amine N-methyltransferase
indolethylamine N-methyltransferase (with slight variation on CPK coloration) – See PDB 2A14​
Identifiers
EC no.	2.1.1.49
CAS no.	51377-47-0
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Gene Ontology	AmiGO / QuickGO
Search PMC articles PubMed articles NCBI proteins

Amine N-methyltransferase (EC 2.1.1.49), also called indolethylamine N-methyltransferase, and thioether S-methyltransferase, is an enzyme that is ubiquitously present in non-neural tissues and catalyzes the N-methylation of tryptamine and structurally related compounds.^[1] More recently, it was discovered that this enzyme can also catalyze the methylation of thioether and selenoether compounds, although the physiological significance of this biotransformation is not yet known.^[2][3]

The chemical reaction taking place is:

• S-adenosyl-L-methionine + an amine ${\displaystyle \rightleftharpoons }$ S-adenosyl-L-homocysteine + a methylated amine

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 N,N-dimethyltryptamine (DMT) and bufotenine respectively.^[4]

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.^[1]

As of late 2007, only one structure has been solved for this class of enzymes, with the PDB accession code 2A14.

• Tryptamine

• Ansher SS, Jakoby WB (1986). "Amine N-methyltransferases from rabbit liver". J. Biol. Chem. 261 (9): 3996–4001. doi:10.1016/S0021-9258(17)35612-0. 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.

• EC 2.1.1.49
• Lyon ES, Jakoby WB (1981). "Arylamine N-methyltransferase". Detoxication and Drug Metabolism: Conjugation and Related Systems. Methods in Enzymology. Vol. 77. pp. 263–6. doi:10.1016/S0076-6879(81)77035-6. ISBN 9780121819774. PMID 6276654.
• Boarder MR, Rodnight R (1976). "Tryptamine-N-methyltransferase activity in brain tissue: a re-examination". Brain Res. 114 (2): 359–64. doi:10.1016/0006-8993(76)90680-6. PMID 963555. S2CID 36334101.