Podcast
Questions and Answers
TFPI:Xa binds to TF: FVIIa complex.
TFPI:Xa binds to TF: FVIIa complex.
False
Thrombomodulin-thrombin complex triggers the protein S system.
Thrombomodulin-thrombin complex triggers the protein S system.
False
Protein S lacks protease activity.
Protein S lacks protease activity.
True
APC dissociates from EPCR and interacts with PC in a 2:1 stoichiometric complex.
APC dissociates from EPCR and interacts with PC in a 2:1 stoichiometric complex.
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TF pathway is shut off as soon as a small amount of FXa is generated.
TF pathway is shut off as soon as a small amount of FXa is generated.
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Protein S forms two main types: Free PS and Protein C-bound PS.
Protein S forms two main types: Free PS and Protein C-bound PS.
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Tissue Factor Pathway Inhibitor (TFPI) is the principal regulator of the protein C regulatory system.
Tissue Factor Pathway Inhibitor (TFPI) is the principal regulator of the protein C regulatory system.
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Antithrombin does not require protein Z, phospholipid & Ca++ to inhibit FXIa.
Antithrombin does not require protein Z, phospholipid & Ca++ to inhibit FXIa.
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Antithrombin (AT) is synthesized in the liver and activated by the presence of excess thrombin.
Antithrombin (AT) is synthesized in the liver and activated by the presence of excess thrombin.
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The protein C regulatory system ensures that coagulation is widespread throughout the body.
The protein C regulatory system ensures that coagulation is widespread throughout the body.
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Protein Z is synthesized in the liver and is a proteolytic enzyme.
Protein Z is synthesized in the liver and is a proteolytic enzyme.
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Thrombin-thrombomodulin complex revises the function of thrombin from an anticoagulant to a procoagulant.
Thrombin-thrombomodulin complex revises the function of thrombin from an anticoagulant to a procoagulant.
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Heparin cofactor II (HCII) targets thrombin and does not require heparin.
Heparin cofactor II (HCII) targets thrombin and does not require heparin.
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Tissue Factor Pathway Inhibitor (TFPI) induces a conformational change of Antithrombin (AT) to allow binding of activated coagulation factors.
Tissue Factor Pathway Inhibitor (TFPI) induces a conformational change of Antithrombin (AT) to allow binding of activated coagulation factors.
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TFPI binds to heparan sulfate and releases TFPI by 7x Domain.
TFPI binds to heparan sulfate and releases TFPI by 7x Domain.
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The reaction activity of Antithrombin is independent of the length of the heparin chain it binds to.
The reaction activity of Antithrombin is independent of the length of the heparin chain it binds to.
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Kunitz-type serine protease inhibitor is a component of the Tissue Factor Pathway Inhibitor (TFPI).
Kunitz-type serine protease inhibitor is a component of the Tissue Factor Pathway Inhibitor (TFPI).
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Protein C Inhibitor targets thrombin as one of the serine proteases it inhibits.
Protein C Inhibitor targets thrombin as one of the serine proteases it inhibits.
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Study Notes
Coagulation Factors and Inhibitors
- TFPI (Tissue Factor Pathway Inhibitor) binds to the TF (Tissue Factor):FVIIa complex, functioning as a primary regulator of the protein C system.
- The presence of thrombin in the thrombin-thrombomodulin complex activates the protein C system, promoting anticoagulant effects.
- Protein S exists in two forms: Free Protein S (PS) and Protein C-bound PS, with Protein S lacking direct protease activity.
- APC (Activated Protein C) dissociates from EPCR (Endothelial Protein C Receptor) to form a 2:1 complex with Protein C, indicating its regulatory role in coagulation.
- A minimal generation of FXa (Factor Xa) leads to the immediate inhibition of the tissue factor pathway, preventing coagulation.
Antithrombin and Other Inhibitory Proteins
- Antithrombin (AT) does not need protein Z, phospholipids, or calcium to inhibit FXIa, showcasing its broad inhibitory capacity.
- Synthesized in the liver, AT's activity is enhanced by the presence of excess thrombin.
- Heparin cofactor II (HCII) specifically targets thrombin, functionally independent from heparin.
- TFPI induces a conformational alteration in Antithrombin, facilitating its interaction with activated coagulation factors.
- The reaction efficacy of Antithrombin remains constant irrespective of heparin chain length, revealing its innate functional properties.
Protein Z and Related Functions
- Protein Z, also synthesized in the liver, acts as a proteolytic enzyme, playing a support role in coagulation regulation.
- The thrombin-thrombomodulin complex shifts thrombin's function from anticoagulant to procoagulant, influencing the coagulation balance in the body.
- Kunitz-type serine protease inhibitors are integral components of TFPI, highlighting the complexity of the coagulation regulatory system.
Systemic Regulation of Coagulation
- The protein C regulatory system serves to balance coagulation across the body, minimizing the risk of widespread thrombosis.
- This regulation is crucial for maintaining hemostatic equilibrium, ensuring coagulation occurs only when necessary and is appropriately controlled.
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Description
Explore the regulatory mechanisms of the protein C system in blood coagulation. Learn about inhibitors and co-factors that maintain a balance between thrombosis and abnormal bleeding, slow down procoagulant activation, suppress thrombin production, and prevent excessive clotting.
