This report describes a modular enzyme-catalyzed cascade reaction that transforms l- or d-α-amino acids to β-methyl-α-amino acids. In this process an α-amino acid transaminase, an α-keto acid methyltransferase, and a halide methyltransferase cooperate in two orthogonal reaction cycles that mediate product formation and regeneration of the cofactor pyridoxal-5'-phosphate and the co-substrate S-adenosylmethionine. The only stoichiometric reagents consumed in this process are the unprotected l- or d-α-amino acid and methyl iodide.
Keywords: S-adenosylmethionine; amino acids; biocatalysis; methyltransferase; stereoselective C-alkylation.
© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.