[Inactivation of factor X by plasmin]

Area of Science:

• Biochemistry
• Hematology
• Enzymology

Context:

• Investigating the interaction between plasmin and coagulation factor X.
• Examining the role of plasmin in the coagulation cascade.
• Understanding thrombin generation mechanisms.

Purpose:

• To determine if plasmin activates factor X.
• To elucidate the effect of plasmin on factor X activity.
• To assess the impact of plasmin proteolysis on prothrombin preparations.

Summary:

• Plasmin does not activate factor X to factor Xa; instead, it inactivates factor X.
• Incubation with plasmin renders factor X incapable of conversion to factor Xa in sodium citrate.
• Prothrombin preparations treated with plasmin lose thrombin generation capacity, which is partially restored by adding factor X.

Impact:

• Reveals a previously unrecognized inhibitory role of plasmin on factor X.
• Clarifies a mechanism by which plasmin can modulate coagulation.
• Provides insights into the complex regulation of thrombin formation.