N-methyl-L-amino-acid oxidase () is an enzyme that catalyzes the general chemical reaction
Not all amino acids are equally effective as substrates but N-methyltryptophan (L-abrine) is an example which gives a rapid and nearly complete reaction in vitro.
The enzyme is a flavoprotein that uses flavin adenine dinucleotide as its cofactor. It requires oxygen, which is converted to hydrogen peroxide, while the methyl group becomes formaldehyde.
This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-NH group of donors with oxygen as acceptor. The systematic name of this enzyme class is N-methyl-L-amino-acid:oxygen oxidoreductase (demethylating). Other names in common use include N-methylamino acid oxidase, and demethylase.