Venom contains more than 20 different compounds, which are mostly proteins and polypeptides.[
Snake venom is a highly toxic saliva[1] containing zootoxins that facilitates in the immobilization and digestion of prey. This also provides defense against threats. Snake venom is injected by unique fangs during a bite, whereas some species are also able to spit venom.[2]
The glands that secrete zootoxins are a modification of the parotid salivary glands found in other vertebrates and are usually located on each side of the head, below and behind the eye, and enclosed in a muscular sheath. The venom is stored in large glands called alveoli in which it's stored before being conveyed by a duct to the base of kanaled or tubular fangs through which it's ejected.[3][4]
Venom contains more than 20 different compounds, which are mostly proteins and polypeptides.[3][5] The complex mixture of proteins, enzymes, and various other substances has toxic and lethal properties.[2] Venom serves to immobilize prey.[6] Enzymes in venom play an important role in the digestion of prey,[4] and various other substances are responsible for important but non-lethal biological efeks.[2] Some of the proteins in snake venom have very specific efeks on various biological functions, including blood coagulation, blood pressure regulation, and transmission of nerve or muscle stimulasies. These venoms have been studied and developed for use as pharmacological or diagnostic alat, and even drugs.
Proteins constitute 90-95% of venom's dry weight and are responsible for almost all of its biological efeks.[5][7] The hundreds, even thousands, of proteins found in venom include toxins, neurotoxins in particular, as well as nontoxic proteins (which also have pharmacological properties), and many enzymes, especially hydrolytic ones.[2] Enzymes (molecular weight 13-150 KDa) makeup 80-90% of viperid and 25-70% of elapid venoms, including digestive hydrolases, L-amino-acid oxidase, phospholipases, thrombin-like pro-coagulant, and kallikrein-like serine proteases and metalloproteinases (hemorrhagins), which damage vascular endothelium. Polypeptide toxins (molecular weight 5-10 KDa) include cytotoxins, cardiotoxins, and postsynaptic neurotoxins (such as α-bungarotoxin and α-Cobratoxin), which bind to acetylcholine receptors at neuromuscular junctions. Compounds with low molecular weight (up to 1.5 KDa) include metals, peptides, lipids, nucleosides, carbohydrates, amines, and oligopeptides, which inhibit angiotensin-converting enzyme (ACE) and potentiate bradykinin (BPP).
