Related Experiment Video
Updated: Oct 19, 2025
Measurement of Factor V Activity in Human Plasma Using a Microplate Coagulation Assay
Published on: September 9, 2012
Identification of the factor XII contact activation site enables sensitive coagulation diagnostics
Marco Heestermans1, Clément Naudin1,2,3, Reiner K Mailer1
1Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
Researchers identified a key region in factor XII (FXII) essential for blood coagulation. This discovery offers new ways to diagnose clotting disorders and standardize tests like the activated partial thromboplastin time (aPTT).
Area of Science:
- Biochemistry
- Hematology
- Molecular Biology
Background:
- Contact activation, initiated by surface-induced factor XII (FXII) activation, is crucial for blood coagulation and measured by the activated partial thromboplastin time (aPTT) assay.
- Understanding the precise mechanisms and diagnostic relevance of FXII contact activation is vital for advancing hemostasis research and clinical practice.
Purpose of the Study:
- To elucidate the mechanism of FXII contact activation and explore its diagnostic implications.
- To identify specific regions of FXII involved in surface binding, activation, and subsequent thrombus formation.
- To investigate the potential of antibody-mediated FXII activation for diagnostic applications.
Main Methods:
- Screening of recombinant FXII mutants to pinpoint critical residues for activation.
- Utilizing peptides spanning identified regions to inhibit FXII activation.
- Employing mouse models to assess the in vivo role of FXII in thrombus formation.
- Generating antibodies against specific FXII regions to induce and control contact activation.
Main Results:
- A continuous stretch of residues, Gln317-Ser339, was identified as essential for FXII surface binding, activation, and thrombin generation.
- FXII mutants lacking this region were unable to support thrombus formation in mice, despite being activatable by plasmin and plasma kallikrein.
- Antibodies targeting the Gln317-Ser339 region induced FXII activation in solution, leading to controllable thrombin generation via the intrinsic coagulation pathway.
Conclusions:
- The Gln317-Ser339 region is a critical determinant of FXII's role in initiating blood coagulation through contact activation.
- Antibody-activated FXII offers a novel method for standardizing aPTT reagents and sensitive monitoring of key coagulation factors.
- This research provides mechanistic insights into FXII activation with significant implications for diagnosing and managing hemostatic disorders.
More Related Videos
03:53Author Spotlight: High-Sensitivity Tissue Factor Activity Assay for Plasma Diagnosis
Published on: December 29, 2023
09:38A Microfluidic Flow Chamber Model for Platelet Transfusion and Hemostasis Measures Platelet Deposition and Fibrin Formation in Real-time
Published on: February 14, 2017
Related Concept Videos
01:20Extrinsic 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...
01:09Coagulation
During the coagulation phase, clotting factors, or procoagulants, play a vital role in initiating and progressing the coagulation cascade. This cascade is a series of reactions...
01:30Anticoagulant Drugs: Low-Molecular-Weight Heparins