American Society of Hirudotherapy

Expression and characterization of the N-terminal half of antistasin, an anticoagulant protein derived from the leech Haementeria officinalis

Research article published in Protein Expr Purif (1991)

Last Updated: June 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Preclinical (animal)Genomics & ProteomicsSalivary PharmacologyPalladino LO et al. · Protein Expr Purif, 1991

Abstract

Antistasin, a 15-kDa anticoagulant protein isolated from the salivary glands of the Mexican leech Haementeria officinalis, has been shown to be a potent inhibitor of factor Xa in the blood coagulation cascade. Antistasin possesses a twofold internal homology between the N- and C-terminal halves of the molecule, suggesting a gene duplication event in the evolution of the antistasin gene. This structural feature also suggests that either or both halves of the protein may possess biological activity if expressed as separate domains. Because the N-terminal domain contains a factor Xa P1-reactive site, we chose to express this domain in an insect cell baculovirus expression system. Characterization of this recombinant half antistasin molecule reveals that the N-terminal domain inhibits factor Xa in vitro, with a K(i) of 1.7 nM.

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

Publication typeJournal Article
Indexed MeSH termsAmino Acid SequenceAnimalsAnticoagulantsBaculoviridaeBase SequenceCloning, MolecularDNAFactor Xa InhibitorsGene ExpressionInvertebrate HormonesLeechesMolecular Sequence Data

Summary

Antistasin, a 15-kDa anticoagulant protein isolated from the salivary glands of the Mexican leech Haementeria officinalis, has been shown to be a potent inhibitor of factor Xa in the blood coagulation cascade.

Why This Matters for Hirudotherapy

This study expressed the N-terminal half of antistasin, a 15-kDa anticoagulant from the salivary glands of the Mexican leech Haementeria officinalis and a potent factor Xa inhibitor, in an insect-cell baculovirus system and showed that this isolated domain, which carries the factor Xa P1-reactive site, inhibits factor Xa in vitro with a Ki of 1.7 nM. It is a foundational entry in the leech-secretome drug-discovery story, demonstrating that a single recombinant domain of a leech anticoagulant retains targeted, high-affinity factor Xa inhibition and supporting the molecule's proposed evolution by internal gene duplication. As an in-vitro biochemical characterization of a recombinant protein, it establishes molecular activity only; it includes no animal or human data and makes no claim about clinical anticoagulation, dosing, or safety, so it speaks to drug-discovery potential rather than therapeutic use.

Citation

Expression and characterization of the N-terminal half of antistasin, an anticoagulant protein derived from the leech Haementeria officinalis.

Palladino LO et al. · Protein Expr Purif, 1991

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