Enhancement of heparin cofactor II anticoagulant activity
Research article published in The Journal of biological chemistry (1999)
Abstract
Heparin cofactor II (HCII) is a serpin whose thrombin inhibition activity is accelerated by glycosaminoglycans. We describe the novel properties of a carboxyl-terminal histidine-tagged recombinant HCII (rHCII-CHis(6)). Thrombin inhibition by rHCII-CHis(6) was increased >2-fold at approximately 5 microgram/ml heparin compared with wild-type recombinant HCII (wt-rHCII) at 50-100 microgram/ml heparin. Enhanced activity of rHCII-CHis(6) was reversed by treatment with carboxypeptidase A. We assessed the role of the HCII acidic domain by constructing amino-terminal deletion mutants (Delta1-52, Delta1-68, and Delta1-75) in wt-rHCII and rHCII-CHis(6). Without glycosaminoglycan, unlike wt-rHCII deletion mutants, the rHCII-CHis(6) deletion mutants were less active compared with full-length rHCII-CHis(6). With glycosaminoglycans, Delta1-68 and Delta1-75 rHCIIs were all less active. We assessed the character of the tag by comparing rHCII-CHis(6), rHCII-CAla(6), and rHCII-CLys(6) to wt-rHCII. Only rHCII-CHis(6) had increased activity with heparin, whereas all three mutants have increased heparin binding. We generated a carboxyl-terminal histidine-tagged recombinant antithrombin III to study the tag on another serpin. Interestingly, this mutant antithrombin III had reduced heparin cofactor activity compared with wild-type protein. In a plasma-based assay, the glycosaminoglycan-dependent inhibition of thrombin by rHCII-CHis(6) was significantly greater compared with wt-rHCII. Thus, HCII variants with increased function, such as rHCII-CHis(6), may offer novel reagents for clinical application.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Resumen
Heparin cofactor II (HCII) is a serpin whose thrombin inhibition activity is accelerated by glycosaminoglycans.
Por qué esto importa para la hirudoterapia
Este estudio describe un cofactor II de heparina recombinante con etiqueta de histidina carboxilo-terminal (rHCII-CHis(6)) que muestra una inhibición de la trombina mejorada en más de 2 veces a concentraciones de heparina mucho más bajas en comparación con el HCII recombinante de tipo silvestre, con la mejora revertida por el tratamiento con carboxipeptidasa A. La mutagénesis por deleción y los ensayos basados en plasma confirmaron la actividad anticoagulante mejorada dependiente de glicosaminoglucanos. Si bien este trabajo se refiere a la inhibición de la trombina —un mecanismo central también dirigido por la hirudina derivada de sanguijuelas—, el estudio involucra una serpina humana diseñada mediante tecnología de ADN recombinante y no involucra sanguijuelas, extractos de sanguijuelas ni moléculas derivadas de sanguijuelas en ninguna capacidad. Por lo tanto, su relevancia para la hirudoterapia o el secretoma de la sanguijuela es solo indirecta, ya que ofrece antecedentes contextuales sobre estrategias anticoagulantes alternativas en lugar de informar directamente sobre terapéuticas basadas en sanguijuelas.
Citación
Enhancement of heparin cofactor II anticoagulant activity
Bauman SJ et al. · The Journal of biological chemistry, 1999
Contexto clínico relacionado
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Añadido a la biblioteca ASH: May 27, 2026 · Última actualización del sitio: 18 de junio de 2026