PSY 005 Lecture Notes - Lecture 10: Peripheral Nervous System, Calreticulin, Glycosidic Bond
12 Sep 2020
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Document Summary
Many plants have evolved chemical defences to either prevent or minimise predation by microorganisms, insects or herbivorous animals. One group of plant toxins that has been extensively studied over the last twenty years or so is the ribosome-inactivating proteins (rips). Ricin is a potent type 2 rip found in the seeds of the castor oil plant ricinus communis. It consists of two glycoprotein chains a and b linked together by a disulphide bond. The chains each have a molecular mass of about 30kda. Like botulinus toxin, the a chain is enzymatically active and acts as the warhead" whereas the b chain is involved in the binding of the toxin to target cells. Mechanism of action: binding to the surface of target cells sufficiently well characterised in the last few years for it to be clear that there are six basic steps: The mechanism(s) of ricin"s cytotoxic effect is not fully understood but has been.
