American Society of Hirudotherapy

Isolation and characterization of hirustasin, an antistasin-type serine-proteinase inhibitor from the medical leech Hirudo medicinalis

Comparative study published in Eur J Biochem (1994)

Last Updated: June 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Observational studyGenomics & ProteomicsSalivary PharmacologySöllner C et al. · Eur J Biochem, 1994

Abstract

Antistasin, a potent inhibitor of the blood coagulation factor Xa, is the prototype of a novel family of serine-proteinase inhibitors. We have now isolated, sequenced and characterized an antistasin-type inhibitor from the medical leech Hirudo medicinalis. Hirustasin (Hirudo antistasin) was purified to apparent homogeneity by cation-exchange and affinity chromatography. Amino acid sequencing of the 55 amino acid protein (M(r) 5866) revealed that hirustasin is the only antistasin-type protein known to consist of one domain only; 27% and 32% sequence identity was found to the first and second domains of antistasin, respectively, and a nearly exact conservation of the spacing of the ten cysteine residues. Hirustasin is the first inhibitor of tissue kallikrein identified in leeches, and is also a tight-binding inhibitor of trypsin, chymotrypsin and neutrophil cathepsin G. However, despite the high similarity to antistasin, particularly in the vicinity of the putative reactive-site peptide bond, hirustasin neither inhibits blood coagulation in vitro nor amidolytic activity of isolated factor Xa. Thus, structural elements other than the reactive site sequence significantly influence the specificity of antistasin-type proteinase inhibitors.

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

Publication typeComparative StudyJournal ArticleResearch Support, Non-U.S. Gov't
Indexed MeSH termsAmino Acid SequenceAmino AcidsAnimalsChemical FractionationChromatography, AffinityChromatography, High Pressure LiquidChromatography, Ion ExchangeInvertebrate HormonesLeechesMolecular Sequence DataSequence AlignmentSerine Proteinase Inhibitors

Summary

Antistasin, a potent inhibitor of the blood coagulation factor Xa, is the prototype of a novel family of serine-proteinase inhibitors.

Why This Matters for Hirudotherapy

This study describes the isolation, purification, sequencing, and biochemical characterization of hirustasin, a 55-amino-acid antistasin-type serine-proteinase inhibitor from Hirudo medicinalis. Hirustasin is notable as the only known single-domain antistasin-type protein and is the first leech-derived inhibitor of tissue kallikrein identified; it also tightly inhibits trypsin, chymotrypsin, and neutrophil cathepsin G, but despite high sequence similarity to antistasin—including near-conserved cysteine spacing—it does not inhibit factor Xa or blood coagulation in vitro. This work is relevant to ASH's domain as it expands the catalog of bioactive serine-proteinase inhibitors in the medicinal leech secretome and illustrates how structural similarity does not necessarily predict functional specificity. The honest caveat is that this is a biochemical characterization study with no in vivo, animal, or clinical data, and the abstract makes no therapeutic or efficacy claims.

Citation

Isolation and characterization of hirustasin, an antistasin-type serine-proteinase inhibitor from the medical leech Hirudo medicinalis.

Söllner C et al. · Eur J Biochem, 1994

DOI

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