Американское общество гирудотерапии

A new factor Xa inhibitor (lefaxin) from the Haementeria depressa leech

Biochemistry study published in Thrombosis and Haemostasis (1999)

Последнее обновление: June 18, 2026Рецензент: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Observational studyГеномика и протеомикаФармакология секрета слюнных желёзFaria F et al. · Thrombosis and haemostasis, 1999

Abstract

The salivary complex of the leech Haementeria depressa produces potent anticoagulant components. Among them, a protein named lefaxin inhibits factor Xa (FXa). Lefaxin was purified to homogeneity from dissected salivary complexes by gel filtration in Sephadex G-150 followed by two ion exchange chromatography steps in Mono-Q. Inhibition of FXa by lefaxin was demonstrated by the inhibition of its amidolytic activity, measured with chromogenic substrate S-2765 (apparent K(I) of 4 nM), and of its ability to inhibit thrombin generation in the prothrombinase complex (EC50 of 40 nM). Lefaxin has a molecular weight of 30 kDa and an isoelectric point of 5.7. It is made of a polypeptide chain whose N-terminal sequence shows no similarity with that of other FXa inhibitors (antistasin and ghilianten) isolated from leech saliva. On the other hand, the N-terminal sequence of lefaxin presents significant sequence similarity with nitric oxide carrier proteins myohemerythrin from the annelid Nereis diversicolor and prolixin S from the triatoma Rhodnius prolixus. Interestingly, prolixin S also proved to be an anticoagulant protein acting on FXa.

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 SequenceAnimalsAnticoagulantsBlood CoagulationChromatography, GelChromatography, Ion ExchangeChromogenic CompoundsFactor Xa InhibitorsHelminth ProteinsHemeproteinsHemerythrinHumans

Резюме

Isolates lefaxin, a 30-kDa Factor Xa inhibitor from Haementeria depressa — characterizes inhibition kinetics and anticoagulant activity.

Почему это важно для гирудотерапии

This study purified lefaxin, a factor Xa inhibitor, from the salivary complex of the leech Haementeria depressa, demonstrating inhibition of FXa amidolytic activity (apparent Ki ~4 nM) and of thrombin generation in the prothrombinase complex (EC50 ~40 nM). Lefaxin is a 30-kDa protein (pI 5.7) whose N-terminal sequence shows no similarity to other leech FXa inhibitors antistasin and ghilianten, but does share similarity with myohemerythrin from the annelid Nereis diversicolor and prolixin S from the triatoma Rhodnius prolixus, itself an FXa-targeting anticoagulant. This is relevant to ASH as it expands the known diversity of leech-secreted FXa inhibitors. However, the study is limited to in-vitro biochemical purification and characterization; no in-vivo or clinical data are reported.

Цитирование

A new factor Xa inhibitor (lefaxin) from the Haementeria depressa leech.

Faria F et al. · Thrombosis and haemostasis, 1999

DOIPubMed

Связанный клинический контекст

Узнайте, как это исследование связано с клинической практикой

Species IdentificationTaxonomySalivary Gland SecretionAnti-Inflammatory MechanismsSalivary ComplexAnticoagulation CompoundsHemostasisDirect Thrombin InhibitorsOtolaryngologyFactor Xa Inhibitors

Добавлено в библиотеку ASH: May 27, 2026 · Последнее обновление сайта: June 18, 2026

Этот сайт предоставляет образовательную информацию и не является медицинской консультацией, диагнозом или рекомендацией по лечению. Гирудотерапия сопряжена с клинически значимыми рисками и должна проводиться только квалифицированными клиницистами в рамках институционально утверждённых протоколов. Разрешение FDA 510(k) для медицинских пиявок ограничено определёнными показаниями; обсуждения исследовательского и нелицензионного применения отмечены соответствующим образом. Для индивидуальных медицинских рекомендаций обратитесь к квалифицированному медицинскому специалисту.