%0 Journal Article %A Salinger, Matthew T %A Castellano Garrido, Daniel %A Lamming, Eleanor D %A Ward, John M %A Moody, Thomas S %A Jeffries, Jack WE %A Hailes, Helen C %D 2024 %F discovery:10193493 %I Wiley %J ChemCatChem %K biocatalysis, methyltransferases, methylation, cascade, catechols %N 7 %T An Alternative Cascade for the Selective Methylation of Catechols and Tetrahydroisoquinolines by O-Methyltransferases %U https://discovery.ucl.ac.uk/id/eprint/10193493/ %V 16 %X Methyltransferases are gaining traction as a method to achieve greener and regioselective methylations of a wide array of substrates. In this work, a halide methyltransferase biomethylation cascade was successfully adapted with the incorporation of a methionine adenosyltransferase to generate the S‐adenosyl‐L‐methionine (SAM) methylation cofactor in situ from less costly ATP and L‐methionine, instead of directly adding SAM to start the cascade. Furthermore, this cascade was applied to achieve novel catechol and tetrahydroisoquinoline methylations with the O‐methyltransferases RnCOMT, MxSafC and NpN4OMT with high conversions and regioselectivities. In addition, the cascade was successfully trialled with the less toxic methyl group donor, methyl tosylate. %Z © 2024 The Authors. ChemCatChem published by Wiley-VCH GmbH. This is an open access article under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/).