EC 1.14.19.51     
Accepted name: (S)-corytuberine synthase
Reaction: (S)-reticuline + [reduced NADPH—hemoprotein reductase] + O2 = (S)-corytuberine + [oxidized NADPH—hemoprotein reductase] + 2 H2O.
Other name(s): CYP80G2
Systematic name: (S)-reticuline,NADPH:oxygen oxidoreductase (C-C phenol-coupling; (S)-corytuberine-forming)
Comments: A cytochrome P-450 (heme-thiolate) protein. The enzyme is involved in the biosynthesis of the quaternary benzylisoquinoline alkaloid magnoflorine in the plant Coptis japonica. It is specific for (S)-reticuline.
References:
1.  Ikezawa, N., Iwasa, K. and Sato, F. Molecular cloning and characterization of CYP80G2, a cytochrome P450 that catalyzes an intramolecular C-C phenol coupling of (S)-reticuline in magnoflorine biosynthesis, from cultured Coptis japonica cells. J. Biol. Chem. 283 (2008) 8810–8821. [PMID: 18230623]
[EC 1.14.19.51 created 2017]
 
 
EC 2.1.1.337     
Accepted name: reticuline N-methyltransferase
Reaction: (1) S-adenosyl-L-methionine + (S)-reticuline = S-adenosyl-L-homocysteine + (S)-tembetarine
(2) S-adenosyl-L-methionine + (S)-corytuberine = S-adenosyl-L-homocysteine + (S)-magnoflorine
Glossary: (S)-reticuline = (1S)-1-(3-hydroxy-4-methoxybenzyl)-6-methoxy-2-methyl-1,2,3,4-tetrahydroisoquinolin-7-ol
(S)-tembetarine = (1S)-1-(3-hydroxy-4-methoxybenzyl)-6-methoxy-2,2-dimethyl-1,2,3,4-tetrahydroisoquinolin-7-ol
(S)-corytuberine = (6aS)-2,10-dimethoxy-6-methyl-5,6,6a,7-tetrahydro-4H-dibenzo[de,g]quinoline-1,11-diol
(S)-magnoflorine = (6aS)-1,11-dihydroxy-2,10-dimethoxy-6,6-dimethyl-5,6,6a,7-tetrahydro-4H-dibenzo[de,g]quinolinium
Other name(s): RNMT
Systematic name: S-adenosyl-L-methionine:(S)-reticuline N-methyltransferase
Comments: The enzyme from opium poppy (Papaver somniferum) can also methylate (R)-reticuline, tetrahydropapaverine, (S)-glaucine and (S)-bulbocapnine. It is involved in the biosynthesis of the quaternary benzylisoquinoline alkaloid magnoflorine.
References:
1.  Morris, J.S. and Facchini, P.J. Isolation and characterization of reticuline N-methyltransferase involved in biosynthesis of the aporphine alkaloid magnoflorine in opium poppy. J. Biol. Chem. 291 (2016) 23416–23427. [PMID: 27634038]
[EC 2.1.1.337 created 2017]
 
 


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