- Sanguinarine is reduced by NADH through a covalent adduct
-
Sanguinarine is a benzo[c]phenanthridine alkaloid with interesting cytotoxic properties, such as induction of oxidative DNA damage and very rapid apoptosis, which is not mediated by p53-dependent signaling. It has been previously documented that sanguinarine is reduced with NADH even in absence of any enzymes while being converted to its dihydro form. We found that the dark blue fluorescent species, observed during sanguinarine reduction with NADH and misinterpreted by Matkar et al. (Arch. Biochem. Biophys. 2008, 477, 43–52) as an anionic form of the alkaloid, is a covalent adduct formed by the interaction of NADH and sanguinarine. The covalent adduct is then converted slowly to the products, dihydrosanguinarine and NAD+, in the second step of reduction. The product of the reduction, dihydrosanguinarine, was continually re-oxidized by the atmospheric oxygen back to sanguinarine, resulting in further reacting with NADH and eventually depleting all NADH molecules. The ability of sanguinarine to diminish the pool of NADH and NADPH is further considered when explaining the sanguinarine-induced apoptosis in living cells.
- Sandor, Roman,Slanina, Jiri,Midlik, Adam,Sebrlova, Kristyna,Novotna, Lucie,Carnecka, Martina,Slaninova, Iva,Taborsky, Petr,Taborska, Eva,Pes, Ondrej
-
-
Read Online
- A novel C-C radical-radical coupling reaction promoted by visible light: Facile synthesis of 6-substituted: N -methyl 5,6-dihydrobenzophenanthridine alkaloids
-
A novel photoredox-mediated direct intermolecular C-H functionalization of N-methyl 5,6-dihydrobenzophenanthridine is developed utilizing the visible light-induced reductive quenching pathway of photocatalyst Ir(ppy)3. In the proposed coupling mechanism, an α-amino C-radical is generated at the 6-position of N-methyl 5,6-dihydrobenzophenanthridine which is capable of coupling with α-EWG (electron withdrawing group) substituted C-radicals. The utility of this methodology has been demonstrated via rapid access to the analogue of natural 6-substituted N-methyl 5,6-dihydrobenzophenanthridine alkaloids.
- Liu, Zhaoying,Huang, Yajun,Xie, Hongqi,Liu, Wei,Zeng, Jianguo,Cheng, Pi
-
p. 50500 - 50505
(2016/06/09)
-
- Isolation and characterization of a cDNA encoding (S)-cis-N-methylstylopine 14-hydroxylase from opium poppy, a key enzyme in sanguinarine biosynthesis
-
Sanguinarine is a benzo[. c]phenenthridine alkaloid with potent antimicrobial properties found commonly in plants of the Papaveraceae, including the roots of opium poppy (. Papaver somniferum). Sanguinarine is formed from the central 1-benzylisoquinoline intermediate (. S)-reticuline via the protoberberine alkaloid (. S)-scoulerine, which undergoes five enzymatic oxidations and an N-methylation. The first four oxidations from (. S)-scoulerine are catalyzed by cytochromes P450, whereas the final conversion involves a flavoprotein oxidase. All but one gene in the biosynthetic pathway from (. S)-reticuline to sanguinarine has been identified. In this communication, we report the isolation and characterization of (. S)-. cis-. N-methylstylopine 14-hydroxylase (MSH) from opium poppy based on the transcriptional induction in elicitor-treated cell suspension cultures and root-specific expression of the corresponding gene. Along with protopine 6-hydroxylase, which catalyzes the subsequent and penultimate step in sanguinarine biosynthesis, MSH is a member of the CYP82N subfamily of cytochromes P450. The full-length MSH cDNA was expressed in Saccharomyces cerevisiae and the recombinant microsomal protein was tested for enzymatic activity using 25 benzylisoquinoline alkaloids representing a wide range of structural subgroups. The only enzymatic substrates were the N-methylated protoberberine alkaloids N-methylstylopine and N-methylcanadine, which were converted to protopine and allocryptopine, respectively.
- Beaudoin, Guillaume A.W.,Facchini, Peter J.
-
p. 597 - 603
(2013/05/08)
-
- Characterization of a flavoprotein oxidase from opium poppy catalyzing the final steps in sanguinarine and papaverine biosynthesis
-
Benzylisoquinoline alkaloids are a diverse class of plant specialized metabolites that includes the analgesic morphine, the antimicrobials sanguinarine and berberine, and the vasodilator papaverine. The two-electron oxidation of dihydrosanguinarine catalyzed by dihydrobenzophenanthridine oxidase (DBOX) is the final step in sanguinarine biosynthesis. The formation of the fully conjugated ring system in sanguinarine is similar to the four-electron oxidations of (S)-canadine to berberine and (S)-tetrahydropapaverine to papaverine. We report the isolation and functional characterization of an opium poppy (Papaver somniferum) cDNA encoding DBOX, a flavoprotein oxidase with homology to ( S)-tetrahydroprotoberberine oxidase and the berberine bridge enzyme. A query of translated opium poppy stem transcriptome databases using berberine bridge enzyme yielded several candidate genes, including an (S)-tetrahydroprotoberberine oxidase-like sequence selected for heterologous expression in Pichia pastoris. The recombinant enzyme preferentially catalyzed the oxidation of dihydrosanguinarine to sanguinarine but also converted (RS)-tetrahydropapaverine to papaverine and several protoberberine alkaloids to oxidized forms, including (RS)-canadine to berberine. The Km values of 201 and 146 μM for dihydrosanguinarine and the protoberberine alkaloid (S)-scoulerine, respectively, suggested high concentrations of these substrates in the plant. Virus-induced gene silencing to reduce DBOX transcript levels resulted in a corresponding reduction in sanguinarine, dihydrosanguinarine, and papaverine accumulation in opium poppy roots in support of DBOX as a multifunctional oxidative enzyme in BIA metabolism.
- Hagel, Jillian M.,Beaudoin, Guillaume A. W.,Fossati, Elena,Ekins, Andrew,Martin, Vincent J. J.,Facchini, Peter J.
-
p. 42972 - 42983
(2013/03/13)
-
- THE PYROLYSIS AND PHOTOLYSIS OF THE PROTOPINE TYPE ALKALOID N-OXIDES. THE SYNTHESIS OF THE SECOBERBINES AND BENZOPHENANTHRIDINES
-
The pyrolysis of the N-oxides of the protopine-type alkaloids afforded three products, one of which was converted to the naturally occurring secoberbines.The photolysis of the N-oxides of the protopines supplied the benzophenanthridines as well as the one of the pyrolysis products.
- Iwasa, Kinuko,Takao, Narao
-
p. 1535 - 1539
(2007/10/02)
-