The amino acid sequence of antistasin. A potent inhibitor of factor Xa reveals a repeated internal structure
Research article published in Journal of biological chemistry (1988)
Abstract
Antistasin is a 15-kDa protein from the salivary glands of the Mexican leech, Haementeria officinalis, which manifests anticoagulant activity by inhibiting factor Xa. Previous work demonstrating the presence of this activity in salivary gland extracts and its partial purification has been reported (Tuszynski, G. P., Gasic, T. B, and Gasic, G.J. (1987) J. Biol. Chem. 262, 9718-9723). The present study includes further purification to homogeneity of antistasin and its subsequent fragmentation and complete amino acid sequence determination. The protein, which possesses 119 amino acid residues, is blocked at its amino terminus by the presence of a pyroglutamic acid residue and has an unusually high cysteine content, with 20 cysteine residues. The primary structure of antistasin shows no homology to hirudin, a 65-residue anticoagulant protein from the medicinal leech, Hirudo medicinalis. Of great interest is the finding of significant internal homology within antistasin where a 2-fold internal repeated structure is observed. At least four isoforms of antistasin have been identified in leech salivary gland extracts by high performance liquid chromatography analysis, and partial amino acid sequence analysis of these isoforms indicates they differ by 1 or 2 amino acid residues.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Resumen
The amino acid sequence of antistasin. A potent inhibitor of factor Xa reveals a repeated internal structure.
Por qué esto importa para la hirudoterapia
This study reports the further purification and complete amino acid sequence determination of antistasin, a 15-kDa factor Xa inhibitor from the salivary glands of the Mexican leech Haementeria officinalis. Antistasin comprises 119 residues, has an amino-terminal pyroglutamic acid block, a high cysteine content (20 residues), a 2-fold internal repeated structure, no homology to hirudin (the 65-residue anticoagulant from Hirudo medicinalis), and at least four isoforms differing by 1-2 residues. For ASH's domain, this is directly relevant as foundational molecular characterization of a leech salivary anticoagulant. CAVEAT: This is structural/biochemical work with no in-vivo or clinical data; it concerns a specific Haementeria protein distinct from hirudin, so relevance to hirudotherapy using medicinal leeches is indirect.
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Añadido a la biblioteca ASH: May 27, 2026 · Última actualización del sitio: June 18, 2026