KEGG   ENZYME: 4.2.1.78
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
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
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
ec00950  Isoquinoline alkaloid biosynthesis
ec01100  Metabolic pathways
ec01110  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 555-562 (1990)
Reference
2
  Authors
Stadler, R., Kutchan, T.M., Zenk, M.H.
  Title
(S)-Norcoclaurine is the central intermediate in benzylisoquinoline alkaloid biosynthesis.
  Journal
Phytochemistry 28:1083-1086 (1989)
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 277:33878-83 (2002)
DOI:10.1074/jbc.M203051200
Other DBs
ExplorEnz - The Enzyme Database: 4.2.1.78
IUBMB Enzyme Nomenclature: 4.2.1.78
ExPASy - ENZYME nomenclature database: 4.2.1.78
BRENDA, the Enzyme Database: 4.2.1.78
CAS: 79122-01-3
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