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Author Spotlight: High-Sensitivity Tissue Factor Activity Assay for Plasma Diagnosis
Published on: December 29, 2023
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Activity of Factor XII-Locarno
Bassem M Mohammed1,2, Ivan Ivanov1, Anton Matafonov1,3
1Department of Medicine, Vanderbilt University Medical Center, Nashville, TN.
Research and Practice in Thrombosis and Haemostasis
|January 23, 2018
Summary
The Pro353 substitution in single-chain Factor XII (sc-FXII) impacts its activity. FXII-R353A shows enhanced cofactor-dependent prekallikrein activation and promotes thrombin generation better than FXII-R353P.
Area of Science:
- Biochemistry
- Molecular Biology
- Hemostasis
Background:
- Factor XII (FXII) Locarno, a natural variant, has proline at Arg353, preventing activation to FXIIa.
- Single-chain FXII (sc-FXII) with Arg353 replaced by alanine exhibits cofactor-enhanced proteolytic activity.
Purpose of the Study:
- To investigate the effect of the Pro353 substitution on sc-FXII activity.
- To compare the functional consequences of FXII-R353P and FXII-R353A variants.
Main Methods:
- Assessed prekallikrein activation by wild-type FXII (FXII-WT), FXII-R353A, and FXII-R353P.
- Evaluated thrombin generation and coagulation in plasma in a factor XI-dependent manner.
Main Results:
- FXII-R353P and FXII-R353A resisted conversion to FXIIa.
- FXII-R353A demonstrated cofactor-enhanced prekallikrein activation, superior to FXII-R353P.
- FXII-R353A was a more potent promoter of factor XI-dependent thrombin generation and coagulation than FXII-R353P.
Conclusions:
- sc-FXII activity is sensitive to alterations in the activation loop at residue 353.
- The Pro353 substitution likely disrupts key interactions, affecting the active conformation of sc-FXII.
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