Catalog #: DPGR008A
For research use only. Not for use in diagnostic procedures.
Two-site ELISA method for the measurement of TAFI antigen (Thrombin Activatable Fibrinolysis Inhibitor), on plasma or any biological sample where TAFI antigen must be measured. This assay is designed with a murine monoclonal antibody specific for TAFI, for coating the microplate (immunocapture) and a goat polyclonal antibody labeled with horseradish peroxidase (HRP) for revelation. Assay calibrator has a defined concentration of TAFI Ag, expressed as % of a normal pooled human plasma, and exactly determined with two duly selected human plasma pools. TAFI and TAFIa are identically measured.
Structure & Mechanism of Action
Thrombin Activatable Fibrinolysis Inhibitor (TAFI) is also called plasma procarboxypeptidase B or U. TAFI is synthesized in the liver and is released into the circulation by the liver as a proenzyme. It is a carboxypeptidase which can be activated to TAFIa by thrombin-thrombomodulin complex in an active enzyme, which inhibits fibrinolysis by cleaving lysine residues on the carboxy-terminal (COOH) ends of fibrin. This induces hypo-fibrinolysis by decreasing the fibrin capacity to bind tPA and plasminogen. TAFI has a molecular weight of 60 kD.
TAFI can be further cleaved by thrombin, trypsin, or plasmin. TAFIa down-regulates fibrinolysis by removing C-terminal lysines and arginines from fibrin that is already partially degraded by plasmin. Those lysine residues act as a ligand for the lysine-binding sites of plasminogen and tPA. TAFIa is a zinc and calcium dependant enzyme.
The TAFI antigen concentration in normal human plasma is usually between 40 and 250%. There are no variations with gender, or pregnancy. TAFI Ag concentration in normal human plasma is about 2.5 µg/ml.
Significance
High TAFI Ag concentrations involve a hypo-fibrinolytic status (reduction of fibrinolytic activity), which can induce an elevated risk of thrombosis. Measurement of TAFI Ag on plasma can indicate a risk of a hypo-fibrinolysis resulting from an excess of TAFI. The exact incidence of TAFI in thrombophilia, and association of elevated levels with risk of thrombosis, is currently under investigation.
Assay Principle
Human anticoagulated plasma is used. DiaPharma TAFI Ag is a sandwich ELISA specific for human TAFI. The diluted tested plasma is introduced into a microwell coated with a monoclonal antibody specific for human TAFI. When present, this protein is captured onto the solid phase. Following a washing step, the immunoconjugate, a goat polyclonal antibody coupled to HRP, is introduced and binds to the free epitopes of immobilized TAFI. Following a new washing step, the peroxidase substrate, TMB in presence of H2O2, is introduced and a colour develops. The amount of colour developed is directly proportional to the concentration of human TAFI in the tested sample.
Standard Curve
Assay Features
Minimum order of 20 kits required
| Name | Type | Size |
|---|---|---|
| DiaPharma Annexin V / FPA / TAFI Flyer | application/pdf | 56.01 kB |
| DiaPharma Brand Fibrinolysis Flyer | application/pdf | 376.24 kB |
| DiaPharma TAFI Flyer 1 | application/pdf | 319.72 kB |
| DiaPharma TAFI Flyer 2 | application/pdf | 265.17 kB |