EC	3.5.99.14
Accepted name:	(S)-norcoclaurine synthase
Reaction:	(S)-norcoclaurine + H2O = dopamine + 4-hydroxyphenylacetaldehyde
Glossary:	dopamine = 4-(2-aminoethyl)benzene-1,2-diol
Other name(s):	(S)-norlaudanosoline synthase; 4-hydroxyphenylacetaldehyde hydro-lyase (adding dopamine); 4-hydroxyphenylacetaldehyde hydro-lyase [adding dopamine, (S)-norcoclaurine-forming]
Systematic name:	(S)-norcoclaurine dopamine hydrolase (4-hydroxyphenylacetaldehyde-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.
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 3.5.99.14 created 1984 as EC 4.2.1.78, modified 1999, transferred 2024 to EC 3.5.99.14]