Neurotoxins affect the nervous system. They may paralyze the breathing apparatus, leading to death. While most rattlesnake venom exhibits minimal neurotoxic activity in comparison to such snakes as the cobra, the venom of Crotalus durissus terrificus, a South American rattlesnake, has a powerful neurotoxin called crotoxin. Crotoxin is a mixture of different substances, including crotoxin B, its biologically active neurotoxic enzyme, and crotoxin A. This latter component causes no harm by itself, but its presence is necessary for the neurotoxic activity of crotoxin B. The venom of the Mohave rattlesnake also has a neurotoxic component called Mohave toxin; but this toxin does not occur in every individual Mohave rattlesnake.
The venom of Crotalus durissus terrificus contains glyroxin, a serine protease. Serine is a component part of many proteins. A protease is an enzyme that breaks down proteins. Therefore, a serine protease is an enzyme that breaks down proteins that contain serine. Rattlesnake venom contains many other proteases besides glyroxin. As a result, when rattlesnake venom gets into the blood stream, these proteases damage the proteins with which they come in contact.
The venom of the eastern diamondback rattlesnake contains adamalysin II, an enzyme that breaks down serine protease inhibitors (SERPINs). Consequently, the disabled SERPINs will not be able to protect proteins from the proteolytic action of proteases that are present in the rattlesnake's venom. The distinguishing feature of adamalysin II is a zinc ion that plays a crucial role in its enzymatic activity.
Phospholipase A2 is a component in the venom of several species of rattlesnakes, such as the western diamondback rattlesnake. Phospholipids are essential components of animal cell membranes. Phospholipase degrades phospholipids, so that when this enzyme comes in contact with the inner surface of blood vessels, the blood vessels will suffer damage. For this reason, rattlesnake bites often cause serious hemorrhaging.
The venom of many rattlesnakes contains L-amino acid oxidase. As the name implies, it damages amino acids by oxidizing them. It helps bring about hemorrhages and cell death in the victims of rattlesnake bites, but its role is imperfectly understood, according to "Snake Venom L-amino Acid Oxidases" by X.Y. Wu and K.J. Clemetson.
Components of rattlesnake venom cause platelets to aggregate so that not enough platelets are available for clotting. In timber rattlesnake venom, a component called crotalocytin has this effect.
Many other components occur in the venom of rattlesnakes. The enzymes ribonuclease and deoxyribonuclease attack nucleic acids. Transaminase causes havoc by removing an amino group (NH2) from one compound and transferring it to another, rendering both dysfunctional. Inert elements also occur, such as albumin.