Caffeate O-methyltransferase

In enzymology, a caffeate O-methyltransferase (EC 2.1.1.68) is an enzyme that catalyzes the chemical reaction

SAM + caffeic acid ${\displaystyle \rightleftharpoons }$ SAH + ferulic acid

Caffeic acid 3-O-methyltransferase
Alfalfa COMT dimer with bound substrates. PDB: 1KYW​
Identifiers
EC no.	2.1.1.68
CAS no.	50936-45-3
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

Thus, the two substrates of this enzyme are S-adenosyl methionine and 3,4-dihydroxy-trans-cinnamate (caffeic acid), whereas its two products are S-adenosylhomocysteine and 3-methoxy-4-hydroxy-trans-cinnamate (ferulic acid).

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:3,4-dihydroxy-trans-cinnamate 3-O-methyltransferase. Other names in common use include caffeate methyltransferase, caffeate 3-O-methyltransferase, and S-adenosyl-L-methionine:caffeic acid-O-methyltransferase. This enzyme participates in phenylpropanoid biosynthesis.

Structural studies

As of late 2007, two structures have been solved for this class of enzymes, with PDB accession codes 1KYW and 1KYZ.