Procoagulant and platelet-aggregating properties of cerastocytin from Cerastes cerastes venom.
Cerastocytin is a thrombin-like serine protease with potent platelet-proaggregating properties. It is able to activate factor XIII but is less active than thrombin on plasma coagulation. The aggregation induced by cerastocytin resembles that induced by thrombin, since rabbit washed platelets desensitized by a pretreatment with thrombin do not aggregate in the presence of cerastocytin. Furthermore, preincubation of platelets with monoclonal antibodies specific for glycoproteins GPIb or GPIIbIIIa blocks receptor sites for thrombin and fibrinogen, respectively, and prevents their aggregation induced by thrombin or cerastocytin. A monoclonal antibody, inhibitor of von Willebrand factor (VWF)-dependent agglutination, blocks the aggregation induced by cerastocytin. After activation with cerastocytin, washed rabbit platelets degranulate and secrete ATP and phospholipase A2. However, cerastocytin is less potent in inducing the release of phospholipase A2 than in inducing ATP secretion.
Marrakchi
N
N
Laboratoire des Venins et Toxines, Institut Pasteur de Tunis, Belvédère, Tunisia.
Barbouche
R
R
Guermazi
S
S
Bon
C
C
el Ayeb
M
M
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001777:Blood Coagulation / Q000187:drug effects*; D001792:Blood Platelets / Q000187:drug effects; D005260:Female; D006801:Humans; D006868:Hydrolysis; D008297:Male; D010741:Phospholipases A / Q000378:metabolism; D054467:Phospholipases A2; D010974:Platelet Aggregation / Q000187:drug effects*; D011817:Rabbits; D013917:Thrombin / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000494:pharmacology*; D014757:Viper Venoms / Q000494:pharmacology*; D017819:Viperidae
D000911:Antibodies, Monoclonal; D014757:Viper Venoms; D000255:Adenosine Triphosphate; D010741:Phospholipases A; D054467:Phospholipases A2; C093951:cerastocytin; D013917:Thrombin