EC - (S)-norcoclaurine synthase

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IntEnz Enzyme Nomenclature


Accepted name:
(S)-norcoclaurine synthase
Other names:
(S)-norlaudanosoline synthase
4-hydroxyphenylacetaldehyde hydro-lyase (adding dopamine)
Systematic name:
4-hydroxyphenylacetaldehyde hydro-lyase [adding dopamine; (S)-norcoclaurine-forming]



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.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Protein domains and families: PROSITE:PDOC51471
Structural data: CSA , EC2PDB
Gene Ontology: GO:0050474
CAS Registry Number: 79122-01-3


  1. 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).
  2. Stadler, R., Kutchan, T.M., Zenk, M.H.
    (S)-Norcoclaurine is the central intermediate in benzylisoquinoline alkaloid biosynthesis.
    Phytochemistry 28: 1083-1086 (1989).
  3. Samanani, N. and Facchini, P.J.
    Purification and characterization of norcoclaurine synthase. The first committed enzyme in benzylisoquinoline alkaloid biosynthesis in plants.
    J. Biol. Chem. 277: 33878-33883 (2002). [PMID: 12107162]

[EC created 1984, modified 1999]