Cytotoxins (CTXs)

About Cytotoxins:

• The Cytotoxins (CTXs) are an essential class of the non-enzymatic three-finger toxin family and are ubiquitously present in cobra venoms. 
• These low-molecular-mass toxins, contributing to about 40 to 60% of the cobra venom proteome, play a significant role in cobra venom-induced toxicity, more prominently in dermonecrosis (local effects). 
• Some CTXs are also responsible for depolarizing neurons and heart muscle membranes, thereby contributing to cardiac failures frequently observed in cobra-envenomed victims. Consequently, they are also known as cardiotoxins (CdTx).
• Interestingly, the proportion of cobra venom CTXs varies dramatically across different cobra species. 
• Usually, venoms from African spitting cobras have a higher proportion of CTXs than the Asiatic cobra ones, indicating geographical variation in snake venom composition.

Key facts about the Cobra

• Cobras (genus Naja) are widely distributed over Asia and Africa.
• Cobra bites are responsible for large mortality and morbidity on these continents, including the Indian sub-continent. 
• Cobra venoms are neurotoxic. However, they also exhibit local cytotoxic effects at the envenomed site, and the extent of cytotoxicity may vary from species to species.

Q1) What are Three-finger toxins?

Three-finger toxins (TFTs) are the main venom components of snakes from Elapidae family. Amino acid sequences of more than five hundreds TFTs are determined; these toxins form one of the largest protein families present in snake venoms.

Source: Current insight on the mechanisms of Cobra venom cytotoxins can help anti-venom therapy