Bothrops jararaca snake venom: effects on platelet aggregation.
Crude venom from Bothrops jararaca has procoagulant, platelet aggregating and phospholipase A2 (PLA2) activities. By chromatographic fractionation of the venom on Sephacryl S-200 it was possible to separate these three activities and to show that distinct protein components are involved. The procoagulant activity appears to involve the synergistic action of several components and was not further studied in the present work. The aggregating activity results from the action of two components: 1) a serino-proteinase PMSF-inhibitable similar to thrombocytin and 2) a PMSF-resistant, calcium- and plasma-dependent factor distinct from other previously described aggregating principles. Fractions possessing PLA2 activity were also able to inhibit platelet aggregation induced by collagen and accelerated the slow reversal of aggregation induced by ADP. Both PLA2 activity and inhibition of collagen-induced platelet aggregation displayed by these fractions were abolished by reaction with p-bromophenacyl bromide and 2-mercapto-ethanol. These results indicate that in B. jararaca venom the PLA2 activity and the factor inhibiting platelet aggregation may be related to the same protein molecule.