Hirudin — das primäre Antikoagulans
Der stärkste bekannte natürliche Thrombin-Inhibitor
Hirudin binds thrombin with K_d ≈ 20 femtomolar — a million times tighter than heparin's antithrombin-mediated grip. Der Blutegel evolved die am stärksten potent natural Thrombin-Inhibitor known to biology.Markwardt F 1991 (Pharmacology & Therapeutics, grundlegende Übersicht)
Zuletzt aktualisiert: June 18, 2026
Hirudin is a 65-amino-acid peptide that functions as die am stärksten potent natural Thrombin-Inhibitor known to science. This single molecule inspired the development of three FDA-zugelassenen Antikoagulans drugs and continues to serve as a model for pharmaceutical research.
Molekulares Profil
- Size: 65 Aminosäuren, molecular weight ~7 kDa
- Mechanismus: Direct Thrombin-Inhibitor with 1:1 stoichiometry
- Potency: Inhibition constant (Ki) ≈ 21 fM (2 × 10⁻¹⁴ M) — eine der tightest Protein–Protein interactions measured in nature
- Struktur: Compact N-terminal domain (residues 1–48) stabilized by 3 disulfide bonds + flexible C-terminal tail (residues 49–65)
- Entdeckung: First identified by John B. Haycraft (1884); isolated and characterized by Fritz Markwardt (1957)
Wirkmechanismus
Hirudin achieves thrombin inhibition through a bivalent binding mechanism — it simultaneously binds:
- Active site of thrombin (N-terminal domain of hirudin, residues 1–48)
- Exosite I (fibrinogen recognition exosite) (C-terminal tail of hirudin, residues 49–65)
This dual-site binding results in complete bivalent inhibition. Unlike heparin-based Antikoagulantien, hirudin acts directly on thrombin without requiring antithrombin as a cofactor, and es ist not neutralized by platelet factor 4 (PF4).
Hirudin vs. Heparin
| Eigenschaft | Hirudin | Heparin (UFH) |
|---|---|---|
| Mechanismus | Direkter Thrombin-Inhibitor | Indirect (requires antithrombin cofactor) |
| PF4 resistance | Not neutralized by PF4 | Neutralized by PF4 (HIT risk) |
| Gerinnsel-gebundenes Thrombin | Inhibits clot-bound thrombin | Cannot reach clot-bound thrombin |
| Monitoring | aPTT or ECT | aPTT, anti-Xa |
| Half-life (IV) | ~1–2 Stunden | ~1–1,5 Stunden (dosisabhängig) |
| Antidot | Keine (kein spezifisches Antidot) | Protaminsulfat |
| Clearance | Renal (Dosisanpassung bei Niereninsuffizienz) | Retikuloendothelial + renal |
Isoformen
Different Hirudo species produce distinct hirudin isoforms with slightly varying structures and potencies:
| Isoform | Quelle | Anmerkungen |
|---|---|---|
| HV1 | H. medicinalis | Die meisten extensively studied; template for recombinant drugs |
| HV2 | H. verbana | Slight sequence variation; ähnliche Potenz |
| HV3 | H. orientalis | Östliche Art; eigenständiges pharmakokinetisches Profil |
Historische Zeitleiste
| Jahr | Ereignis |
|---|---|
| 1884 | John B. Haycraft identifies Antikoagulans activity in Blutegelextrakt |
| 1957 | Fritz Markwardt isoliert und charakterisiert Hirudin |
| 1984 | Dodt et al. determine hirudin gene sequence, enabling recombinant production |
| 1998 | Lepirudin (recombinant hirudin) receives FDA-Zulassung for HIT |
| 2000 | Bivalirudin (synthetischer direkter Thrombin-Inhibitor), zugelassen für PCI-Antikoagulation |
| 2003 | Desirudin zugelassen zur TVT-Prophylaxe |
| 2012 | Lepirudin eingestellt (ersetzt durch Bivalirudin und Argatroban) |
Pharmazeutisches Erbe
Hirudin Forschung directly led to the development of three FDA-zugelassenen Antikoagulans drugs:
| Wirkstoff | Typ | FDA-zugelassen | Indikation | Status |
|---|---|---|---|---|
| Lepirudin (Refludan) | Rekombinantes Hirudin | 1998 | HIT Typ II | 2012 eingestellt |
| Desirudin (Iprivask) | Rekombinantes Hirudin | 2003 | TVT-Prophylaxe (Hüftgelenkersatz) | Verfügbar |
| Bivalirudin (Angiomax) | Synthetisches DTI (hirudin-inspired) | 2000 | Antikoagulation während PCI | Aktiv, weit verbreitet |
Pharmazeutische Translation
Bildungs-Haftungsausschluss
Verwandte Ressourcen
Speicheldrüsenkomplex
440+ Proteine im Blutegel-SDS identifiziert — Naturapotheke.
Antikoagulationswirkstoffe
Factor Xa inhibitors, calin, and the multi-target Antikoagulans system.
Arzneimittelentwicklung
Von Blutegel-Verbindungen zu FDA-zugelassenen Arzneimitteln.
Hirudin in the Compound Registry
Hirudin's full entry in the 107-compound catalogue with PMIDs, PDB IDs, and FDA-derivative cross-refs.
Compound Coverage Map
All 107 catalogued leech compounds with evidence-tier filtering.