Trimethylamine dehydrogenase () is an enzyme that catalyzes the chemical reaction
The three substrates of this enzyme are trimethylamine, water, and an electron-transferring flavoprotein. Its products are dimethylamine, formaldehyde, and the reduced flavoprotein.
This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-NH group of donors with a flavin as acceptor. The systematic name of this enzyme class is trimethylamine:electron-transferring flavoprotein oxidoreductase (demethylating). It uses one cofactor, flavin mononucleotide. A similar enzyme, dimethylamine dehydrogenase, converts dimethylamine to methylamine.