EC 220.127.116.11 Enzyme
4-hydroxyphenylacetaldehyde hydro-lyase (adding dopamine)
4-hydroxyphenylacetaldehyde hydro-lyase [adding dopamine; (S)-norcoclaurine-forming]
4-hydroxyphenylacetaldehyde + dopamine = (S)-norcoclaurine + H2O [RN:
The reaction makes a six-membered ring by forming a bond between C-6 of the 3,4-dihydroxyphenyl group of the dopamine and C-1 of the aldehyde in the imine formed between the substrates. The product is the precursor of the benzylisoquinoline alkaloids in plants. The enzyme, formerly known as (S)-norlaudanosoline synthase, will also catalyse the reaction of 4-(2-aminoethyl)benzene-1,2-diol + (3,4-dihydroxyphenyl)acetaldehyde to form (S)-norlaudanosoline, but this alkaloid has not been found to occur in plants.
EC 18.104.22.168 created 1984, modified 1999
Isoquinoline alkaloid biosynthesis
Biosynthesis of secondary metabolites
Stadler, R., Zenk, M.H.
A revision of the generally accepted pathway for the biosynthesis of the benzyltetrahydroisoquinoline reticuline.
Liebigs Ann Chem 555-562 (1990)
Stadler, R., Kutchan, T.M., Zenk, M.H.
(S)-Norcoclaurine is the central intermediate in benzylisoquinoline alkaloid biosynthesis.
Phytochemistry 28:1083-1086 (1989)
Samanani N, Facchini PJ.
Purification and characterization of norcoclaurine synthase. The first committed enzyme in benzylisoquinoline alkaloid biosynthesis in plants.
J Biol Chem 277:33878-83 (2002)
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