Virtually every chemical reaction in the cell occurs in the presence of a catalyst. Most catalysts are proteins. It's important to understand the structure of these proteins in order to get some handle on what they do and how they do it. The proteins in snake venom carry out functions in the human body, just like our own proteins. For example, many types of venom contain enzymes that trigger chemical reactions.
Natural enzymes work to help the body, but the enzymes in snake venom have harmful effects.
Bieber studies the venom of the Mojave Rattlesnake, which is found extensively throughout Arizona. The Mojave's venom contains a poison called a neurotoxin. Neurotoxins affect nerve cells, or neurons, and can cause paralysis and eventually, death. Neurotoxins work by preventing neurons from communicating with each other. Normally, neurons communicate using chemical messengers called neurotransmitters.