Tridegin, a new peptidic inhibitor of factor XIIIa, from the blood-sucking leech Haementeria ghilianii
Research article published in The Biochemical journal (1997)
Abstract
1. Crude salivary gland extract of the giant Amazon leech, Haementeria ghilianii, contains an inhibitor of plasma factor XIIIa. 2. The inhibitory agent was purified to homogeneity by anion-exchange, cation-exchange, gel-filtration and reverse-phase chromatography to yield a single band on SDS/PAGE with an apparent molecular mass of 7.3 kDa. It has been named tridegin. 3. Micro-sequencing of proteolytic fragments showed tridegin to be a peptide of 66 amino acids. The sequence is unique with little similarity to other leech-derived proteins. 4. Inhibition of plasma factor XIIIa activity was confirmed by four independent methods: tridegin increased the solubility of fibrin clots in urea, inhibited ammonia produced from the incorporation of ethylamine into casein, inhibited the incorporation of 5'-(biotinamido)pentylamine into casein and prevented gamma-dimer formation in clotting fibrinogen. 5. The IC50 of tridegin (approx. 9.2 nM) is very close to the concentration of factor XIIIa used in the assay and in fact depends on its concentration. This is the most potent inhibitor of factor XIIIa yet described. 6. Tridegin also inhibits platelet factor XIIIa (factor XIIIAa) with a similar potency to that of the plasma enzyme. 7. Tridegin also inhibits tissue transglutaminase but with lower potency and independently of the enzyme concentration. 8. Tridegin appears to be specific for transglutaminases, since it has no effect on the coagulation times of human plasma, on thrombin or factor Xa. Moreover it has no effect on other thiol-containing enzymes and has no ability to digest fibrinogen or cleave the isopeptide substrate, L-gamma-glutamyl-4-nitroanilide.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Resumen
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Por qué esto importa para la hirudoterapia
Este estudio aisló y caracterizó la tridegina, un nuevo inhibidor peptídico del factor XIIIa de 66 aminoácidos, proveniente de la sanguijuela gigante del Amazonas Haementeria ghilianii, purificado a partir de extracto crudo de glándula salival mediante múltiples pasos cromatográficos para obtener una proteína homogénea de 7.3 kDa con una secuencia única que muestra poca similitud con otras proteínas derivadas de sanguijuela. La tridegina inhibió el factor XIIIa plasmático y plaquetario con una IC50 de aproximadamente 9.2 nM —el inhibidor del factor XIIIa más potente descrito— y fue confirmada por cuatro métodos independientes, incluyendo el aumento de la solubilidad del coágulo de fibrina en urea y la prevención de la formación de gamma-dímeros. Esto es directamente relevante para el dominio de ASH, ya que identifica una nueva molécula bioactiva de la saliva de la sanguijuela con un mecanismo único dirigido al entrecruzamiento de la fibrina, distinto de las actividades anticoagulantes y antiplaquetarias de otras proteínas de sanguijuela. Sin embargo, el estudio es enteramente in vitro y no aporta datos animales ni clínicos.
Citación
Tridegin, a new peptidic inhibitor of factor XIIIa, from the blood-sucking leech Haementeria ghilianii
Finney S et al. · The Biochemical journal, 1997
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Añadido a la biblioteca ASH: May 27, 2026 · Última actualización del sitio: 18 de junio de 2026