Cytotoxin (Snake venom cytotoxin) (CTX (commonly used for toxins within this family, especially from cobra venom))

Cytotoxins (sometimes called "venom cytotoxins," "three-finger cytotoxins," or "cobra venom CTXs") are a well-studied group of non-enzymatic, low-molecular-mass proteins found predominantly in the venom of cobras and some other elapid snakes. They are members of the three-finger toxin (3FTx) protein family and are structurally characterized by their three beta-sheet "fingers." Cytotoxins act primarily by disrupting cell membrane integrity, leading to cell death via necrosis or apoptosis. Some CTXs have additional effects—including depolarization of cardiac or neural cells—leading to the historical term "cardiotoxin" for certain subtypes. They are major mediators of tissue-damaging effects (dermonecrosis, ulceration) at envenomation sites and can contribute to systemic toxicity in severe cases. The primary means of neutralization is polyclonal antivenom; however, there is significant structural diversity among cytotoxins, complicating treatment and antivenom design. Accurate molecular and mechanistic classification of these toxins is preferred over older phenomenological terms based on the tissue affected.

Other names

Cobra venom cytotoxinCardiotoxin (CdTx, used in the past for certain CTXs with cardiac effects)CTXThree-finger cytotoxinNon-enzymatic three-finger toxinSometimes simply "cytotoxin" or "venom cytotoxin"

Drugs (antivenoms) neutralize cytotoxins by binding and facilitating their removal or blocking cellular access. Cytotoxins themselves act by inserting into and disrupting biological membranes, causing cell lysis, apoptosis, or necrosis.