Reactome: A Curated Pathway Database

Activated protein C cleaves factor Va to factor Vi intermediate form

Stable Identifier
Homo sapiens
factor Va -> factor Vi
Locations in the PathwayBrowser

Activated protein C cleaves peptide bonds in activated factor V (factor Va), converting it to an inactive form (factor Vi). APC proteolysis involves cleavage of the factor Va heavy chain at Arg-334 (306 if signal peptide is not included) and Arg-534 (506 with no signal peptide) (Nicolaes et al. 1985). Most factor Va molecules are initially cleaved at Arg-534, yielding a partially active intermediate, followed by complete inactivation through cleavage at Arg-334 (Kalafatis et al. 1994). Factor Xa inhibits Arg-534 cleavage but this effect is mitigated by Protein S (Norstrom et al. 2006). A mutation of the APC cleavage sites in Fv at Arg-534Gln a.k.a. FVLeiden is the most common identifiable hereditary risk factor for venous thrombosis among Caucasians (Camire 2011).

Literature References
PubMed ID Title Journal Year
Participant Of
This entity is regulated by:
Title Physical Entity Activity
serine-type endopeptidase activity of Activated protein C:Protein S [plasma membrane] Activated protein C:Protein S [plasma membrane] serine-type endopeptidase activity (0004252)
Orthologous Events