American Society of Hirudotherapy

Biochemical characterization of a thrombin inhibitor from the bloodsucking bug Dipetalogaster maximus

Comparative study published in Haemostasis (1999)

Last Updated: June 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Observational studySalivary PharmacologyDrug DevelopmentLange U et al. · Haemostasis, 1999

Abstract

From the bloodsucking bug Dipetalogaster maximus, a protein with anticoagulant activity was isolated and biochemically characterized. The isolated protein, named dipetalogastin, possesses an average molecular mass of 11.8 kD. Its N-terminal sequence shows homology to rhodniin, a thrombin inhibitor isolated from the bug Rhodnius prolixus. The in vitro anticoagulant activity of dipetalogastin occurs via the inhibition of thrombin. The anticoagulant and thrombin inhibitory potency of dipetalogastin is comparable to that of recombinant hirudin. Its specific thrombin inhibitory activity is 9,300 antithrombin units/mg protein. Dipetalogastin forms only 1:1 molar complexes with thrombin. It is a tight-binding inhibitor of thrombin possessing a dissociation constant of 125 fM. It does not inhibit factor Xa or alpha-chymotrypsin and only weakly inhibits trypsin.

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

Publication typeComparative StudyJournal Article
Indexed MeSH termsAmino Acid SequenceAnimalsAnticoagulantsBlood Coagulation TestsChromatography, AffinityChromatography, GelChromatography, High Pressure LiquidEndopeptidasesEnzyme InhibitorsFactor XFibrinogenHirudins

Summary

Dipetalogastin, a thrombin inhibitor from Dipetalogaster maximus, is a tight-binding inhibitor with dissociation constant of 125 fM and specific thrombin inhibitory activity comparable to recombinant hirudin.

Why This Matters for Hirudotherapy

This study describes the isolation and biochemical characterization of dipetalogastin, an 11.8 kDa thrombin inhibitor from the bloodsucking bug Dipetalogaster maximus. Dipetalogastin forms a 1:1 complex with thrombin, exhibits a dissociation constant of 125 fM, and has specific thrombin inhibitory activity of 9,300 antithrombin units/mg, which the authors describe as comparable to recombinant hirudin. Its N-terminal sequence shows homology to rhodniin, another insect-derived thrombin inhibitor. The relevance to ASH's domain is indirect: although dipetalogastin is biochemically analogous to leech-derived hirudin as a potent, tight-binding thrombin inhibitor from a blood-feeding invertebrate, it originates from a heteropteran insect, not a leech. No leeches or leech-derived molecules were studied; the hirudin comparison serves solely as a benchmark for inhibitor potency.

Citation

Biochemical characterization of a thrombin inhibitor from the bloodsucking bug Dipetalogaster maximus.

Lange U et al. · Haemostasis, 1999

DOI

Added to ASH library: May 27, 2026 · Site last updated: June 18, 2026

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