KEGG   ENZYME: 4.2.1.78Help
Entry
EC 4.2.1.78                 Enzyme                                 

Name
(S)-norcoclaurine synthase;
(S)-norlaudanosoline synthase;
4-hydroxyphenylacetaldehyde hydro-lyase (adding dopamine)
Class
Lyases;
Carbon-oxygen lyases;
Hydro-lyases
BRITE hierarchy
Sysname
4-hydroxyphenylacetaldehyde hydro-lyase [adding dopamine; (S)-norcoclaurine-forming]
Reaction(IUBMB)
4-hydroxyphenylacetaldehyde + dopamine = (S)-norcoclaurine + H2O [RN:R04305]
Reaction(KEGG)
R04305;
(other) R04084
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Substrate
4-hydroxyphenylacetaldehyde [CPD:C03765];
dopamine [CPD:C03758]
Product
(S)-norcoclaurine [CPD:C06160];
H2O [CPD:C00001]
Comment
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.
History
EC 4.2.1.78 created 1984, modified 1999
Pathway
Isoquinoline alkaloid biosynthesis
Metabolic pathways
Biosynthesis of secondary metabolites
Orthology
K13382  
(S)-norcoclaurine synthase
Reference
1
  Authors
Stadler, R., Zenk, M.H.
  Title
A revision of the generally accepted pathway for the biosynthesis of the benzyltetrahydroisoquinoline reticuline.
  Journal
Liebigs Ann. Chem. (1990) 555-562.
Reference
2
  Authors
Stadler, R., Kutchan, T.M., Zenk, M.H.
  Title
(S)-Norcoclaurine is the central intermediate in benzylisoquinoline alkaloid biosynthesis.
  Journal
Phytochemistry 28 (1989) 1083-1086.
Reference
3  [PMID:12107162]
  Authors
Samanani N, Facchini PJ.
  Title
Purification and characterization of norcoclaurine synthase. The first committed enzyme in benzylisoquinoline alkaloid biosynthesis in plants.
  Journal
J. Biol. Chem. 277 (2002) 33878-83.
Other DBs
ExplorEnz - The Enzyme Database: 
IUBMB Enzyme Nomenclature: 
ExPASy - ENZYME nomenclature database: 
BRENDA, the Enzyme Database: 
CAS: 
79122-01-3

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