IUBMB Enzyme Nomenclature

EC 4.2.1.78

Accepted name: (S)-norcoclaurine synthase

Reaction: 4-hydroxyphenylacetaldehyde + dopamine = (S)-norcoclaurine + H2O

For diagram click here.

Glossary: dopamine = 4-(2-aminoethyl)benzene-1,2-diol

Other name(s): (S)-norlaudanosoline synthase; 4-hydroxyphenylacetaldehyde hydro-lyase (adding dopamine)

Systematic name: 4-hydroxyphenylacetaldehyde hydro-lyase [adding dopamine; (S)-norcoclaurine-forming]

Comments: 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: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 79122-01-3

References:

1. Stadler, R., Zenk, M.H. A revision of the generally accepted pathway for the biosynthesis of the benzyltetrahydroisoquinoline reticuline. Liebigs Ann. Chem. (1990) 555-562.

2. Stadler, R., Kutchan, T.M., Zenk, M.H. (S)-Norcoclaurine is the central intermediate in benzylisoquinoline alkaloid biosynthesis. Phytochemistry 28 (1989) 1083-1086.

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 (2002) 33878-33883. [PMID: 12107162]

[EC 4.2.1.78 created 1984, modified 1999]


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