Orellanine (Webcaps and you)

I don't think I'll ever be able to pick out which mushrooms aren't poisonous. Poisons vary pretty widely across species; a lot of them are small peptide type molecules. One of the few simple small molecule mushroom poisons is orellanine:

i-d0f1b9d7286abb744e53add024f42432-orellanine.gif

It bears a striking similarity to the bipyridyl ligand previously covered, Methyl Viologen (Paraquat).

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Very interesting that orellanine trashes the kidneys whereas the peptide toxins in Amanita and others are primarily hepatotoxic. My guess would be that the N-oxide prevents orellanine from being taken up by the organic anion transport protein (OATP) in the liver and is instead concentrated in the kidney by glomerular filtration.

How do the small peptide toxins found in fungi manage to evade the peptide shredders and mincers in the stomach? I can understand spider and snake peptides doing the business as they are direct injected, but I thought anything made of amino acids entering the stomach was dismantled before doing any harm (or good).

By agogmagog (not verified) on 16 Jan 2007 #permalink

Orellanine is the perfect CSI-resistant poison. Though its ED(50) is somewhat immodest, it requires up to two weeks to do its dirty work. What is the first treatment of kidney failure? Dialysis! No evidence remains to be found.

Does it make a pretty textile lake with iron, chromium, or aluminum mordants? Aqueous extract of Syrian rue gives eye-piercing Turkish Red as the alum lake on wool. Islam may have come about when a sweaty Arab absorbed said harmine alkaloids while sitting on his bright red carpet.