The Australian platypus, is a marsupial with a unique feature - in that the males of the species have venom sacs around their hind-claws.

My understanding is that this venom is not lethal to humans, however, how potent is this venom to other animals?

Also, how does the platypus 'manufacture' this venom?


The Internet says that platypus venom can kill small animals, but I haven't come up with a definitive source for this.

There is an informative Wikipedia page about the venom here. Basically the venom contains a number of toxic peptides including a family of C-type natriuretic peptides, some defensin-like peptides and nerve growth factor. Defensins are very widely-distributed in nature but typically are used by cells as antimicrobials. Natriuretic peptides have a range of effects upon fluid balance and blood pressure control - these are the best-characterized components of platypus venom.

These peptides are all genetically-encoded, so they are made as segments of precursor polypeptides. Intriguingly some of the the C-type natriuretic peptides contain a D-Leu residue. (All of the amino acids used in protein synthesis are the L stereoisomeric forms.) The presence of a D-amino acid in a peptide derived from a genetically-encoded molecule suggest that there must be a specific isomerase present, and evidence for this isomerase in the venom has indeed been found as reported in Torres et al. (2006) Mammalian L-to-D-amino-acid-residue isomerase from platypus venom. FEBS Lett.580:1587–1591. The introduction to this article states:

Platypus venom contains many non-protein and protein components...whose roles are yet to be established.


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