Isolation and structural characterization of a potent inhibitor of coagulation factor Xa from the leech Haementeria ghilianii
Research article published in Thrombosis and haemostasis (1989)
Abstract
The present work reports the discovery and characterization of an anticoagulant protein in the salivary gland of the giant bloodsucking leech, H. ghilianii, which is a specific and potent inhibitor of coagulation factor Xa. The inhibitor, purified to homogeneity, displayed subnanomolar inhibition of bovine factor Xa and had a molecular weight of approximately 15,000 as deduced by denaturing SDS-PAGE. The amino acid sequence of the first 43 residues of the H. ghilianii derived inhibitor displayed a striking homology to antistasin, the recently described subnanomolar inhibitor of factor Xa isolated from the Mexican leech, H. officinalis. Antisera prepared to antistasin cross-reacted with the H. ghilianii protein in Western Blot analysis. These data indicate that the giant Amazonian leech, H. ghilianii, and the smaller Mexican leech, H. officinalis, have similar proteins which disrupt the normal hemostatic clotting mechanisms in their mammalian host's blood.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Summary
Isolation and structural characterization of a potent inhibitor of coagulation factor Xa from the leech Haementeria ghilianii.
Why This Matters for Hirudotherapy
This study reports the isolation and characterization of a novel anticoagulant protein from the salivary glands of the giant Amazonian leech Haementeria ghilianii, showing that it is a specific, potent inhibitor of coagulation factor Xa with subnanomolar inhibitory activity and ~15 kDa molecular weight, and that its N-terminal sequence closely resembles antistasin from H. officinalis. For ASH and hirudotherapy, this work is directly relevant: it expands the known repertoire of leech-secreted anticoagulants that disarm host hemostasis, the same biological principle that makes leech secretome components (e.g., hirudin) valuable as therapeutic anticoagulants and as starting points for drug development. Identifying additional leech-derived factor Xa inhibitors strengthens the scientific rationale for continued study of the leech secretome. The honest caveat is that this is an in vitro biochemical isolation and characterization study reporting inhibition of bovine factor Xa; it does not demonstrate therapeutic efficacy, pharmacokinetics, or safety in humans.
Citation
Added to ASH library: May 27, 2026 · Site last updated: June 18, 2026