Thrombolytic protein from cobra venom with anti-adhesive properties.

A metalloproteinase anticoagulant toxin of molecular weight 66 kDa has been purified from the venom of Indian monocled cobra (Naja kaouthia). This toxin named as NKV 66 cleaved fibrinogen in a dose and time dependent manner. The digestion process was specific to Aα chain and cleaved fibrinogen to peptide fragments. NKV 66 completely liquefied the fibrin clots developed in vitro in 18 h. Plasma recalcification time and thrombin time were significantly prolonged following treatment of plasma with NKV 66. NKV 66 significantly inhibited ADP and collagen induced platelet aggregation in a dose dependent manner. It showed disintegrin like activity on A549 cells cultured in vitro. About 40% inhibition of adherence of A549 cells to matrix was observed following NKV 66 treatment also NKV 66 treated A549 cells were drastically inhibited from passing through the matrix in cell invasion assays in vitro, suggesting anti-adhesive properties of NKV 66.