Homo sapiens Reaction:

Superclasses: Reactions Classified By Conversion Type Simple Reactions Chemical Reactions
Reactions Classified By Substrate Small-Molecule Reactions

EC Number:

Enzymes and Genes:
catechol O-methyltransferase : COMT
transmembrane O-methyltransferase : LRTOMT

In Pathway: dopamine degradation

Note that this reaction equation differs from the official Enzyme Commission reaction equation for this EC number, which can be found here .

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

Most BioCyc compounds have been protonated to a reference pH value of 7.3, and some reactions have been computationally balanced for hydrogen by adding free protons. Please see the PGDB Concepts Guide for more information.

Mass balance status: Balanced.

Direct generic reaction:
a catechol + S-adenosyl-L-methionine → a guaiacol + S-adenosyl-L-homocysteine + H+ (

Enzyme Commission Primary Name: catechol O-methyltransferase

Enzyme Commission Synonyms: COMT I , COMT II, S-COMT (soluble form of catechol-O-methyltransferase), MB-COMT (membrane-bound form of catechol-O-methyltransferase), catechol methyltransferase, catecholamine O-methyltransferase

Enzyme Commission Summary:
The mammalian enzyme acts more rapidly on catecholamines such as adrenaline or noradrenaline than on catechols.

Citations: [AXELROD58, Gulliver79, Huh79]

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

Instance reactions of [a catechol + S-adenosyl-L-methionine → a guaiacol + S-adenosyl-L-homocysteine + H+] (
i1: L-dopa + S-adenosyl-L-methionine → 3-O-methyldopa + S-adenosyl-L-homocysteine + H+ (

i2: 3,4-dihydroxyphenylacetate + S-adenosyl-L-methionine → homovanillate + S-adenosyl-L-homocysteine + H+ (
i3: (R)-adrenaline + S-adenosyl-L-methionine → metanephrine + S-adenosyl-L-homocysteine + H+ (

i4: 3,4-dihydroxyphenylglycol + S-adenosyl-L-methionine → 3-methoxy-4-hydroxyphenylglycol + S-adenosyl-L-homocysteine + H+ (

i5: (R)-noradrenaline + S-adenosyl-L-methionine → normetanephrine + S-adenosyl-L-homocysteine + H+ (

i6: S-adenosyl-L-methionine + dopamine → S-adenosyl-L-homocysteine + 3-methoxytyramine + H+ (

i7: 3,4-dihydroxymandelate + S-adenosyl-L-methionine → vanillyl mandelate + S-adenosyl-L-homocysteine + H+ (

Relationship Links: BRENDA:EC: , ENZYME:EC: , IUBMB-ExplorEnz:EC:


AXELROD58: AXELROD J, TOMCHICK R (1958). "Enzymatic O-methylation of epinephrine and other catechols." J Biol Chem 233(3);702-5. PMID: 13575440

Gulliver79: Gulliver PA, Tipton KF (1979). "The purification and properties of pig brain catechol-o-methyltransferase." J Neurochem 32(5);1525-9. PMID: 438821

Huh79: Huh MM, Friedhoff AJ (1979). "Multiple molecular forms of catechol-O-methyltransferase. Evidence for two distinct forms, and their purification and physical characterization." J Biol Chem 254(2);299-308. PMID: 762061

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Please cite the following article in publications resulting from the use of HumanCyc: Genome Biology 6(1):1-17 2004
Page generated by SRI International Pathway Tools version 19.0 on Sat Aug 1, 2015, biocyc13.