Scoulerine 9 0 methyltransferase

SATO, F TAKESHITA, N., FITCHEN, J.H., FUJ1WARA, H YAMADA, Y S-Adenosyl-L-methionine scoulerine-9-0-methyltransferase from cultured Coptis japonica cells. Phytochemistry, 1993,32, 659-664. 

Figure 2.6 Biosynthesis of berberine from (5)-reticuline in Berberis species and Coptis japonica. BBE, berberine bridge enzyme SCMT, (5)-scoulerine-9-0-methyltransferase CAS, (5)-canadine synthase STOX, tetrahydroberberine oxidase COX, enzyme found in Coptis japonica.

Takeshita N, Fujiwara H, Mimura H, Fitchen JH, Yamada Y, 48. Sato F. Molecular cloning and characterization of S-adenosyl-L-methionine scoulerine-9-0-methyltransferase from cultured cells... 

Scoulerine 9-0-methyltransferase Coptis Japonica S-adenosylmethionine-dependent 0-methyltransferaae ao—E... 

S. Muemmler, M. Rueffer and M.H. Zenk, S-Adenosylmethionine (S)-Scoulerine-9-0-methyltransferase, a highly stereo- and regiospecific enzyme in tetrahydroberberine bioynthesis. Plant Cell Reports 4 (1985), 36-39. 

Figure 4.2 Biosynthesis of benzylisoquinoline alkaloids. Enzyme abbreviations TYDC, tyrosine/dopa decarboxylase NCS, norcoclaurine synth lse 60MT, norcoclaurine 6-O-methyltransferase 4 OMT, 3 -hydroxy-/V-methylcoclaurine 4 -0-methyltransferase CYP80A, berbamunine synth lse CYP80B, N-methylcoclaurine 3 -hydroxylase BBE, berberine bridge enzyme SOMT, scoulerine 9-0-methyltransferase CYP719A, (S)-canadine synthase SAT, salutaridinol 7-O-acetyltransferase COR, codeinone reductase.

Fig. 17 Sequential enzymatic formation of berberine from (S)-reticuline (BBE berberine bridge enzyme SOMT scoulerine O-methyltransferase THCOX tetrahydrocolumbamine oxidase COX columbamine oxidase)...

Eujiwara, H., Takeshita, N., Terano, Y., Fitchen, J.H., Tsujita, T., Katagiri, Y, Sato, F. and Yamada, Y. (1993) Expression of (S)-scoulerine 9-O-methyltransferase in Coptis japonica plants. Phytochemistry, 34,949-54. 

Administration of triply, 3C-labelled (5)-reticuline to a stable variant non-alkaloid producing cell culture line of Thalictrum tuberosum in cell culture demonstrated a very high incorporation of label into protoberberine alkaloids that were subsequently produced. Since this cell line does not produce reticuline, because the cell line lacks or has insufficient quantities of three methyltransferases that lead to the formation of reticuline, cell cultures that contain this cell line are appropriate for the study of biosynthetic studies., 3C NMR spectroscopy and CIMS were utilized to follow the time course of the metabolism, and demonstrated the rapid formation of scoulerine as a primary reaction product, followed by further tetrahydroprotoberberines and dehydroprotoberberines. The apparently reversible formation of dehydroscoulerine in significant amounts was interpreted as evidence for the role of this compound as an alkaloidal storage product from which scoulerine may be regenerated via enzymic reduction. Scoulerine, dehydroscoulerine, columbamine, and (S)-reticuline were detected by l3C NMR in the crude extracts, while berberine was detected by HPLC. The biosynthetic pathway of these protoberberines in this variant cell culture were summarized as follows [151] (S)-reticuline > scoulerine -> tetrahydrocolumbamine (hypothetical) -> columbamine -> dehydroscoulerine -> candadine -> berberine. 

The hydroxyl moiety at the C-9 position of (S)-scoulerine is methylated by the action of an O-methyltransferase to give (5)-tetrahydroco-lumbamine [8]. Oxygen (1.5 moles) is needed when the tetrahydroberberine-type alkaloid is transformed to columbamine, a pro-toberberine-type alkaloid, and it was clarified that a flavine enzyme which produces 1 mol each of H2O2 and H2O is involved in this reaction. Also, it was shown that the 7,14-dehydroberberinium ion was involved as a biosynthetic intermediate [9]. 

Fig. 8.6 Biosynthetic pathway for benzylisoquinoline alkaloid (BIA) biosynthesis in plants. TYDC tyrosine/dopa decarhoxylase, 60MT norcoclaurine b-O-methyltransfoase, 40OMT 30-hydroxy-Af-methylcoclaurine 40-O-methyltransferase, OMT ITl O-methyltransferase II-l, CYP80A1 berbamunine synthase, CYP80B1 (Si-N-methylcoclaurine 30-hydroxylase, btaber-ine bridge enzyme, SOMT scoulerine iV-methyltransferase, COR codeinone rednctase (Adopted from Ref. [3])...

Reticuline is a chemical compound that can be found in Lindera aggregata. It is also one of the alkaloids found in opium. Metabolism showed that 3 -hydroxy-A -methyl-(S)-coclaurine 4 -0-methyltransferase uses 5-adenosyl methionine and 3 -hydroxy-A -methyl-(S)-coclaurine to produce S-adenosylhomocysteine and (S)-reticuline. Reticuline oxidase uses (S)-reticuline and O2 to produce (S)-scoulerine and H2O2. Salutaridine synthase uses (R)-reticuline, NADPH, H", and O2 to produce salutaridine, NADP", and H2O. 1,2-dehydroreticulinium reductase (NADPH) uses (R)-reticuline and NADP + to produce 1,2-dehydroreticulinium, NADPH, and H". ... 

Fig. 4 Pathways of benzylisoquinoline biosynthesis. A selection of biosynthetic enzymes is notified with their localization in the cytosol (yellow), the ER membrane (red) or in the lumen of cytosolic vesicles (blue). Informations are taken mainly from Facchini and St-Pierre (2005), Bock et al. (2002), own experiments and other references cited in the text. BBE, berberine bridge enzyme CFS, cheilanthifoline synthase CNMT, coclaurine N-methyltransferase COR, codeinone reductase DBOX, dihydrobenzophen-anthridine oxidase MSH, N-methylstylopine 14-hydroxylase NCS, norcoclaurine synthase NMCH, N-methylcoclaurme 3 -hydroxylase 4 OMT, 3 -hydroxy-N-methylcoclaurine 4 -0-methyltransferase 60MT, norcoclaurine 6-O-methyltransferase 70MT, reticuline 7-O-methyltransferase P6H, protopine 6-hydroxylase SAT, salutaridinol-7-O-acetyltransferase SOR, salutaridineiNADPH 7-oxidoreductase STS, stylopine synthase SAS, salutaridine synthase TNMT, tetrahydroprotoberberine cis-N-methyltrans-ferase TYDC, tyrosine decarboxylase CAS, canadine sjmthase SOMT, scoulerine 9-O-methyltransferase STOX, (S)-tetrahydroprotoberberine oxidase...

In summary, the substrate specificity shows the enzyme to act preferentially on (S)-scoulerine and not on the oxidized scoulerine product containing an aromatic C-ring. The methyltransferase is highly specific for the 9-hydroxy position of (S)-scou-lerine. One can therefore conclude that methylation of the tetrahydroberberine molecule occurs prior to the oxidation of ring C. 

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