Regiocomplementary O-Methylation of Catechols by Using Three-Enzyme Cascades

Area of Science:

• Biocatalysis
• Enzymatic Chemistry
• Organic Synthesis

Background:

• S-Adenosylmethionine (SAM)-dependent enzymes offer potential for selective alkylation.
• Enzymatic methylation is often limited by SAM supply and byproduct inhibition.
• Catechol O-methylation presents regioselectivity challenges.

Purpose of the Study:

• To investigate the regioselective O-methylation of catechols using an enzyme cascade.
• To overcome limitations of stoichiometric SAM supply and byproduct inhibition in enzymatic methylation.
• To establish a catalytic system for SAM-dependent alkylation processes.

Main Methods:

• Enzyme cascade setup involving SAM regeneration from L-methionine and ATP using methionine adenosyltransferase.
• Utilized SafC from saframycin biosynthesis for 4-O-methylation of dopamine and dihydrocaffeic acid.
• Employed rat catechol O-methyltransferase for regioselective 3-O-methylation.
• Demonstrated the positive impact of a nucleosidase on overall conversion.

Main Results:

• Achieved 40-70% yield and high selectivity in the 4-O-methylation step using SafC.
• Successfully demonstrated regioselective 3-O-methylation using catechol O-methyltransferase.
• Confirmed the beneficial effect of a nucleosidase in the enzyme cascade.
• Established key milestones towards catalytic SAM-dependent alkylation.

Conclusions:

• The developed enzyme cascade effectively addresses SAM supply and byproduct inhibition issues.
• This approach enables regioselective O-methylation of catechols with high selectivity.
• The findings represent significant progress in developing catalytic SAM-dependent alkylation processes.