Purification and partial characterization of an anticoagulant PLA2 from the venom of Indian Daboia russelii that induces inflammation through upregulation of proinflammatory mediators

The present study describes the purification and partial characterization of a basic anticoagulant PLA2 enzyme named as Rv(i) PLA2 from the venom of Indian Daboia russelii. The molecular mass of the protein was found to be 13,659.65 Da, and peptide mass fingerprinting revealed that it belongs to group II PLA2 family. The peptide sequence showed similarity to uncharacterized basic PLA2 enzyme having an accession no. of P86368 reported from Sri Lankan D. russelii. Rv(i) PLA2 exhibited strong phospholipase A2 and anticoagulant activity. It also induced expression of COX-2 and TNF-α mRNA in a dose-dependent manner in phorbol 12-myristate 13-acetate differentiated THP-1 cells, which play a crucial role during inflammation. Chemical modification of His residue in Rv(i) PLA2 with p-bromophenacyl bromide abolished the enzymatic, anticoagulant, and inflammatory activities. The result indicates that the catalytic site of Rv(i) PLA2 might play a vital role in inducing inflammation at the bite site during D. russelii envenomation.