Related Experiment Video
Updated: Jun 4, 2026

Rapid Point-of-Care Assay of Enoxaparin Anticoagulant Efficacy in Whole Blood
Published on: October 12, 2012
Protamine sulfate stimulates degradation of factor Xa and the factor Xa-antithrombin complex
Martin H Coggin1, Rebecca Ahl, Amie Roland
1Departments of Biological Sciences and Chemistry, Bowling Green State University, Bowling Green, OH 43403, USA.
Abstract:
The effect of protamine sulfate on factor Xa (FXa) and the factor Xa-antithrombin complex was studied via SDS-PAGE and Western blot analysis. Human factor Xa [(FXaα) ∼52 kDa, FXaβ ∼47 kDa] and human antithrombin (AT ∼55 kDa) form a primary (1°) complex at 109 and 104 kDa, a secondary (2°) complex at 99 and 95 kDa, and a tertiary (3°) complex at 66 and 62 kDa, as detected with polyclonal anti-FXa and anti-AT antibodies. Addition of protamine sulfate stimulates a transformation from free FXaα to FXaβ and degradation thence to inactive FXaγ (∼30 kDa), as well as transformation of FXaα-AT complexes to FXaβ-AT complexes. Additionally, protamine sulfate promotes digestive degradation from 1° to 3° complexes and FXaγ by the active enzyme. It further promotes reduction in total complex formation as a function of stimulation of hydrolysis of FXa moieties from the complex, thereby generating ATM. Protamine sulfate effects are proportional to the protamine sulfate concentration.
More Related Videos
Related Concept Videos
Anticoagulant Drugs: Low-Molecular-Weight Heparins
Venous Thrombosis III: Interprofessional Care
Anticoagulant Drugs: Vitamin K Antagonists and Direct Oral Anticoagulants
Warfarin, a prominent vitamin K antagonist family member, exerts its effect by inhibiting the enzyme VKORC1 (vitamin K epoxide reductase complex 1). By hindering this enzyme, warfarin...
Clot Retraction and Fibrinolysis
Extrinsic and Intrinsic Pathways of Hemostasis
The Extrinsic Pathway
The extrinsic pathway of coagulation is typically initiated by tissue damage that exposes blood to tissue factor (TF), a protein released by the damaged tissue cells outside the blood vessels—this interaction with TF triggers biochemical reactions involving specific clotting factors. The key player here is Factor VII, which forms a...
Depolarizing Blockers: Pharmocokinetics

