4-dimethylallyltryptophan N-methyltransferase (EC 2.1.1.261, fgaMT (gene), easF (gene)) is an enzyme with systematic name S-adenosyl-L-methionine:4-(3-methylbut-2-enyl)-L-tryptophan N-methyltransferase.^[1] This enzyme catalyses the following chemical reaction

S-adenosyl-L-methionine + 4-dimethylallyl-L-tryptophan ${\displaystyle \rightleftharpoons }$ S-adenosyl-L-homocysteine + 4-dimethylallyl-L-abrine

The enzyme catalyses a step in the pathway leading to biosynthesis of ergot alkaloids in certain fungi.