Draculin

Draculin (named after Count Dracula) is a glycoprotein found in the saliva of vampire bats. It is composed of 411 amino acids, weighing about 88.5kDa. It functions as an anticoagulant, inhibiting coagulation factors IX (IXa) and X (Xa), thus keeping the blood of the bitten victim from clotting while the bat is drinking.