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discounted EARLY registration ends Dec 31, 2014
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discounted EARLY registration ends Dec 31, 2014
Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
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MetaCyc Enzyme: coclaurine N-methyltransferase

Gene: AB061863 Accession Number: G-6405 (MetaCyc)

Species: Coptis japonica

Subunit composition of coclaurine N-methyltransferase = [AB061863]4
         coclaurine N-methyltransferase = AB061863

Gene Citations: [Choi02a]

Molecular Weight of Polypeptide: 41.7 kD (from nucleotide sequence), 45 kD (experimental) [Choi01 ]

Molecular Weight of Multimer: 160 kD (experimental) [Choi01]

pI: 4.2 [Choi01]

Relationship Links: Entrez-Nucleotide:PART-OF:AB061863

Gene-Reaction Schematic: ?


Enzymatic reaction of: S-adenosyl-L-methionine:(S)-corytuberine-N-methyltransferase (coclaurine N-methyltransferase)

EC Number: 2.1.1.-

(S)-corytuberine + S-adenosyl-L-methionine <=> magnoflorine + S-adenosyl-L-homocysteine + H+

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

The reaction is physiologically favored in the direction shown.

In Pathways: magnoflorine biosynthesis

Summary:
Using a crude enzyme preparation of the C. japonica recombinant coclaurine N-methyltransferase, it was shown that coclaurine N-methyltransferase can also convert (S)-corytuberine to magnoflorine. No details about its catalytic properties with the substrate (S)-corytuberine is available.

Citations: [Ikezawa08]


Enzymatic reaction of: S-adenosyl-L-methionine: coclaurine N-methyltransferase

EC Number: 2.1.1.140

(S)-coclaurine + S-adenosyl-L-methionine <=> (S)-N-methylcoclaurine + S-adenosyl-L-homocysteine + H+

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

The reaction is physiologically favored in the direction shown.

Alternative Substrates for (S)-coclaurine: (R,S)-norlaudanosoline [Choi01 ] , (R,S)-norreticuline [Choi01 ] , (R)-coclaurine [Choi01 ]

In Pathways: (S)-reticuline biosynthesis I

Summary:
Coclaurine N-methyltransferase (CNMT) has broad substrate specificity with isoquinoline substrates and is not stereo-specific. However, the lack of methylation activity towards 4-O-methyldopamine, tryptamine, histamine and purine indicates that the isoquinoline ring is important for the methyltransfer reaction. The enzyme activity does not require any metal ion. Whereas some O-methyltransferases are inhibited by SH-directed inhibitors such as p-chloromercuribenzoate and iodoacetamide, neither chemicals at 5 mM inhibited the purified Coptis japonica CNMT.

Inhibitors (Unknown Mechanism): Co2+ [Choi01] , Cu2+ [Choi01] , Mn2+ [Choi01]

pH(opt): 7.0 [Choi01]


References

Choi01: Choi KB, Morishige T, Sato F (2001). "Purification and characterization of coclaurine N-methyltransferase from cultured Coptis japonica cells." Phytochemistry 56(7);649-55. PMID: 11314949

Choi02a: Choi KB, Morishige T, Shitan N, Yazaki K, Sato F (2002). "Molecular cloning and characterization of coclaurine N-methyltransferase from cultured cells of Coptis japonica." J Biol Chem 277(1);830-5. PMID: 11682473

Ikezawa08: Ikezawa N, Iwasa K, Sato F (2008). "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(14);8810-21. PMID: 18230623


Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by SRI International Pathway Tools version 18.5 on Fri Nov 28, 2014, BIOCYC13B.