Fumitremorgins are tremorogenic metabolites of Aspergillus and Penicillium[1] that belong to a class of naturally occurring 2,5-diketopiperazines.

Three different cytochrome P450 monooxygenases involved in the biosynthesis of furmitremorgin C are FtmC, FtmE, and FtmG.

The enzyme that catalyzes this methylation reaction has not been fully identified, but FtmD is suspected to be the plausible candidate.

Then, the cyclization of tryprostatin A produces fumitremorgin C by forming the C-N bond by FtmE.

Fumitremorgin B is formed by another prenyltransferase, FtmH, that prenylates at N-1 of the indole ring.