Antithrombin monomer.jpeg
Available structures

IdentifiersSERPINC1, AT3, AT3D, ATIII, THPH7, serpin family C member 1, ATIII-R2, ATIII-T2, ATIII-T1External IDs107300 88095 20139 SERPINC1
Gene location (Human)
Chromosome 1 (human)
Chr.Chromosome 1 (human)[1]
Chromosome 1 (human)
Genomic location for SERPINC1
Genomic location for SERPINC1
Band1q25.1Start173,903,804 bp[1]
End173,917,378 bp[1]
RNA expression pattern
PBB GE SERPINC1 210049 at fs.png
More reference expression data


Chr 1: 160.98 – 161.01 MbPubMed search[3][4]Wikidata
View/Edit HumanView/Edit Mouse

Antithrombin (AT) is a small protein molecule that inactivates several enzymes of the coagulation system. Antithrombin is a glycoprotein produced by the liver and consists of 432 amino acids. It contains three disulfide bonds and a total of four possible glycosylation sites. α-Antithrombin is the dominant form of antithrombin found in blood plasma and has an oligosaccharide occupying each of its four glycosylation sites. A single glycosylation site remains consistently un-occupied in the minor form of antithrombin, β-antithrombin.[5] Its activity is increased manyfold by the anticoagulant drug heparin, which enhances the binding of antithrombin to factor IIa (Thrombin) and factor Xa.[6]


Antithrombin is also termed Antithrombin III (AT III). The designations Antithrombin I through to Antithrombin IV originate in early studies carried out in the 1950s by Seegers, Johnson and Fell.[7]

Antithrombin I (AT I) refers to the absorption of thrombin onto fibrin after thrombin has activated fibrinogen. Antithrombin II (AT II) refers to a cofactor in plasma, which together with heparin interferes with the interaction of thrombin and fibrinogen. Antithrombin III (AT III) refers to a substance in plasma that inactivates thrombin. Antithrombin IV (AT IV) refers to an antithrombin that becomes activated during and shortly after blood coagulation.[8] Only AT III and possibly AT I are medically significant. AT III is generally referred to solely as "Antithrombin" and it is Antithrombin III that is discussed in this article.

Other Languages
Cymraeg: SERPINC1
español: Antitrombina
français: Antithrombine
galego: Antitrombina
hrvatski: Antitrombin
Bahasa Indonesia: Anti-trombin
italiano: Antitrombina
Nederlands: Antitrombine
português: Antitrombina
русский: Антитромбин
српски / srpski: Antitrombin
srpskohrvatski / српскохрватски: Antitrombin
svenska: Antitrombin
українська: Антитромбін