Fibrinogenolytic toxin from Indian monocled cobra (Naja kaouthia) venom
C Chandra Sekhar1, Dibakar Chakrabarty
1Department of Biological Sciences, Birla Institute of Technology and Science-Pilani, KK Birla Goa Campus, Zuarinagar, Goa 403726, India.
Abstract:
A fibrinogenolytic toxin of molecular weight 6.5 kDa has been purified from the venom of Indian monocled cobra (Naja kaouthia) by repeated cation exchange chromatography on CM-sephadex C-50. The purified toxin did not show any phospholipase activity but was mildly hemolytic on human erythrocytes. This toxin, called Lahirin, cleaved fibrinogen in a dose- and time-dependent manner. The digestion process apparently started with the A alpha chain, and gradually other lower-molecular-weight chains were also cleaved to low-molecular-weight peptides. The fibrinolytic activity was completely lost after treatment with ethylene di-amine tetra acetic acid (EDTA). However, exposure to 100 degree C for 1 min or pre-treatment with phenyl methyl sulfonyl fluoride (PMSF) did not affect the fibrinolytic activity. Cleavage of di-sulphide bonds by beta-mercaptoethanol or unfolding the protein with 4 M urea caused complete loss of activity of pure Lahirin.
Related Concept Videos
Clot Retraction and Fibrinolysis
Bacterial Toxins
Botulism
Diphtheria
Extrinsic and Intrinsic Pathways of Hemostasis
The Extrinsic Pathway
The extrinsic pathway of coagulation is typically initiated by tissue damage that exposes blood to tissue factor (TF), a protein released by the damaged tissue cells outside the blood vessels—this interaction with TF triggers biochemical reactions involving specific clotting factors. The key player here is Factor VII, which forms a...
Types of Toxins
Air pollutants, primarily gases, pose significant threats to respiratory health, leading to conditions like hypoxia, lung cancer, and in extreme cases, death.
Environmental pollutants like...


