Table 2.
Enzymes involved in sanguinarine biosynthesis, describing reaction catalyzed and subcellular localization. Data were collected from UniProt Beta (https://beta.uniprot.org/ (accessed on 12 December 2021)).
| Enzyme and EC Number | Function | Subcellular Localization | Organisms amd Acc. Number |
|---|---|---|---|
| l-Tyrosine decarboxylase (TyDC) EC 4.1.1.25 | Decarboxylates of l-tyrosine to produce tyramine | Cytosol |
P. somniferum (P54768) Thalictrum flavum (Q9AXN7) A. mexicana (D2SMM8) |
|
s-Norcoclaurine synthase (NCS) EC 4.2.1.78 |
Condenses dopamine and 4-HPDA, producing s-norcoclaurine | Endoplasmic reticulum lumen and vacuole |
P. somniferum (Q4QTJ2) T. flavum (Q67A25) A. mexicana (EU881891) |
|
s-Norcoclaurine-6-O-methyltransferase (6OMT) EC 2.1.1.128 |
Transfers a methyl group from SAM to s-norcoclaurine, forming coclaurine, and to r,s-norcoclaurine, formimg r-norprotosinomenine, s-norprotosinomenine, and (r,s)-isoorientaline | Membrane integral protein |
P. somniferum (Q6WUC1) Coptis japonica (Q9LEL6) |
| Reticuline oxidase: berberine bridge enzyme (BBE) EC:1.21.3.3 |
Converts s-reticuline in s-scoulerine by forming of a carbon–carbon bond (C8) between the N-methyl group and the phenolic ring | Cytoplasmic vesicles |
P. somniferum (P93479) E. californica (P30986) A. mexicana (D2SMM9) |
| Cheilanthifoline synthase (CheSyn) EC:1.14.19.65 | Converts s-scoulerine into r,s-cheilanthifoline by forming a methylenedioxy brigde | Endoplasmic reticulum membrane |
E. californica (B5UAQ8) A. mexicana (CYP719A14) |
| Stylopine synthase (StySyn) EC:1.14.19.73 |
Forms a methylenedioxy bridge on ring A (2,3 position), transforming s-cheilanthifoline to s-stylopine, s-scoulerine to s-nandinine, and s-tetrahydrocolumbamine to s-canadine | Smooth endoplasmic reticulum membrane |
E. californica (Q50LH4) A. mexicana (B1NF19) |
| s-Tetrahydroprotoberberine N-methyltransferase TNMT EC:2.1.1.122 | Converts stylopine, canadine, and tetrahydropalmatine to their corresponding N-methylated products | Cytosol |
P. somniferum (Q108P1) E. californica C3SBS8 |
| Methyltetrahydroprotoberberine 14-monooxygenase (MSH) EC:1.14.14.97 | Transforms, by oxidation, N-methylstylopine and N-methylcanadine into protopine and allocryptopine, respectively | Membranal protein | P. somniferum (L7X3S1) |
| Protopine 6-hydroxylase (P6H) EC:1.14.14.98 | Converts protopine and allocryptopine to dihydrosanguinarine and dihydrochelerythrine by hydroxylation at position 6 | Endoplasmic reticulum membrane |
E. californica (F2Z9C1) P. somniferum (L7X0L7) |
| Dihydrobenzophenanthridine oxidase (DBOX) EC 1.5.3.12 |
Catalyzes a two-electron oxidation of dihydrosanguinarine, forming sanguinarine | Endoplasmic reticulum | P. somniferum (AAC61839) |
| Sanguinarine reductase (SanR) EC:1.3.1.107 | Catalyzes reduction of benzophenanthridines, preferentially sanguinarine, to the dihydroalkaloids; involved in detoxifying the phytoalexins produced by plant itself | Vacoule | E. californica (D5JWB3) |