plasma.
- Post-translational modification
- Phosphorylation sites are present in the extracellular medium.
- Involvement in disease
- Antithrombin III deficiency (AT3D) [MIM:613118]: An important risk factor for hereditary thrombophilia, a hemostatic disorder characterized by a tendency to recurrent thrombosis. Antithrombin-III deficiency is classified into 4 types. Type I: characterized by a 50% decrease in antigenic and functional levels. Type II: has defects affecting the thrombin-binding domain. Type III: alteration of the heparin-binding domain. Plasma AT-III antigen levels are normal in type II and III. Type IV: consists of miscellaneous group of unclassifiable mutations.
- Note: The disease is caused by mutations affecting the gene represented in this entry. Ref.3 Ref.12 Ref.13 Ref.32 Ref.33 Ref.34 Ref.35 Ref.36 Ref.37 Ref.38 Ref.39 Ref.41 Ref.42 Ref.43 Ref.44 Ref.45 Ref.46 Ref.47 Ref.48 Ref.49 Ref.50 Ref.51 Ref.52 Ref.53 Ref.54 Ref.55 Ref.56 Ref.57 Ref.58 Ref.60 Ref.61 Ref.62 Ref.63 Ref.64 Ref.65 Ref.66 Ref.67
- Sequence similarities
- Belongs to the serpin family.
- Mass spectrometry
- Molecular mass is 57863 Da from positions 33 - 464. Determined by ESI. Ref.13 / Molecular mass is 57911 Da from positions 33 - 464. Determined by ESI. Variant Thr-414. Ref.13
