Polypeptides from snake venom

Harris, J.B. Polypeptides from snake venoms which act on nerve and muscle. In Progress in Medicinal Chemistry, edited by Ellis, G.P. and West, G.B. Amsterdam Elsevier, 1984, p. 63-110. 

Presynaptic toxins - polypeptide snake venoms This group contains multimeric polypeptides containing subunits with phospholipase Aj activity, and often contains other subunits with a chaperone role. Toxicity does not normally rest on enzyme activity alone, and binding may occur other than on neuronal tissue, e.g. some cause skeletal muscle cytotoxicity. Examples from snake and viper venoms include agkistrodotoxin, ammodytoxin A. P-bungarotoxins. mojave toxin, notexin. taipoxin and textilotoxin. 

Biologically active polymers are of fundamental importance in the life process Itself. He need only note that molecules such as the proteins, nucleic acids, enzymes and many complex sugars are macromolecular in nature to realize how dependent life is upon polymer molecules. In addition, many of the polypeptide hormones are derived from a larger polypeptide or are synthesized by means of other macromolecules. Nearly all our foods and most of our bodies are composed of polymers and most of these are bloactive. He can note with certainty that macromolecules are essential to life as we know it. Beyond this, the interaction of macromolecules plays an Important role in many areas of life. Examples of this could Include such divergent effects as the pain-killing activity of the enkephalins or the toxic nature of snake venom which is a polypeptide in most cases. In subsequent chapters of this book, other authors will consider a variety of polymeric systems with various types of actual or potential activity with humans, animals and/or plants. In this chapter, we briefly explore the overall realm of biologically active polymers. 

The third type of presynaptic toxin is a tertiary complex of three polypeptide chains. Taipoxin from the venom of the Australian snake, taipan, has three subunits, a, p, and y, with an Mr of46,000. The number of amino acid residues present in the subunits is 120, 120, and 135, respectively. The a-chain is basic and has phospholipase A activity. 

Dajas, F., Bolioli, B., Gastello, M. E., and Silveira, R. (1987). Rat striatal acetylcholinesterase inhibition by fasciculin (a polypeptide from green mamba snake venom). Neurosci. Lett. 77 87-91. 

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