In enzymology, an amine N-methyltransferase (EC 18.104.22.168) is an enzyme that is ubiquitously present in non-neural tissues and that catalyzes the N-methylation of tryptamine and structurally related compounds.
The chemical reaction taking place is:
Thus, the two substrates of this enzyme are S-adenosyl methionine and amine, whereas its two products are S-adenosylhomocysteine and methylated amine. In the case of tryptamine and serotonin these then become the dimethylated indolethylamines dimethyltryptamine (DMT) and bufotenine.
This enzyme belongs to the family of transferases, specifically those transferring one-carbon group methyltransferases. The systematic name of this enzyme class is S-adenosyl-L-methionine:amine N-methyltransferase. Other names in common use include nicotine N-methyltransferase, tryptamine N-methyltransferase, indolethylamine N-methyltransferase, and arylamine N-methyltransferase. This enzyme participates in tryptophan metabolism.
A wide range of primary, secondary and tertiary amines can act as acceptors, including tryptamine, aniline, nicotine and a variety of drugs and other xenobiotics.
As of late 2007, only one structure has been solved for this class of enzymes, with the PDB accession code 2A14.
- Ansher SS, Jakoby WB (1986). "Amine N-methyltransferases from rabbit liver". J. Biol. Chem. 261 (9): 3996–4001. PMID 3949799.
- Crooks PA, Godin CS, Damani LA, Ansher SS, Jakoby WB (1988). "Formation of quaternary amines by N-methylation of azaheterocycles with homogeneous amine N-methyltransferases". Biochem. Pharmacol. 37 (9): 1673–7. doi:10.1016/0006-2952(88)90426-1. PMID 3377829.