Isolation and characterization of two new Lys49 PLA2s with heparin neutralizing properties from Bothrops moojeni snake venom

Among the proteins and peptides already characterized in Bothrops moojeni venom, two novel phospholipases A₂ (PLA₂) have been purified and fully sequenced by ESI-MS/MS techniques. Both of them belong to the enzymatically non-active Lys49 variants of PLA₂. They consist of 122 amino acids and share a characteristic sequence in their C-terminal region composed of clusters of basic amino acids known to interact with heparin. Thus, as already established, heparin can be used as an antidote to antagonize some myotoxic PLA₂s from venoms of Bothrops genus. The two PLA₂ variants were shown to interact in vitro with unfractionated heparin (UFH) and low molecular weight heparin (LMWH), neutralizing their anticoagulant properties. Although the influences of PLA₂s from snake venoms on the blood coagulation system are known, their use to antagonize the anticoagulant effect of heparin in vitro or in vivo has never been proposed. These finding recommend diagnostic and therapeutic applications, which are currently investigated.