title: Platelet aggregation inhibitors from Agkistrodon acutus snake venom.
abstract: Among all the purified components from A. acutus venom, including ADPase, 5'-nucleotidase, phospholipase A2 and fibrinogenases, only the venom ADPase (50-100 micrograms/ml) shows marked inhibitory action on ADP (10 microM)-, collagen (10 micrograms/ml)- and sodium arachidonate (100 microM)-induced platelet aggregations of rabbit platelet-rich plasma. The venom 5'-nucleotidase (100 micrograms/ml) inhibited ADP-induced platelet aggregation by 31 +/- 4% (n = 4, P less than 0.05). Fibrinogenolytic enzymes (fractions I and IX, 100 micrograms/ml) did not significantly inhibit platelet aggregation induced by ADP (10 microM), collagen (10 micrograms/ml) or sodium arachidonate (100 microM). However, when the fibrinogenase (fraction IX, 100 micrograms/ml) was preincubated with platelet-rich plasma for 30 min it inhibited collagen (20 micrograms/ml)- and ADP (10 microM)-induced platelet aggregations by 34 +/- 9% (n = 4, P less than 0.05) and 35 +/- 6% (n = 4, P less than 0.05), respectively. The phospholipase A2 (100 micrograms/ml) did not affect platelet aggregation. The venom ADPase is a single chain polypeptide with a molecular weight of 94,000. The specific ADPase activity is estimated to be 4.3 mu moles Pi/min/mg of protein. It also possesses phosphodiesterase and weak 5'-nucleotidase activities.
mesh_terms: D015720:5'-Nucleotidase; D000818:Animals; D001081:Apyrase / Q000494:pharmacology; D005591:Chemical Fractionation; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002848:Chromatography, DEAE-Cellulose; D003435:Crotalid Venoms / Q000032:analysis*; D004591:Electrophoresis, Polyacrylamide Gel; D006867:Hydrolases / Q000302:isolation & purification / Q000494:pharmacology*; D066298:In Vitro Techniques; D008970:Molecular Weight; D009708:Nucleotidases / Q000494:pharmacology; D010974:Platelet Aggregation / Q000187:drug effects*; D011817:Rabbits; D013917:Thrombin / Q000494:pharmacology
chemical_list: C031442:Agkistrodon venoms; D003435:Crotalid Venoms; D006867:Hydrolases; D009708:Nucleotidases; D015720:5'-Nucleotidase; D013917:Thrombin; D001081:Apyrase