Fibrinogen degradation by hementin, a fibrinogenolytic anticoagulant from the salivary glands of the leech Haementeria ghilianii

The leech Haementeria ghilianii contains the anticoagulant hementin in its salivary glands, which renders ingested blood incoagulable. The loss of thrombin-coagulability of human fibrinogen, plasma, and blood was dependent on both dose and time, and it was attributable to direct proteolytic degradation of fibrinogen (Mr 340,000) by hementin. Using purified fibrinogen as the substrate, it was demonstrated that the enzyme cleaved with equal probability either through all three chains in the connector region between the D and E structural domains or in the COOH-terminal of the A alpha chain. The degradation pattern of fibrinogen in blood and purified counterpart was the same in respect to the types of degradation products formed and the rate of proteolysis. Three pairs of fibrinogen degradation products characterized by Mr were distinguished: 320,000 and 300,000, 225,000 and 200,000, 157,000 and 132,000. In each pair, the heavier product had the intact COOH-terminals of the A alpha, B beta, and gamma chains. Of special interest was the derivative of Mr 225,000 because it contained the intact A alpha, B beta, and gamma chains of the original fibrinogen. Hementin cleaved non-cross-linked and cross-linked fibrin clots; however, the rate of proteolysis was much slower than that of fibrinogen. Individual carboxymethylated chains of fibrinogen were not degraded by the enzyme. Hementin abolished coagulability of fibrinogen by a limited proteolysis that disassembled functionally bivalent polymerization sites. In addition, fibrin clot formation was inhibited by fibrinogen fragments generated by hementin. The enzyme appeared to have a unique and limited specificity for a few peptide bonds projected in the tertiary structure of the native fibrinogen molecule.

Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.

Peer-reviewed clinical and outcomes research relevant to medicinal leech therapy and its biology. Indexed in PubMed and verified against the NCBI record.

Leech-derived molecules this paper discusses, each with a full profile in the ASH compound registry:

Узнайте, как это исследование связано с клинической практикой

More peer-reviewed studies in Клинические исследования.

• Leech Therapy for Knee Osteoarthritis — The Landmark RCT — Michalsen et al. (2003)
• Leech-Assisted Flap Salvage — Systematic Review of 277 Cases — Whitaker et al. (2012)
• Effects of hirudotherapy on liver functions, lipid profile, and insulin sensitivity in rats with metabolic syndrome — Bilden A et al. (2026)
• HIRUDOTHERAPY IN PRESBYACUZIS PRAECOX IN CLEAN-UP WORKERS AFTER THE CHORNOBYL ACCIDENT DURING THE POST-CATASTROPHE YEARS — Zabolotnyi D, Mishchanchuk N (2019)
• Wound healing potential of bark paste of Pongamia pinnata along with hirudotherapy: A case report — Balasooriya D, Karunarathna C, Uluwaduge I (2021)
• AIF-1 and RNASET2 Play Complementary Roles in the Innate Immune Response of Medicinal Leech — Baranzini N et al. (2019)
• Study on the effect of medicinal leech therapy (Hirudo medicinalis) on full-thickness excisional wound healing in the animal model — Zakian A et al. (2022)
• [Hirudo medicinalis-leech applications in plastic and reconstructive microsurgery--a literature review] — Knobloch K et al. (2007)
• The duration of rest and feeding greatly affects the re-breeding of ectoparasites: Hirudo verbana, Hirudo medicinalis and Hirudo orientalis — Aminov R, Frolov A, Aminova A (2022)
• Recombinant hirudin in clinical practice: focus on lepirudin — Greinacher A, Lubenow N (2001)

Browse all ASH-analysed research →