Purification of anticoagulant factor from the spine venom of the crown-of-thorns starfish, Acanthaster planci.

The fraction with anticoagulant activity was purified from the spine venom of Acanthaster planci by fractionation with ammonium sulfate followed by column chromatography and designated plancinin. Its molecular weight determined by tricine-SDS polyacrylamide gel electrophoresis was about 7500 in native form and about 3000 in reduced conditions. Plancinin showed neither platelet aggregation nor an enhancement of vascular permeability. Fibrin formation time was prolonged by 25 micrograms of plancinin which was comparable to 0.08 units of heparin. 2-Mercaptoethanol inhibited the anticoagulant activity of plancinin with a 50% inhibition concentration of 5.6 x 10(-3) M. The bleeding time of mice was significantly prolonged by i.v. administration of plancinin and this effect was lost when plancinin was given orally or s.c. These data indicate that plancinin is a peptide with disulfide bond which is essential for the anticoagulant activity.