Proteins constitute 90-95% of<unk> 's weight and are responsible for almost all of its biological effects. The hundreds, even thousands, of proteins found in<unk>  include toxins, neurotoxins in particular, as well as nontoxic proteins (which also have pharmacological properties), and many enzymes, especially hydrolytic ones. Enzymes (molecular weight 13-150 KDa) make up 80-90% of viperid and 25-70% of elapid<unk> s, 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). Inter- and intra-species variation in<unk>  chemical composition is geographical and ontogenic. Phosphodiesterases interfere with the prey's cardiac system, mainly to lower the blood pressure. Phospholipase A2 causes hemolysis by lysing the phospholipid cell membranes of red blood cells. Amino acid oxidases and proteases are used for digestion. Amino acid oxidase also triggers some other enzymes and is responsible for the yellow colour of the<unk>  of some species. Hyaluronidase increases tissue permeability to accelerate the absorption of other enzymes into tissues. Some<unk> s carry fasciculins, like the mambas (Dendroaspis), which inhibit cholinesterase to make the prey lose muscle control. + Main enzymes of<unk>  Type Name Origin Oxidoreductases dehydrogenase lactate Elapidae L-amino-acid oxidase All species Catalase All species Transferases Alanine amino transferase Hydrolases Phospholipase A2 All species Lysophospholipase Elapidae, Viperidae Acetylcholinesterase Elapidae Alkaline phosphatase Bothrops atrox Acid phosphatase Deinagkistrodon acutus 5'-nucleotidase All species Phosphodiesterase All species Deoxyribonuclease All species Ribonuclease 1 All species Adenosine triphosphatase All species Amylase All species Hyaluronidase All species NAD-Nucleotidase All species Kininogenase Viperidae Factor X activator Viperidae, Crotalinae Heparinase Crotalinae α-Fibrinogenase Viperidae, Crotalinae β-Fibrinogenase Viperidae, Crotalinae α-β-Fibrinogenase Bitis gabonica Fibrinolytic enzyme Crotalinae Prothrombin activator Crotalinae Collagenase Viperidae Elastase Viperidae Lyases Glucosaminate ammonia-lyase<unk>  toxins vary greatly in their functions. The two broad classes of toxins found in<unk> s are neurotoxins (mostly found in elapids) and hemotoxins (mostly found in viperids). However, exceptions occur – the<unk>  of the black-necked spitting cobra (Naja nigricollis), an elapid, consists mainly of cytotoxins, while that of the Mojave rattlesnake (Crotalus scutulatus), a viperid, is primarily neurotoxic. Both elapids and viperids may carry numerous other types of toxins. α-neurotoxins α-Bungarotoxin, α-toxin, erabutoxin, cobratoxin β-neurotoxins (PLA2) β-Bungarotoxin, Notexin, ammodytoxin, crotoxin, taipoxin κ-neurotoxins Kappa-bungarotoxin Dendrotoxins (Kunitz) Dendrotoxin, toxins I and K; possibly β-Bungarotoxin chain B Cardiotoxins Naja nigricollis y-toxin, cardiotoxin III (aka cytotoxins) Myotoxins Myotoxin-a, crotamine Sarafotoxins Sarafotoxins a, b, and c Hemorrhagins (metalloprotease) Mucrolysin, Atrolysins, Acutolysins, etc. Hemotoxins (serine protease)<unk> bin A
Snake venom
Ant venom
Alpha-neurotoxin
Neurotoxin
Insect toxin
Dinotoxin
Chlorotoxin
Kurtoxin