Anticoagulant protein which binds to the gamma-carboxyglutamic acid-domain regions of factors IX (F9) and factor X (F10) in the presence of calcium with a 1 to 1 stoichiometry. Heterodimer of subunits A and B; disulfide-linked. Expressed by the venom gland. This protein seems to be found in newborn B.jararaca venom but not in adult snake venom. Glycosylated. Calcium is required for ligand binding. Belongs to the snaclec family.