FEATURES

FAMILY

DESCRIPTION

Also known as FAXC_PSETE, FAXC. Snake prothrombin activator that attacks the hemostatic system of prey. This non-catalytic subunit is functionally similar to blood coagulation factor V (PubMed:12362232, PubMed:23869089). It serves as a critical cofactor for the prothrombinase activity of the catalytic subunit, which is similar to the blood coagulation factor X (PubMed:12362232, PubMed:23869089). The complex converts prothrombin to thrombin by sequential cleavage at two positions, Arg-320 followed by Arg-271 (PubMed:23869089). Cleavage at Arg-320 produces an active intermediate known as meizothrombin (PubMed:23869089). Meizothrombin is the 'second' substrate for prothrombinase, and it docks in an altered manner to present the second cleavage site (271) (PubMed:23869089). Cleavage at Arg-271 releases active thrombin from its pro-fragment (PubMed:23869089). This order of events is reversed if the protease component of prothrombinase is used on its own, suggesting that the 271 site is inherently more accessible to proteolysis (PubMed:23869089). The complex converts prothrombin to thrombin in presence but also in the absence of membrane (PubMed:23869089). Heterodimer of a light and a heavy chains; disulfide-linked. Is associated with pseutarin-C non-catalytic subunit (AC Q7SZN0) in a non-covalent manner.

EXTERNAL LINKS

FAXC

Venom prothrombin activator pseutarin-C catalytic subunit

FAXC

Molecular Synopsis