Draculin

Draculin (named after Count Dracula) is a glycoprotein found in the saliva of vampire bats. It is composed of 708 amino acids, weighing about 76,9 kDa. 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. Draculin is a member of the lactotransferrin family of proteins that functions an antibacterial protein in other mammals, but has been co-opted in bat evolution to function as an anticoagulant.^[1]

Draculin is a reversible, slow tight binding, noncompetitive inhibitor of FXa. It does not act on thrombin, trypsin or chymotrypsin and does not express fibrinolytic activity. The protein increases the lag phase as well as the height of the peak of thrombin generation when in plasma, leading to prolonged bleeding.^[2]

Daily salivation of vampire bats yields a saliva that progressively decreases in anticoagulant activity. However, there is no significant change in overall protein content during this time. After a 4-day period of rest, anticoagulant activity of the saliva is restored. In addition, purified native draculin, obtained from high- and low-activity saliva, shows significant differences in composition of the carbohydrate moiety, and glycosylation pattern. Furthermore, controlled chemical deglycosylation of native draculin progressively leads to complete loss of the biological activity, despite the conditions leaving the polypeptide backbone intact.^{[citation needed]}

See also[]

• Desmoteplase

References[]

External links[]

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