American Society of Hirudotherapy

New N alpha-guanidinobenzoyl derivatives of hirudin-54-65 containing stabilized carboxyl or phosphoryl groups on the side chain of phenylalanine-63

Research article published in Journal of medicinal chemistry (1994)

Last Updated: June 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Preclinical (animal)Drug DevelopmentThurieau C et al. · Journal of medicinal chemistry, 1994

Abstract

We report on the synthesis and pharmacological properties of a new series of thrombin inhibitors derived from hirudin carboxyl-terminal fragments. Two (arylphosphono)phenylalanines, p-PO3H2-L-Phe1 and m-PO3H2-L-Tyr, and one (carboxymethyl)phenylalanine, p-CH2COOH-L-Phe, were prepared and incorporated into position 63 of the modified hirudin's C-terminal dodecapeptide using the Fmoc solid-phase synthesis strategy. Substitution by any one of the residues led to very active analogs which doubled the thrombin time at low micromolar concentration (Ctt2) in vitro (1 microM < Ctt2 < 3 microM) and potently increased the activated partial thromboplastin time (APTT) ex vivo. These compounds displayed a higher potency in vitro and a longer duration of action in vivo than both the corresponding sulfated or phosphorylated tyrosine counterparts.

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 SequenceAnimalsDrug StabilityFibrinogenGuanidinesHirudinsHydrolysisKineticsMolecular Sequence DataPeptide FragmentsPhenylalanineRatsStructure-Activity RelationshipThrombin

Summary

Guanidinobenzoyl derivatives of the hirudin 54-65 dodecapeptide bearing phosphono- or carboxymethyl-phenylalanine at position 63 doubled thrombin time at 1-3 microM in vitro, prolonged APTT ex vivo and outlasted sulfated or phosphorylated tyrosine analogues in vivo.

Why This Matters for Hirudotherapy

This study reports the synthesis and pharmacological properties of a new series of thrombin inhibitors derived from hirudin carboxyl-terminal fragments, incorporating one of three residues—p-PO3H2-L-Phe, m-PO3H2-L-Tyr, or p-CH2COOH-L-Phe—at position 63 of the modified hirudin C-terminal dodecapeptide via Fmoc solid-phase synthesis. The resulting analogs doubled thrombin time at low micromolar concentrations (1 µM < Ctt2 < 3 µM) in vitro, potently increased activated partial thromboplastin time ex vivo, and displayed higher in-vitro potency and longer in-vivo duration than the corresponding sulfated or phosphorylated tyrosine counterparts. These are hirudin-derived analogs, but the abstract evaluates chemically synthesized fragments rather than natural leech secretions or live hirudotherapy.

Citation

Reference (Vancouver style)

Thurieau C, Simonet S, Paladino J, Prost JF, Verbeuren T, Fauchère JL. New N alpha-guanidinobenzoyl derivatives of hirudin-54-65 containing stabilized carboxyl or phosphoryl groups on the side chain of phenylalanine-63. J Med Chem. 1994;37(5):625-629. doi:10.1021/jm00031a012. PMID: 8126702

Bibliographic details (authors, volume, pages, DOI) are taken from the PubMed record.

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

This website provides educational information and does not constitute medical advice, diagnosis, or treatment recommendations. Medicinal leech therapy carries clinically meaningful risks and should be performed only by qualified clinicians under institutionally approved protocols. FDA 510(k) clearance for medicinal leeches is limited to specific indications; investigational and off-label discussions are labeled accordingly. For patient-specific guidance, consult a qualified healthcare provider.