molecule of the day: anisomycin

The molecule of the day is anisomycin:

(PubChem)
It's a natural product from Streptomyces that inhibits protein translation in eukaryotes.  It can be used to determine whether a phenomenon depends on protein synthesis.

molecule of the day: leupeptin

The molecule of the day is leupeptin:

(PubChem)
It's a protease inhibitor produced by actinomycetes (source), which, as far as I can tell, is a polyphyletic group.